WO2024095592A1 - Electric power transfer device and method for controlling same, electric power receiver, and storage medium - Google Patents

Electric power transfer device and method for controlling same, electric power receiver, and storage medium Download PDF

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Publication number
WO2024095592A1
WO2024095592A1 PCT/JP2023/031862 JP2023031862W WO2024095592A1 WO 2024095592 A1 WO2024095592 A1 WO 2024095592A1 JP 2023031862 W JP2023031862 W JP 2023031862W WO 2024095592 A1 WO2024095592 A1 WO 2024095592A1
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Prior art keywords
power
power transmitting
transmission
value
power transmission
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PCT/JP2023/031862
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French (fr)
Japanese (ja)
Inventor
龍太 水森
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キヤノン株式会社
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Publication of WO2024095592A1 publication Critical patent/WO2024095592A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/60—Circuit arrangements or systems for wireless supply or distribution of electric power responsive to the presence of foreign objects, e.g. detection of living beings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/80—Circuit arrangements or systems for wireless supply or distribution of electric power involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Definitions

  • This disclosure relates to a power transmission device for wireless power transmission, a control method thereof, a power receiving device, a storage medium, etc.
  • Patent Document 1 discloses a method of foreign object detection in the WPC standard.
  • Patent Document 2 discloses a foreign object detection method based on a change in energy attenuation or a change in resonant frequency of a power transmission coil and a resonant circuit integrated or coupled with the power transmission coil.
  • a power transmission device When a power transmission device has multiple power transmission coils in its housing, it is possible to transmit power to multiple power receiving devices. It is also possible to select two or more power transmission coils and manage them collectively to transmit power to a power receiving device that has a single power receiving coil. In the following, the two or more selected power transmission coils are referred to as a "power transmission coil group.”
  • a power transmission method using a power transmission coil group can maintain high power transmission efficiency for a power receiving device with a single power receiving coil, even if a position shift occurs.
  • Patent document 3 discloses a technology for generating a comprehensive quality index based on quality indexes obtained individually from multiple power transmission coils during power transmission, and determining the presence or absence of a foreign object.
  • the method of detecting foreign objects based on the measurement results of the attenuation state of the transmitted radio wave will be referred to below as "foreign object detection using the waveform attenuation method.”
  • foreign object detection using the waveform attenuation method there has been no established method that can optimally perform foreign object detection using the waveform attenuation method when a power transmitting device is transmitting power to a power receiving device using a power transmitting coil group while complying with existing standards (such as the WPC standards).
  • One of the objectives of the present disclosure is to provide a power transmission device that has multiple power transmission coils and can wirelessly transmit power to a power receiving device having a power receiving coil, while detecting foreign objects using a waveform attenuation method for each power transmission coil.
  • the power transmission device disclosed herein includes a power transmission means for wirelessly transmitting power to a power receiving device using multiple power transmission coils, a detection means for detecting the power receiving device or an object different from the power receiving device, a communication means for communicating with the power receiving device, and a control means for controlling the power transmission performed by the power transmission means using multiple selected power transmission coils.
  • the control means controls to limit the power transmission by the selected multiple power transmission coils and to obtain the detection results for the object corresponding to each of the selected multiple power transmission coils using an index representing the attenuation state measured for each power transmission coil.
  • a power transmission device having multiple power transmission coils can wirelessly transmit power to a power receiving device having a power receiving coil, while detecting foreign objects using the waveform attenuation method for each power transmission coil.
  • FIG. 1 is a diagram illustrating a configuration example of a wireless power transmission system. This is an explanatory diagram of a threshold setting method for detecting foreign objects using the Power Loss method.
  • FIG. 2 is a diagram illustrating a configuration example of a power transmitting device.
  • FIG. 2 illustrates an example of the configuration of a power receiving device.
  • 4 is a block diagram showing an example of a functional configuration of a control unit of the power transmitting device.
  • FIG. FIG. 11 is a sequence diagram illustrating an example of a process for performing wireless power transmission.
  • 5A to 5C are explanatory diagrams relating to a form of power transmission by a power transmission coil group.
  • FIG. 13 is an explanatory diagram of foreign object detection using a waveform attenuation method.
  • FIG. 10A and 10B are diagrams illustrating a method for detecting a foreign object based on a power transmission waveform during power transmission.
  • 11 is an explanatory diagram of a threshold setting method in foreign object detection using a waveform attenuation method.
  • FIG. 13A and 13B are diagrams illustrating a method for measuring an indicator of the coupling state between a transmitting antenna and a receiving antenna.
  • 4 is a flowchart of a process performed by a power transmitting device in the first embodiment. 4 is a flowchart of a process performed by a power receiving device according to an embodiment.
  • 10 is a flowchart of a process performed by a power transmitting device according to a second embodiment.
  • FIG. 1 shows an example of the configuration of a wireless power transmission system (wireless charging system) in this embodiment.
  • This system includes a power receiving device 401 and a power transmitting device 402. Detailed configurations of the power receiving device 401 and the power transmitting device 402 will be described later.
  • the power receiving device 401 may be referred to as RX
  • the power transmitting device 402 may be referred to as TX.
  • RX is an electronic device that receives power from TX and charges its built-in battery.
  • TX is an electronic device that wirelessly transmits power to RX placed on charging stand 403. Because charging stand 403 is part of TX, hereinafter "placed on charging stand 403" may be referred to as “placed on TX.”
  • the range indicated by dotted line 404 is the range in which RX can receive power from TX.
  • RX and TX may have the function of executing applications other than wireless charging.
  • RX is a smartphone and TX is an accessory device for charging the smartphone.
  • RX and TX may be a tablet device, a hard disk device, a memory device, etc., or an information processing device such as a personal computer (PC).
  • PC personal computer
  • RX and TX may also be imaging devices such as still cameras and video cameras. Based on the WPC standard, RX and TX perform wireless power transmission using an electromagnetic induction method for wireless charging via the RX receiving antenna and the TX transmitting antenna.
  • the wireless power transmission method applied to this system is not limited to the method specified by the WPC standard, but may be other electromagnetic induction methods, magnetic field resonance methods, electric field resonance methods, microwave methods, laser methods, etc. Also, in this embodiment, wireless power transmission is used for wireless charging, but wireless power transmission may be performed for purposes other than wireless charging.
  • the GP value is a power value that guarantees output to the load (e.g., charging circuit, battery, etc.) of the power receiving device 401 even if the positional relationship between the power receiving device 401 and the power transmitting device 402 changes and the power transmission efficiency between the power receiving antenna and the power transmitting antenna decreases.
  • the power transmitting device 402 performs control to transmit power so that 5 watts can be output to the load in the power receiving device 401.
  • the GP is agreed upon by negotiation between the power transmitting device 402 and the power receiving device 401. Note that this embodiment can be applied to a configuration in which power is transmitted and received at a power determined by mutual negotiation between the power transmitting device and the power receiving device, not limited to the GP.
  • the power transmitting device 402 transmits power to the power receiving device 401
  • an object also called a foreign object
  • the WPC standard specifies a method for the power transmitting device 402 to detect the presence of a foreign object on the charging stand 403.
  • a power loss method is prescribed that detects a foreign object based on the difference between the power transmitted by the power transmitting device 402 and the power received by the power receiving device 401.
  • a Q-factor measurement method is prescribed that detects a foreign object based on changes in the quality factor (Q-factor) of the power transmitting antenna (power transmitting coil).
  • the foreign object that can be detected by the power transmission device 402 in this embodiment is not limited to an object present on the charging stand 403.
  • the power transmission device 402 is capable of detecting a foreign object located in the vicinity of the power transmission device 402.
  • the power transmission device 402 is capable of detecting a foreign object located within a range where power can be transmitted.
  • a foreign object in this disclosure is, for example, a paperclip, an IC card, etc.
  • a foreign object is an object that is neither a power receiving device nor a part of a product in which the power receiving device is incorporated, nor a power transmitting device nor a part of a product in which the power transmitting device is incorporated, and that may generate heat when exposed to the power signal transmitted by the power transmitting antenna.
  • An object that is an integral part of a power receiving device nor a product in which the power receiving device is incorporated, nor a power transmitting device nor an integral part of a product in which the power transmitting device is incorporated, is not considered a foreign object.
  • the horizontal axis represents the transmitted power of the power transmitting device 402
  • the vertical axis represents the received power of the power receiving device 401.
  • point 800 corresponds to the first transmitted power value Pt1 and the first received power value Pr1
  • point 801 corresponds to the second transmitted power value Pt2 and the second received power value Pr2.
  • point 803 corresponds to the third transmitted power value Pt3 and the third received power value Pr3.
  • the foreign object to be detected is an object other than the power receiving device 401 that may affect the power transmission from the power transmitting device 402 to the power receiving device 401, such as an object such as a metal piece that has conductivity.
  • the power transmitting device 402 transmits power to the power receiving device 401 at the first transmission power value Pt1.
  • the power receiving device 401 receives power at the first receiving power value Pr1. This state is called a light load state.
  • the power transmitting device 402 stores the first transmission power value Pt1.
  • the first transmission power value Pt1 and the first reception power value Pr1 are predetermined minimum transmission power values and reception power values.
  • the power receiving device 401 controls the load so that the reception power becomes the minimum power. For example, the power receiving device 401 may disconnect the load from the power receiving antenna 205 so that the reception power is not supplied to the load (such as a charging circuit and a battery).
  • the power receiving device 401 notifies the power transmitting device 402 of the first received power value Pr1.
  • a point 800 is generated, which is a calibration point (hereinafter referred to as CP) that indicates the correspondence between Pt1 and Pr1.
  • the power transmitting device 402 changes the transmission power value to the second transmission power value Pt2 and transmits power to the power receiving device 401.
  • the power receiving device 401 receives power at the second receiving power value Pr2. This state is called a Connected Load state.
  • the power transmitting device 402 then stores the second transmission power value Pt2.
  • the second transmission power value Pt2 and the second reception power value Pr2 are the maximum transmission power value and reception power value that have been determined in advance.
  • the power receiving device 401 controls the load so that the received power becomes the maximum power. For example, the power receiving device 401 connects the receiving antenna to the load so that the received power is supplied to the load.
  • the power receiving device 401 notifies the power transmitting device 402 of the second received power value Pr2.
  • a point 801 is generated, which is a CP that indicates the correspondence between Pt2 and Pr2.
  • the power transmitting device 402 performs linear interpolation between CP800 and CP801 to generate line segment 802.
  • Line segment 802 shows the relationship between the transmitted power and the received power in a state where no foreign object is present near the power transmitting device 402 and the power receiving device 401.
  • power transmission device 402 can estimate the power value received by power receiving device 401 when transmitting power at a specified transmission power in a state in which no foreign object is present. For example, when power transmission device 402 transmits power at a third transmission power value Pt3, it is possible to estimate a third receiving power value Pr3 received by power receiving device 401 from point 803 on line segment 802 that corresponds to Pt3.
  • the power loss between the power transmitting device 402 and the power receiving device 401 according to the load can be obtained based on multiple combinations of the transmitted power value and the received power value measured while changing the load.
  • the power loss between the power transmitting device 402 and the power receiving device 401 according to all loads can be estimated by interpolating from the multiple combinations.
  • the calibration process performed by the power transmitting device 402 and the power receiving device 401 to obtain multiple combinations of transmitted power values and received power values is hereinafter referred to as "Power Loss method calibration process.”
  • the calibration process is referred to as CAL process.
  • the power transmitting device 402 transmits power to the power receiving device 401 at the third transmission power value Pt3, and the power transmitting device 402 acquires the received power value Pr3 * from the power receiving device 401.
  • Ploss_FO is considered to be the power loss due to the power consumed by a foreign object when a foreign object is present near the power transmitting device 402 and the power receiving device 401. Therefore, when the power Ploss_FO that would have been consumed by the foreign object exceeds a predetermined threshold, the power transmitting device 402 can determine that a foreign object is present.
  • Ploss_FO the power Ploss_FO that would have been consumed by the foreign object can be estimated.
  • the power transmitting apparatus 402 After obtaining the line segment 802 by the CAL process of the Power Loss method, the power transmitting apparatus 402 periodically obtains a received power value (for example, the above-mentioned Pr3 * ) from the power receiving apparatus 401.
  • the power receiving apparatus 401 transmits this received power value to the power transmitting apparatus 402 by a Received Power Data Packet (mode 0).
  • the power transmitting device 402 performs foreign object detection based on the received power value stored in the Received Power Data Packet (mode 0) and the line segment 802. Note that Received Power Data Packet (mode 0) is abbreviated as "RP0" below.
  • Foreign object detection using the Power Loss method is performed during power transmission (Power Transfer Phase) based on data acquired in the Calibration Phase.
  • Foreign object detection using the Q-value measurement method is performed before power transmission (before sending a Digital Ping, during the Negotiation Phase or Renegotiation Phase).
  • the RX and TX communicate for power transmission and reception control based on the WPC standard.
  • the WPC standard specifies multiple phases, including a Power Transfer Phase in which power transmission is performed, and one or more phases before the actual power transmission. In each phase, communication is performed for the necessary power transmission and reception control.
  • the phases before power transmission are the Selection Phase, the Ping Phase, and the Identification and Configuration Phase. There are also the negotiation Phase and the Calibration Phase. In the following, the Identification and Configuration Phase is referred to as the I&C Phase. The processing of each phase is explained below.
  • the TX transmits Analog Pings intermittently to detect that an object has been placed on the TX's charging base. For example, it detects that an RX or a piece of conductor has been placed on the charging base.
  • Analog Pings are abbreviated as AP.
  • the TX detects the voltage value or current value, or both, of the transmitting antenna when the AP is transmitted. If the voltage value falls below the threshold value or the current value exceeds the threshold value, the TX determines that an object is present and transitions to the Ping Phase.
  • the TX transmits a Digital Ping with a higher power than the AP.
  • Digital Ping is abbreviated as DP.
  • the power of the DP is sufficient to start up the control unit of the RX placed on the TX.
  • the RX notifies the TX of the magnitude of the received voltage.
  • the TX recognizes that the object detected in the Selection Phase is the RX.
  • the TX is notified of the received voltage value, it transitions to the I&C Phase.
  • the TX measures the Q-factor of the transmitting antenna. The measurement result is used when executing the foreign object detection process using the Q-factor measurement method.
  • the TX identifies the RX and obtains device configuration information (capability information) from the RX.
  • the RX transmits an ID Data Packet and a Configuration Data Packet.
  • the ID Data Packet contains the RX's identifier information
  • the Configuration Data Packet contains the RX's device configuration information.
  • the TX After receiving the ID Data Packet and Configuration Data Packet, the TX sends an acknowledgement (ACK) to the RX as a positive response. Then, the I&C Phase ends.
  • ACK acknowledgement
  • the GP value is determined based on the power requirement value requested by the RX, the transmission capability of the TX, the allowable power, etc.
  • the TX also receives an FOD Status Data Packet containing information on the Reference Quality Factor Value from the RX, and adjusts and determines the threshold value in the Q-value measurement method.
  • the WPC standard also prescribes a method of transitioning to the Power Transfer Phase once, and then performing processing similar to the Negotiation Phase again at the request of the RX.
  • the phase in which this processing is performed after transitioning from the Power Transfer Phase is called the Renegotiation Phase.
  • the RX notifies the TX of a specified received power value (the received power value in a light load state or a maximum load state), and the TX makes adjustments to transmit power efficiently.
  • the received power value notified from the RX to the TX can be used to detect foreign objects using the Power Loss method.
  • the TX and RX use wireless power transmission antennas (power transmitting antenna and power receiving antenna) to superimpose signals onto electromagnetic waves and perform publicly known communication based on the WPC standard. Note that the range in which communication based on the WPC standard is possible between the TX and RX is the same as the range in which the TX can transmit power.
  • TX the power transmitting device 402
  • RX the power receiving device 401
  • FIG. 3 is a functional block diagram showing an example of the configuration of a power transmission device 402 (TX).
  • the TX has a control unit 101, a power supply unit 102, a power transmission unit 103, a communication unit 104, a power transmission antenna 105, a memory 106, a resonant capacitor 107, and a switch unit 108.
  • the control unit 101, power supply unit 102, power transmission unit 103, communication unit 104, and memory 106 are shown as separate entities, but any number of functional block elements may be implemented within the same chip.
  • the control unit 101 controls the entire TX, for example, by executing a control program stored in the memory 106.
  • the control unit 101 also performs control related to power transmission, including communication for device authentication in the TX. Furthermore, the control unit 101 can perform control for executing applications other than wireless power transmission.
  • the control unit 101 includes one or more processors, such as a CPU (Central Processing Unit) or an MPU (Microprocessor Unit). Alternatively, the control unit 101 may be configured with hardware, such as an application specific integrated circuit (ASIC).
  • processors such as a CPU (Central Processing Unit) or an MPU (Microprocessor Unit).
  • MPU Microprocessor Unit
  • the control unit 101 may be configured with hardware, such as an application specific integrated circuit (ASIC).
  • ASIC application specific integrated circuit
  • the control unit 101 may also be configured to include an array circuit such as an FPGA (Field Programmable Gate Array) compiled to execute a specified process.
  • the control unit 101 can execute a process of storing information to be stored in the memory 106 during execution of various processes, and a time measurement process using a timer (not shown).
  • the power supply unit 102 supplies power to each functional block element.
  • the power supply unit 102 includes, for example, a power supply connection circuit to a commercial power source and a battery.
  • the battery is charged with power supplied from the commercial power source.
  • the power transmission unit 103 converts the DC or AC power input from the power supply unit 102 into AC power in the frequency band used for wireless power transmission, and inputs the AC power to the power transmission antenna 105, thereby generating electromagnetic waves for the RX to receive power.
  • the power transmission unit 103 includes an inverter and converts the DC voltage supplied by the power supply unit 102 into an AC voltage using a switching circuit with a half-bridge or full-bridge configuration.
  • the power transmission unit 103 includes multiple FETs (Field Effect Transistors) that form a bridge, and a gate driver that controls the ON/OFF of the multiple FETs.
  • FETs Field Effect Transistors
  • the power transmitting unit 103 controls the intensity of the electromagnetic waves to be output by adjusting the voltage (power transmission voltage) or current (power transmission current), or both, input to the power transmitting antenna 105.
  • the strength of the electromagnetic waves is controlled by the magnitude of the power transmission voltage or power transmission current.
  • the power transmission unit 103 output control of AC frequency power is performed so that the power transmission by the power transmission antenna 105 is started or stopped, or the intensity of the electromagnetic waves to be output is controlled based on an instruction signal from the control unit 101.
  • the power transmission unit 103 has a power supply capacity of outputting 15 watts (W) of power to the charging unit (206 in FIG. 4) of the power receiving device 401 that complies with the WPC standard.
  • the communication unit 104 is connected to the control unit 101 and the power transmitting unit 103, and performs communication with the RX for power transmission control based on the WPC standard.
  • the communication unit 104 performs frequency shift keying of the electromagnetic waves output from the power transmitting antenna 105, and transmits information to the RX to perform communication.
  • the communication unit 104 also demodulates the electromagnetic waves transmitted from the power transmitting antenna 105 that have been amplitude modulated or load modulated by the RX, and acquires the information transmitted by the RX.
  • communication by the communication unit 104 is performed by superimposing a communication signal on the electromagnetic waves transmitted from the power transmitting antenna 105.
  • the communication unit 104 may use an antenna other than the power transmitting antenna 105 and communicate with the RX in accordance with a standard other than the WPC standard.
  • the TX may selectively use multiple communication standards to communicate with the RX.
  • Examples of such communication standards include Bluetooth (registered trademark) Low Energy (BLE) and NFC (Near Field Communication).
  • the memory 106 can store information relating to the TX and RX states.
  • Information relating to the TX and RX states includes the transmitted power value, the received power value, etc.
  • Information relating to the TX state is acquired by the control unit 101.
  • Information relating to the RX state is acquired by the RX control unit (201 in Figure 4) and can be received by the communication unit 104.
  • each unit including the power transmitting antenna 105, resonant capacitor 107, and switch section 108 has the same configuration, only one of them will be explained.
  • the switch section 108 is connected in parallel to the series circuit of the resonant capacitor 107 and the power transmitting antenna 105.
  • the control section 101 transmits a control signal to the switch section 108 to control its ON/OFF.
  • the power transmitting antenna 105 is connected to the resonant capacitor 107.
  • the switch unit 108 When the switch unit 108 is turned ON and short-circuited by a control signal from the control unit 101, the power transmitting antenna 105 and resonant capacitor 107 form a series resonant circuit and resonate at a specific frequency f1. At this time, current flows through the closed circuit formed by the power transmitting antenna 105, resonant capacitor 107, and switch unit 108. On the other hand, when the switch unit 108 is turned OFF by a control signal from the control unit 101 and the circuit is opened, power is supplied from the power transmitting unit 103 to the power transmitting antenna 105 and resonant capacitor 107.
  • the power transmission device of this embodiment is configured with a group of power transmission antennas, each of which is a set of a power transmission antenna (power transmission coil) 105, a resonant capacitor 107, and a switch section 108. Power can be transmitted to multiple power receiving devices simultaneously using multiple power transmission antennas. It is also possible to transmit power to a single power receiving device using multiple power transmission antennas.
  • one control port from the control unit 101 is connected to all switch units 108. This makes it possible to control all switch units 108 simultaneously. It is also possible to control the switch units 108 individually. For example, each switch unit 108 is assigned a unique address.
  • the control unit 101 can specify the destination of the control signal and control the desired switch unit 108.
  • the TX is configured to have a single power transmission unit 103, but there are also configurations with multiple power transmission units 103. At least one of the multiple power transmission units 103 is connected to one or multiple power transmission antennas and can transmit power from the corresponding power transmission antennas. In either configuration, the control unit 101 can control power transmission by the power transmission coil group.
  • FIG. 4 is a block diagram showing an example of the configuration of a power receiving device 401 (RX).
  • the RX has a control unit 201, a UI (user interface) unit 202, a power receiving unit 203, a communication unit 204, a power receiving antenna 205, a charging unit 206, a battery 207, and a memory 208.
  • the RX further has a first switch unit 209, a second switch unit 210, and a resonant capacitor 211.
  • the functional block elements in FIG. 4 are individual elements, but multiple functional block elements may be realized as a single hardware module.
  • the control unit 201 controls each functional block element of the RX by executing a control program stored in the memory 208.
  • the control unit 201 can perform control to execute applications other than wireless power transmission.
  • the control unit 201 includes one or more processors such as a CPU or MPU.
  • control unit 201 can control the entire RX (e.g., the entire smartphone) in cooperation with the OS (Operating System) being executed.
  • the control unit 201 is configured with hardware such as an ASIC, or includes an array circuit such as an FPGA compiled to execute a specified process.
  • the control unit 201 stores information to be stored during the execution of various processes in the memory 208, and is also capable of executing timing processes using a timer (not shown).
  • the UI unit 202 is connected to the control unit 201 and performs various outputs to the user.
  • the various outputs include screen display, blinking or color changes of LEDs (Light Emitting Diodes), audio output from a speaker, vibration of the RX main unit, and other operations.
  • the UI unit 202 is realized by an LCD panel, a speaker, a vibration motor, etc.
  • the power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction based on electromagnetic waves radiated from the TX power transmitting antenna 105 via the power receiving antenna 205.
  • the power receiving unit 203 then converts the AC power into DC or AC power of a specific frequency and supplies the power to the charging unit 206.
  • the charging unit 206 charges the battery 207.
  • the power receiving unit 203 includes a rectifier unit (rectifier, rectifier circuit) and a voltage control unit required for supplying power to the load in RX.
  • the rectifier unit converts the AC voltage and AC current received from the power transmitting antenna via the power receiving antenna 205 into DC voltage and DC current.
  • the voltage control unit converts the level of the DC voltage input from the rectifier unit to a predetermined level.
  • the specified level is a DC voltage level at which the control unit 201, charging unit 206, etc. can operate.
  • the above-mentioned GP is the amount of power guaranteed to be output from the power receiving unit 203.
  • the power receiving unit 203 supplies power for charging the battery 207 from the charging unit 206. It is assumed that the power receiving unit 203 has a power supply capacity sufficient to output 15 watts of power to the charging unit 206.
  • the communication unit 204 communicates with the communication unit 104 of the TX for power reception control based on the WPC standard.
  • the communication unit 204 is connected to the power receiving antenna 205 and the control unit 201.
  • the communication unit 204 demodulates the electromagnetic waves input from the power receiving antenna 205 to obtain the information transmitted from the TX.
  • the communication unit 204 performs load modulation or amplitude modulation of the input electromagnetic waves and superimposes a signal related to information to be transmitted to the TX onto the electromagnetic waves, thereby communicating with the TX.
  • the communication unit 204 may communicate with the TX according to a standard other than the WPC standard using an antenna other than the receiving antenna 205.
  • the communication unit 204 may selectively use the above-mentioned multiple communication standards to communicate with the TX.
  • the memory 208 stores information about the status of the TX and RX.
  • Information about the status of the RX is acquired by the control unit 201.
  • Information about the status of the TX is acquired by the control unit 101 of the TX, and can be received by the communication unit 204.
  • the first switch unit 209 and the second switch unit 210 are controlled by the control unit 201.
  • the first switch unit 209 is provided between the charging unit 206 and the battery 207.
  • the first switch unit 209 has a function of controlling whether or not the power received by the power receiving unit 203 is to be supplied to the battery 207, and a function of controlling the load amount.
  • control unit 201 When the control unit 201 turns the first switch unit 209 to the OFF state and opens it, the power received by the power receiving unit 203 is not supplied to the battery 207. When the control unit 201 turns the first switch unit 209 to the ON state and shorts it, the power received by the power receiving unit 203 is supplied to the battery 207.
  • the first switch unit 209 is disposed between the charging unit 206 and the battery 207, but the first switch unit 209 may be disposed between the power receiving unit 203 and the charging unit 206. Alternatively, the first switch unit 209 may be disposed between the power receiving unit 203 and the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210.
  • the first switch unit 209 has a function of controlling whether or not the power received by the power receiving antenna 205 is supplied to the power receiving unit 203. Also, in the example of FIG. 4, the first switch unit 209 is described as one functional block element, but it is possible to realize the first switch unit 209 as part of the charging unit 206 or the power receiving unit 203.
  • the second switch unit 210 On the input side of the power receiving unit 203, the second switch unit 210 is connected in parallel with the resonant capacitor 211.
  • the power receiving antenna 205 is connected to the resonant capacitor 211, and when the second switch unit 210 is turned on and short-circuited, the power receiving antenna 205 and the resonant capacitor 211 form a series resonant circuit and resonate at a specific frequency f2.
  • FIG. 5 is a block diagram showing an example of the functional configuration of the control unit 101 of the power transmitting device 402 (TX).
  • the control unit 101 has a communication control unit 301, a power transmission control unit 302, a measurement unit 303, a setting unit 304, and a foreign object detection unit 305.
  • the communication control unit 301 controls communication with the RX based on the WPC standard via the communication unit 104.
  • the power transmission control unit 302 controls the power transmission unit 103 to control the power transmission to the RX.
  • the measurement unit 303 measures a waveform attenuation index, which will be described later.
  • the measurement unit 303 also measures the power transmitted to the RX via the power transmission unit 103, and measures the average transmitted power per unit time.
  • the measurement unit 303 also measures the Q value of the power transmission antenna 105.
  • the setting unit 304 calculates and sets a threshold value used for foreign object detection based on the waveform attenuation index measured by the measurement unit 303.
  • the foreign object detection unit 305 executes foreign object detection processing using the power loss method, the Q value measurement method, and the waveform attenuation method.
  • the foreign object detection unit 305 may also execute foreign object detection processing using other methods.
  • the foreign object detection unit 305 can perform foreign object detection processing using the opposing device detection function according to the NFC standard. In addition to the foreign object detection function, the foreign object detection unit 305 can also detect changes in the state of the TX. For example, the TX can detect an increase or decrease in the number of power receiving devices 401 on the TX.
  • NFC Near Field Communication
  • the setting unit 304 sets a threshold value that is a criterion for determining whether or not a foreign object is present, which is necessary for foreign object detection using the power loss method, the Q-value measurement method, and the waveform attenuation method.
  • the setting unit 304 can also set a threshold value that is a criterion for determining whether or not a foreign object is present, which is necessary for foreign object detection processing using other methods.
  • the foreign object detection unit 305 can execute foreign object detection processing based on the waveform attenuation index, transmission power, and Q-value measured by the measurement unit 303.
  • the processes performed by the communication control unit 301, power transmission control unit 302, measurement unit 303, setting unit 304, and foreign object detection unit 305 can be realized using programs executed by a CPU or the like provided in the control unit 101. Each process is executed in parallel according to an independent program, with the programs synchronized by event processing or the like. However, two or more of these processes may be incorporated into the processing of a single program.
  • the WPC standard specifies the Selection Phase, Ping Phase, I&C Phase, Negotiation Phase, Calibration Phase, and Power Transfer Phase.
  • the operation of the TX and RX in these phases will be explained below with reference to Figure 6.
  • FIG. 6 is a sequence diagram explaining an example of power transmission according to the WPC standard.
  • the left side shows the operation of the power transmitting device 402 (TX), and the right side shows the operation of the power receiving device 401 (RX).
  • TX repeatedly and intermittently transmits a WPC standard AP to detect an object present within the power transmission range.
  • the TX executes the processes defined as the Selection Phase and Ping Phase, and waits for the RX to be placed on it.
  • the user of the RX brings the RX (e.g., a smartphone) close to the TX in order to charge it.
  • the user places the RX on the charging stand 403.
  • the TX transmits an AP, and at F504, the TX detects the presence of an object within the power transmission range.
  • the TX selects multiple power transmission coils that can transmit power to the RX, and forms a power transmission coil group.
  • FIGS. 7(A) to (C) are diagrams showing power transmission coil groups.
  • FIG. 7(A) shows an example of the configuration of a power transmission device 402 (TX) that implements multiple power transmission coils. Multiple power transmission coils are arranged so as to overlap each other, ensuring a wide range over which power can be transmitted on the TX.
  • FIG. 7(B) is a diagram showing the configuration of a power transmission coil group 1101.
  • the three power transmission coils represented by solid lines indicate the power transmission coil group 1101.
  • TX can group multiple power transmission coils and transmit power simultaneously through the control of the control unit 101, the power transmission unit 103, and the switch unit 108.
  • Figure 7 (C) shows the state in which the power receiving device 401 (RX) approaches the power transmission coil group 1101 ( Figure 6: F502).
  • the power transmission coil group 1101 and the RX are associated with each other.
  • the TX associates the power transmission coil group 1101 with the power receiving device 401 in F505. This relationship makes it possible to transmit power to one RX using the power transmission coil group 1101 in the Power Transfer Phase.
  • the TX measures the Q value of each of the power transmission coils that make up the power transmission coil group 1101 based on the change in AP.
  • the Q value is a value obtained by the Q value measurement method described below, and is used as the reference Q value for foreign object detection using the waveform attenuation method during power transmission.
  • the TX transmits a DP conforming to the WPC standard.
  • the RX receives the DP in F508, it knows that the TX has detected the RX. Furthermore, if there is a specified response to the DP, the TX determines that the detected object is the RX and that the RX has been placed on the charging stand 403.
  • the TX When the TX detects that the RX has been placed, it obtains identification and capability information from the RX at F509 through communication in the I&C Phase defined in the WPC standard.
  • the RX identification information includes the Manufacturer Code and Basic Device ID.
  • the RX capability information includes, for example, the following information:
  • the TX may obtain the identification information and capability information of the RX by a method other than communication in the I&C Phase of the WPC standard.
  • the identification information may also be any other identification information capable of identifying an individual RX, such as a Wireless Power ID.
  • the capability information may include information other than the above.
  • the TX determines the GP value with the RX through communication in the Negotiation Phase defined in the WPC standard. Note that at F510, other methods or protocols for determining the GP value may be adopted.
  • the TX acquires information, for example, in F509, indicating that the RX does not support the Negotiation Phase.
  • the TX After determining the GP value, the TX performs CAL processing of the Power Loss method based on the GP value.
  • the RX transmits information including the received power in a specified state (hereinafter referred to as first reference received power information) to the TX.
  • the specified state is a light load state, such as a load disconnected state or a load state in which the transmitted power is equal to or less than a first threshold.
  • the first reference received power information is the received power information of the RX when the transmission power of the TX is 500 milliwatts.
  • the first reference received power information is information contained in the Received Power Data Packet (mode 1) defined in the WPC standard.
  • mode 1 the Received Power Data Packet
  • this packet will be referred to as "RP1".
  • RP1 Received Power Data Packet
  • it is not limited to RP1, and other messages may be used.
  • the TX determines whether or not to accept the first reference received power information based on the power transmission state of its own device. If the TX accepts the first reference received power information, it transmits an ACK, which is a positive response, to the RX. If the TX does not accept the first reference received power information, it transmits an NAK, which is a negative response, to the RX.
  • the TX transmits an ACK to the RX.
  • the RX receives the ACK from the TX, it performs processing to transmit information including the received power in a predetermined state (hereinafter referred to as second reference received power information) to the TX.
  • the predetermined state is a load connection state, such as a maximum load state or a load state in which the transmitted power is equal to or greater than a second threshold value.
  • the second reference received power information is the RX received power information when the TX transmission power is 5 watts.
  • the second reference received power information is information contained in the Received Power Data Packet (mode 2) defined in the WPC standard. Hereinafter, this packet will be referred to as "RP2.”
  • RX sends a transmission output change instruction including a positive value to TX in order to increase the transmission power to 5 watts.
  • the positive value is represented by the (+) symbol.
  • the TX receives the transmission output change instruction, and if it is possible to increase the transmission power, it performs control to increase the transmission power and transmits an ACK acknowledgement to the RX in F515. In F516, the RX again transmits a transmission output change instruction including a positive value to the TX.
  • the second reference received power information is the received power information when the transmission power of the TX is 5 watts.
  • the TX receives a power increase request from the RX that exceeds 5 watts, the TX transmits a negative response NAK to the instruction to change the transmission output of the RX at F517. This prevents the transmission of power above the specified level.
  • the RX determines that the default transmission power has been reached by receiving a negative response NAK from the TX. At F518, the RX transmits information including the received power in the load connection state to the TX as second reference received power information.
  • the TX can calculate the amount of power loss between the TX and RX in a light load state and a load connected state based on the transmission power value and the received power value included in the first and second reference received power information.
  • the TX can also perform an interpolation process between the power loss amounts in each state and calculate the power loss value between the TX and RX for all possible transmission powers of the TX. In this example, it is possible to calculate the power loss value between the TX and RX in a transmission power range from 500 milliwatts to 5 watts.
  • the TX transmits an ACK acknowledgement to the second reference received power information from the RX, and completes the CAL process.
  • the TX which has determined that it is possible to start charging, starts power transmission processing to the RX, charging of the RX starts. Note that before the power transmission processing starts, the TX and RX perform communication processing for device authentication in F520.
  • the TX and RX determine that they can support a larger GP, they can reset the GP to a larger value, for example 15 watts, in F521.
  • the RX sends a transmission output change instruction including a positive value to the TX in F522 to increase the transmission power to 15 watts.
  • TX sends an ACK (positive response) to the instruction to change the transmission power output.
  • RX again sends an instruction to change the transmission power output, including a positive value, to TX.
  • TX determines that it is not possible to change the transmission power output, and sends a NAK (negative response) to RX.
  • the amount of power loss between the TX and the RX can be calculated for all possible transmission powers of the TX, ranging from 500 milliwatts to 15 watts.
  • the TX transmits an ACK acknowledgement to the third reference received power information from the RX, and completes the CAL process.
  • TX determines that charging can be started, starts power transmission processing to RX, and moves to the Power Transfer Phase.
  • RX makes a request to change the transmission output power including a positive value in F529, and TX sends a negative response NAK to the request in F530.
  • RX makes a request to change the transmission output power including a negative value (indicated by the (-) symbol in the figure), and TX sends a positive response ACK to the request in F532.
  • the TX performs CAL processing in advance and calculates the amount of power loss between the TX and RX in the absence of a foreign object from the difference between the transmitted power and the received power.
  • the calculated value corresponds to the reference power loss amount during normal power transmission (when there is no foreign object). If the power loss amount between the TX and RX measured during power transmission after CAL processing changes from the reference power loss amount to a threshold value or more, the TX determines that there is a "foreign object" or that there is a "high possibility that a foreign object is present.”
  • a foreign object detection method other than the Power Loss method is implemented to improve the accuracy of foreign object detection.
  • the waveform attenuation method is a method for detecting foreign objects based on the attenuation state of the transmitted power waveform, and will be explained using Figure 8.
  • FIG. 8 is a diagram explaining the principle of foreign object detection using the waveform attenuation method.
  • An example of foreign object detection using a power transmission waveform related to power transmission from TX to RX is shown.
  • the horizontal axis is the time axis
  • the vertical axis represents the voltage value or current value.
  • Waveform 600 shows, for example, the change over time in the high-frequency voltage value (hereinafter simply referred to as the voltage value) applied to the power transmission antenna 105 of the TX.
  • the TX which is transmitting power to the RX via the power transmitting antenna 105, stops transmitting power at time T0 .
  • the power supply for power transmission from the power supply unit 102 is stopped.
  • the frequency of the transmitting radio wave is a fixed frequency, for example, between 85 kHz and 205 kHz used in the WPC standard.
  • a point 601 on the waveform 600 is a point on the envelope of the high frequency voltage, and ( T1 , A1 ) indicates that the voltage value at time T1 is A1 .
  • a point 602 on the waveform 600 is a point on the envelope of the high frequency voltage, and ( T2 , A2 ) indicates that the voltage value at time T2 is A2 .
  • the Q factor which represents the quality factor of the power transmitting antenna 105, can be calculated based on the change over time in the voltage value after time T0 .
  • the TX calculates the Q factor using Equation 1 based on the time and voltage value at points 601 and 602 on the envelope of the high frequency voltage, and the frequency f of the high frequency voltage immediately after power transmission is stopped at time T0 .
  • Equation 1 ln represents a natural logarithm function.
  • Q ⁇ f (T 2 - T 1 ) / ln (A 1 / A 2 ) (Equation 1)
  • the Q value decreases when a foreign object is present near TX and RX, because the foreign object causes energy loss. Therefore, when looking at the slope of the attenuation of the voltage value, the slope of the line connecting points 601 and 602 is greater when a foreign object is present than when no foreign object is present. When energy loss occurs due to a foreign object, the attenuation rate of the amplitude of waveform 600 increases.
  • the presence or absence of a foreign object can be determined based on the attenuation state of the voltage value between points 601 and 602. In fact, the presence or absence of a foreign object can be determined by comparing some numerical value that represents the attenuation state. For example, when the determination is made using the Q value, a Q value lower than the reference value means that the waveform attenuation rate (the degree of decrease in the amplitude of the waveform per unit time) is high.
  • the presence or absence of a foreign object can be determined using the voltage value A2 after a predetermined time has elapsed.
  • the presence or absence of a foreign object can be determined using the time ( T2 - T1 ) that has elapsed until the voltage value A1 reaches the predetermined voltage value A2 .
  • the waveform attenuation method it is possible to determine the presence or absence of a foreign object, for example, based on the attenuation state of the waveform during a period when power transmission is stopped.
  • the indices that represent the attenuation state are collectively referred to as "waveform attenuation indices.”
  • the Q value calculated by the above formula 1 is a value that represents the attenuation state of the voltage value related to power transmission, and is included in the "waveform attenuation indices.”
  • each waveform decay index is a value corresponding to the waveform decay rate
  • the waveform decay rate itself may be measured as the waveform decay index.
  • the waveform decay rate is used as the waveform decay index, but the contents of this embodiment can be similarly applied even when other waveform decay indexes are used.
  • the vertical axis in FIG. 8 has been described as the axis representing the voltage value of the high-frequency voltage applied to the power transmitting antenna 105, the vertical axis in FIG. 8 may also represent the current value flowing through the power transmitting antenna 105.
  • the attenuation state of the current value during the power transmission stop period changes depending on the presence or absence of a foreign object. When a foreign object is present, the waveform attenuation rate is higher than when no foreign object is present.
  • a foreign object can be detected by applying the same method as described above to the change over time in the value of the current flowing through the power transmitting antenna 105. That is, the Q value calculated from the current waveform, the slope of the current value attenuation, the current value difference, the current value ratio, the current value absolute value, or the time until the current value reaches a predetermined value, etc., can be used as waveform attenuation indicators to determine the presence or absence of a foreign object and perform foreign object detection.
  • the presence or absence of a foreign object can be determined using an evaluation value calculated from the waveform attenuation index of the voltage value and the waveform attenuation index of the current value. Note that this is not limited to the example of measuring the waveform attenuation index during a period when power transmission is temporarily suspended.
  • the waveform attenuation index may be measured during the period in which the TX temporarily reduces the power supplied from the power supply unit 102 from a predetermined power level to a lower power level.
  • the voltage or current values are measured at two points in time during the period in which the TX limits power transmission, but the voltage or current values may be measured at three or more points in time.
  • Figure 9 shows an example of a transmission waveform, with the horizontal axis representing time and the vertical axis representing the voltage value or current value of the transmission antenna 105.
  • the transmission waveform is not stable, so the RX does not communicate with the TX by amplitude modulation or load modulation.
  • TX does not communicate with RX using frequency shift keying.
  • this period is referred to as the communication prohibition period.
  • TX transmits power to RX.
  • TX transmits power stably to RX.
  • this period is referred to as the power transmission period.
  • the TX When the TX receives a request packet (command) to execute foreign object detection from the RX, it suspends power transmission after a predetermined period of time has elapsed or temporarily reduces the transmission power. Hereinafter, this predetermined period will be referred to as the preparation period.
  • the request packet to execute foreign object detection may be RP0, RP1, or RP2 as described above.
  • the power transmission control unit 302 of the TX stops power transmission or temporarily reduces the transmission power, the amplitude of the transmitted wave attenuates.
  • the TX calculates the waveform attenuation index of the attenuating transmission wave waveform, compares the calculated waveform attenuation index value with a predetermined threshold value, and determines the presence or absence of a foreign object, or the possibility (probability of presence) of a foreign object.
  • Foreign object determination may be performed during the transmission power control period, or may be performed during the communication prohibited period or power transmission period. After the transmission power control period has elapsed, if the result of the foreign object determination indicates that no foreign object is present or that the possibility of a foreign object being present is low, the TX resumes power transmission. Since the transmission waveform is not stable during the transient response period immediately after power transmission is resumed, the communication prohibited period will begin again, and then the power transmission period will begin.
  • the TX repeatedly executes processing from the start of power transmission through the communication prohibition period, power transmission period, and power transmission power control period.
  • the TX compares the value of the waveform attenuation index calculated at a specified timing with a threshold value to determine whether a foreign object is present. Note that during the power transmission power control period, if elements such as the power receiving unit 203, charging unit 206, and battery 207 are connected to the power receiving antenna 205 and resonant capacitor 211 of the power receiving device 401, the waveform attenuation index is affected by the load of these elements.
  • the waveform attenuation index changes depending on the state of the power receiving unit 203, the charging unit 206, and the battery 207. Therefore, it becomes difficult to distinguish whether a large value of the waveform attenuation index is due to the influence of a foreign object or due to a change in the state of the power receiving unit 203, the charging unit 206, the battery 207, etc. Therefore, when detecting a foreign object based on the waveform attenuation index, the RX sets the first switch unit 209 to a disconnected (OFF) state during the preparation period.
  • the RX turns on the second switch unit 210 to short-circuit it, allowing current to flow through the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210. This makes it possible to suppress the influence of the power receiving unit 203, the charging unit 206, and the battery 207.
  • the RX sends a foreign object detection execution packet (command) to the TX, and executes the above process.
  • the RX may transition to a low power consumption mode or control the power consumption to be constant while the first switch unit 209 is turned ON to short circuit and the second switch unit 210 is turned OFF to disconnect.
  • the waveform attenuation index is affected by the fluctuations in power consumption. For this reason, the RX limits (including halting) the operation of software applications, or sets hardware function block elements to a low power consumption mode or a stopped operation mode. By using the waveform attenuation index measured with the RX power consumption suppressed, more accurate foreign object detection is possible.
  • the TX when the TX receives a foreign object detection execution packet (command) from the RX, it turns on the switch unit 108 during the preparation period, shorting it, and causes a current to flow through the closed circuit formed by the power transmitting antenna 105, the resonant capacitor 107, and the switch unit 108.
  • First determination method A method of determining at a predetermined time.
  • Second determination method The TX determines the length of the period to a predetermined time depending on its state and notifies the RX, or the RX determines the length of the period to a predetermined time depending on its state and notifies the TX.
  • Third determination method TX and RX communicate with each other to determine the length of the period.
  • the TX notifies the RX of the maximum time it has determined, and the RX notifies the TX of the minimum time it has determined.
  • the RX (or TX) determines the length of the preparation period within a range set by the TX and RX, and notifies the TX (or RX) of the determined time. By setting the length of the preparation period to an appropriate time, it is possible to suppress waveform disturbance during the transmission power control period.
  • the TX and RX notify each other of their capability information for the transmission power control period that they can support, and can then determine the actual transmission power control period from within the common range of both.
  • the first command is a command to obtain information on the minimum period of transmission power control that the TX can handle.
  • the second command is a command to notify information on the maximum period of transmission power control that the RX can handle.
  • the first and second commands allow the RX and TX to understand each other's capabilities regarding the transmission power control period.
  • the transmission power control period When comparing a first state in which the transmission power is small with a second state in which the transmission power is large, the transmission power control period is shorter in the second state.
  • ringing may occur in the transmission waveform at the timing when power transmission is resumed.
  • one method is to make the transmission power control period longer when the transmission power is high than when it is low.
  • the transmission power control period is set long and the attenuation state of the transmitted radio wave is measured over a long period of time. This makes it possible to achieve more accurate foreign object detection compared to when the transmission power is low.
  • the purpose of the communication prohibition period is to prevent the TX and RX from communicating with each other regarding ringing that occurs after the start or restart of power transmission.
  • the method for determining the communication prohibition period is the same as the first to third determination methods described above. For example, with the third determination method, it is possible to determine the length of the communication prohibition period to be the minimum or maximum time within the range set by the TX and RX through communication.
  • the communication prohibition period is determined to be longer as the transmission power control period becomes longer. As mentioned above, the greater the difference in the transmission power when transmission is resumed, the greater the ringing that occurs. The longer the transmission power control period, the greater the amount of attenuation of the transmitted radio wave.
  • the method for determining the period is the same as the first to third determination methods described above.
  • the TX notifies the RX of the maximum time it has determined, and the RX notifies the TX of the minimum time it has determined.
  • the RX (or TX) determines the length of the power transmission period within a range set by the TX and RX, and notifies the TX (or RX).
  • the higher the transmission power the shorter the transmission period, thereby increasing the number of transmission power control periods within a given time. This increases the number of times the attenuation state of the transmitted radio wave is measured, increasing the opportunities for foreign object detection. This allows for more accurate foreign object detection.
  • the measured value of the waveform attenuation index is compared with a predetermined threshold, and a foreign object can be detected based on the comparison result.
  • the first threshold setting method is a method in which the TX holds a predetermined value as the threshold, which is a common value that does not depend on the RX to which power is transmitted.
  • This threshold is a fixed value, or a variable value determined by the TX depending on the situation. If a foreign object is present, the waveform attenuation rate of the transmission waveform during the transmission power control period increases. Therefore, the value of the waveform attenuation index obtained when no foreign object is present is stored in advance, and this value is set as the threshold. By comparing the measured value of the waveform attenuation index with the threshold, it is possible to determine that "a foreign object is present" or "there is a high possibility that a foreign object is present.”
  • the TX compares the measured Q value with a predetermined threshold value.
  • the threshold value is set based on the measured value when no foreign object is present or on the measured value that takes into account measurement error. If the measured Q value is smaller than the threshold value, it is determined that "foreign object is present” or "there is a high possibility that a foreign object is present.” If the measured Q value is equal to or greater than the threshold value, it is determined that "no foreign object is present" or "there is a low possibility that a foreign object is present.”
  • the second threshold setting method is a method in which the TX adjusts and determines the threshold based on information transmitted from the RX.
  • a notable difference from the first threshold setting method is that the value of the waveform attenuation index may differ depending on the RX that is the target of power transmission and is placed on the TX.
  • the reason is that the electrical characteristics of the RX, which is electromagnetically coupled via the TX's power transmission antenna, affect the value of the waveform attenuation index.
  • the Q value is used as the waveform attenuation index
  • the Q value measured by the TX when no foreign object is present may differ depending on the RX placed on the TX. Therefore, the RX stores Q value information for each TX when placed on the TX in the absence of a foreign object, and notifies the TX of the Q value information.
  • the TX adjusts and determines the threshold for each RX based on the Q value information received from the RX.
  • the TX receives a FOD Status Data Packet containing Reference Quality Factor Value information during the Negotiation Phase, and adjusts and determines the threshold value in the Q-value measurement method.
  • the Reference Quality Factor Value corresponds to the Q value information when the RX is placed on the TX in the absence of any foreign object. Therefore, the TX performs adjustments based on the Reference Quality Factor Value and determines the threshold value for foreign object detection using the waveform attenuation method.
  • the Reference Quality Factor Value transmitted from RX to TX in this Phase is information used for foreign object detection in the Q-value measurement method, which originally measures the Q-value in the frequency domain.
  • the Q-value when used as a waveform attenuation index, the Q-value can be derived in a different way, but the Q-value can also be calculated from the waveform in Figure 8, for example, using the above formula 1, using the waveform attenuation method, which measures the Q-value in the time domain.
  • the Q value threshold of the waveform attenuation method based on the Reference Quality Factor Value.
  • the value of the waveform attenuation index which takes into account a specified value (a value corresponding to the measurement error) for the Reference Quality Factor Value, may be set as the threshold for foreign object determination.
  • the TX sets the Q-value threshold for the waveform attenuation method based on the information already sent from the RX to the TX in the Negotiation Phase, eliminating the need to perform new measurements to set the threshold.
  • the threshold can be set in a shorter time.
  • Foreign object determination based on the measured value of the threshold and Q-value after the setting is as described above.
  • the third threshold setting method is a method in which the TX measures the waveform attenuation index in the absence of foreign objects, and adjusts and determines the threshold based on the information from the measurement results.
  • the value of the waveform attenuation index may differ depending on the transmission power.
  • the TX measures the waveform attenuation index for each transmitted power and adjusts and determines the threshold based on the measurement results, enabling more accurate foreign object detection.
  • FIG. 10 is a diagram for explaining a method for setting a threshold for foreign object determination for each TX transmission power in the waveform attenuation method.
  • the horizontal axis represents the transmission power of the power transmission device, and the vertical axis represents the waveform attenuation index (waveform attenuation rate) of the transmission voltage waveform or transmission current waveform.
  • point 900 corresponds to the transmission power value Pt1 and the waveform attenuation index ⁇ 1
  • point 901 corresponds to the transmission power value Pt2 and the waveform attenuation index ⁇ 2.
  • point 903 corresponds to the transmission power value Pt3 and the waveform attenuation index ⁇ 3.
  • the RX controls the RX so that it is in a light-load state when power is transmitted from the TX.
  • a light-load state either no power is supplied to the RX load, or only power below a threshold is supplied.
  • the transmission power value of the TX in this state is Pt1.
  • the TX stops transmitting power in a light-load state, or reduces the transmission power, and measures the waveform attenuation index ⁇ 1.
  • the TX recognizes the transmission power value Pt1, and stores in memory CP900 that associates the transmission power value Pt1 with the waveform attenuation index ⁇ 1.
  • the RX controls the load connection state.
  • the load connection state is, for example, a state in which, when power is transmitted from the TX, maximum power is supplied to the RX load, or power above a threshold is supplied.
  • the transmission power value of the TX in this state is Pt2.
  • the TX stops transmission while connected to a load, or reduces the transmission power, and measures the waveform attenuation index ⁇ 2.
  • the TX stores in memory CP901, which associates the transmission power value Pt2 with the waveform attenuation index ⁇ 2.
  • the TX generates line segment 902 by linearly interpolating between CP900 and CP901.
  • Line segment 902 shows the relationship between the transmission power and the waveform attenuation index of the transmitted wave when no foreign object is present around the TX and RX.
  • the TX can therefore estimate the waveform attenuation index for each transmission power value in that state based on line segment 902. For example, in the case of a transmission power value Pt3, the waveform attenuation index is estimated to be ⁇ 3 from point 903 on line segment 902 that corresponds to Pt3.
  • the TX can calculate a threshold value for foreign object determination for each transmission power value based on the estimation result.
  • the waveform attenuation index estimated for a certain transmission power value when no foreign object is present can be adjusted by adding a predetermined value (a value corresponding to the measurement error) to the waveform attenuation index, and this can be set as the threshold for determining whether or not a foreign object is present.
  • a predetermined value a value corresponding to the measurement error
  • the CAL processing performed by the power transmitting device 402 and the power receiving device 401 in order for the power transmitting device 402 to obtain a combination of the transmitted power value and the waveform attenuation index is hereinafter referred to as the "CAL processing of the waveform attenuation method.” Note that in the above example, measurements were performed at two points, the transmitted power values Pt1 and Pt2, but to improve accuracy, measurements may be performed at three or more points to calculate the waveform attenuation index for each transmitted power.
  • the RX may control the light load state and the load connection state after notifying the TX. Also, either of the two controls may be performed first.
  • the calculation process of the foreign object determination threshold for each load may be performed in the calibration phase.
  • the TX acquires data required for foreign object detection using the power loss method.
  • the TX acquires data regarding the received power value and power loss of each RX when the RX load state is a light load state and when the RX load state is a load connected state.
  • the measurements of CP900 and CP901 in FIG. 10 may be performed together with the measurement of power loss during the calibration phase when RX is in a light load state and when it is in a load-connected state.
  • the TX when the TX receives a signal having first reference received power information from the RX, in addition to the predetermined processing to be performed in the calibration phase, the TX measures CP900.
  • the first reference received power information is the RP1 information defined in the WPC standard, but other messages may also be used.
  • the TX When the TX receives a signal having second reference received power information from the RX, it measures CP901 in addition to the predetermined processing to be performed in the Calibration Phase.
  • the second reference received power information is the RP2 information defined in the WPC standard, but other messages may be used. Since there is no need to set aside a separate period for measuring CP900 and CP901, the measurements of CP900 and CP901 can be performed in a shorter time.
  • the TX adjusts and sets the threshold value of the waveform attenuation index at each transmission power. For example, when the Q value is used as the waveform attenuation index, the TX compares the measured value of the Q value with the threshold value determined by the above method.
  • thresholds are set for each TX transmission power, enabling more accurate foreign object determination.
  • a method for measuring the electromagnetic coupling state (including the coupling coefficient) between the transmitting antenna and the receiving antenna will be described.
  • An example of a method for measuring an index representing the coupling state (hereinafter, referred to as a coupling state index) will be shown.
  • the first measurement method will be described. In wireless power transmission, power is transmitted by electromagnetically coupling the transmitting antenna 105 and the receiving antenna 205.
  • Factors that can cause the coupling coefficient to decrease include the presence of a foreign object (such as a metal piece) between the power transmitting antenna and the power receiving antenna, or a misalignment between the power transmitting antenna and the power receiving antenna. Alternatively, the distance between the power transmitting antenna and the power receiving antenna may increase. If a foreign object is placed between the power transmitting antenna and the power receiving antenna, heat may be generated in the foreign object.
  • a foreign object such as a metal piece
  • a process is performed to detect the coupling state (including the coupling coefficient) between the power transmitting antenna and the power receiving antenna in order to improve the detection accuracy of foreign objects and the detection accuracy when the misalignment or distance is large.
  • Fig. 11 (A) is an equivalent circuit diagram for explaining the first measurement method.
  • the definitions of various quantities related to the power transmitting antenna (power transmitting coil) on the primary side (TX) are shown below.
  • r1 Winding resistance of the transmitting antenna.
  • L1 Self-inductance of the transmitting antenna.
  • V1 The transmitting voltage (input voltage) across the transmitting antenna, measured by the TX.
  • r2 Winding resistance of the receiving antenna.
  • L2 Self-inductance of the receiving antenna.
  • V2 The receiving voltage (output voltage) across the receiving antenna measured by the RX.
  • the RX When the TX calculates the coupling coefficient k, the RX notifies the TX of the measured receiving voltage V2 and the value of the self-inductance L2 of the receiving antenna that the RX holds in advance.
  • the TX calculates the k value using the measured transmitting voltage V1, the value of the self-inductance L1 of the transmitting antenna that the TX holds in advance, and the receiving voltage V2 and self-inductance L2 values received from the RX.
  • RX can notify TX of a constant calculated using either or both of L1 and L2, and V2, and TX can calculate the k value using the constant and V2 received from RX, and the transmission voltage V1 measured by TX.
  • the TX notifies the RX of the measured transmission voltage V1 and the previously stored value of the self-inductance L1 of the transmission antenna.
  • the RX calculates the k value using the measured receiving voltage V2, the previously stored value of the self-inductance L2 of the receiving antenna, and the values of the transmission voltage V1 and self-inductance L1 received from the TX.
  • the TX can notify the RX of a constant calculated using either or both of L1 and L2, and V1, and the RX can calculate the k value using the constant and V1 received from the TX, and the receiving voltage V2 measured by the RX.
  • the transmission voltage V1 is calculated by the TX actually measuring the voltage applied to the transmission antenna, or by the TX calculating it from the set value of the transmission power. Alternatively, the transmission voltage V1 may be set as the set value of the transmission voltage during transmission. In addition, the transmission voltage V1 applied to the transmission antenna can be calculated from the transmission voltage (denoted as V3) applied to a circuit (e.g., an inverter) in the TX's transmission unit 103 and the voltage across the resonant capacitor 107.
  • a circuit e.g., an inverter
  • the TX may also calculate the transmission voltage V3 from the set value of the transmission power.
  • the TX may actually measure the transmission voltage V3 and the voltage across the resonant capacitor 107, and use these to determine the transmission voltage V1.
  • the RX may control the second switch unit 210 to be turned OFF so that the terminals of the power receiving antenna 205 are in an open state. This makes it possible to put both ends of the power receiving antenna in an open state as shown in FIG. 11(A). Since the first measurement method is not affected by the resonant capacitor 211, the power receiving unit 203, the charging unit 206, and the battery 207, it becomes possible to measure the coupling coefficient k with higher accuracy.
  • the receiving voltage V2 applied to the receiving antenna can be calculated from the receiving voltage (denoted as V4) applied to a circuit (e.g., a rectifier) in the RX receiving unit 203 and the voltage across the resonant capacitor 211.
  • V4 the receiving voltage
  • a circuit e.g., a rectifier
  • the RX may actually measure the receiving voltage V4 and the voltage across the resonant capacitor 211, and use these to determine the receiving voltage V2.
  • the RX may transmit the measured values of the receiving voltage V4 and the voltage across the resonant capacitor 211 to the TX, and the TX may determine the receiving voltage V2, thereby calculating the k value.
  • the RX when the TX or RX performs the first measurement method, the RX may be controlled to be in a light load state or in a load-connected state. By keeping the load state of the RX constant, it becomes possible to measure the coupling coefficient k with higher accuracy.
  • Coupled state indices there are several other quantities that can be used as indices to represent the electromagnetic coupling state between the transmitting antenna and the receiving antenna. In this embodiment, these are collectively referred to as "coupling state indices.” Each coupling state indices has a value that corresponds to the electromagnetic coupling state between the transmitting antenna and the receiving antenna. The contents of this embodiment can also be applied in the same way when other coupling state indices than the coupling coefficient are used.
  • the coupling state indicators include the transmission voltage V3 applied to a circuit (e.g., an inverter) of the power transmitting unit 103 of the TX, and the receiving voltage (denoted as V4) applied to a circuit (e.g., a rectifier) of the power receiving unit 203 of the RX.
  • V3 applied to a circuit
  • V4 applied to a circuit
  • V4 applied to a circuit
  • the coupling state between the transmitting antenna and the receiving antenna can be calculated.
  • the coupling state between the transmitting antenna and the receiving antenna can be calculated using the output voltage (denoted as V5) of a circuit (e.g., a rectifier) in the receiving unit 203 of the RX.
  • the output voltage V5 is the voltage applied to the load (charging unit, battery).
  • the TX notifies the RX of the transmitting voltage V3, and the RX can calculate the coupling state index.
  • the TX notifies the RX of a constant calculated using the electrical characteristics of the transmitting antenna (e.g., L1), and the RX can calculate the coupling state index using the constant.
  • the RX can calculate the coupling state index from the transmitting voltage V3 received from the TX, a constant calculated using the electrical characteristics of the transmitting antenna received from the TX (e.g., L1), and the receiving voltage V4 or output voltage V5 measured by the RX.
  • the RX notifies the TX of the receiving voltage V4 or the output voltage V5, and the TX calculates the coupling state index.
  • the RX notifies the TX of a constant calculated using the electrical characteristics of the receiving antenna (e.g., L2), and the TX can calculate the coupling state index using the constant.
  • the TX can calculate the coupling state index from the receiving voltage V4 or the output voltage V5 received from the RX, a constant calculated using the electrical characteristics of the receiving antenna received from the RX (e.g., L2), and the transmitting voltage V3 measured by the TX.
  • TX and RX exchange information such as the voltage values V1 to V5, the self-inductance values L1 and L2, or constants that represent the electrical characteristics of the transmitting and receiving antennas.
  • the timing of measuring the voltage values and the timing of sending and receiving each piece of information are explained below. Measurement of each voltage value is performed, for example, in the Ping Phase.
  • the TX transmits a DP to the RX. Therefore, any of the voltage values V1, V2, V3, V4, and V5 that are generated when transmitting a DP can be used.
  • the TX and RX measure any of the values V1 to V5 and store and hold the value in memory 106 or memory 208.
  • the TX receives a predetermined packet containing information on the voltage value of V2, V4, or V5 notified by the RX, and stores the information in memory 106.
  • the information contained in the predetermined packet may include not only the receiving voltage of the RX, but also the receiving power, the value of the self-inductance L2, a constant calculated using the electrical characteristics of the receiving antenna, and other information.
  • a Signal Strength Data packet can be used to notify RX information to TX.
  • the specified packet may be an Identification Data packet or an Extended Identification Data packet in the I&C Phase.
  • it may be a Configuration Data packet. Or it may be a packet in the Calibration Phase or Power Transfer Phase. In other words, it may be RP1, RP2, or RP0. Note that this is not limited to the example in which the voltage value generated when the TX transmits a DP is used. Any of the voltage values V1 to V5 generated when the TX transmits an AP in the Selection Phase may be used.
  • the RX may control the switch unit (not shown) provided between the resonant capacitor 211 and the power receiving unit 203 to be turned OFF so that the terminals of the circuit formed by the power receiving antenna 205 and the resonant capacitor 211 are in an open state. This allows the coupling state index to be measured with higher accuracy since the implementation of the first measurement method is not affected by the power receiving unit 203, the charging unit 206, or the battery 207.
  • FIG. 11(B) is an equivalent circuit diagram for explaining the second measurement method.
  • r1, r2 and L1, L2 are the same as in Figure 11(A).
  • the various quantities related to the transmitting antenna (coil) on the primary side (TX) are defined below.
  • V6 Input voltage of the transmitting antenna when the receiving antenna is shorted.
  • V7 Input voltage of the transmitting antenna when the receiving antenna is in an open state.
  • I1 The current flowing through the transmitting antenna when the receiving antenna is shorted.
  • I2 The current flowing through the transmitting antenna when the receiving antenna is in an open state.
  • Lsc in Equation 3 represents the inductance of the power transmitting antenna when both ends of the power receiving antenna are short-circuited.
  • the control unit 201 sets the second switch unit 210 to the ON state (short-circuit state).
  • the Lsc value can be obtained by measuring the inductance value of the power transmitting antenna.
  • the inductance value of the power transmitting antenna can be found from the input voltage V6 and current I1 of the power transmitting antenna.
  • Lopen represents the inductance of the power transmitting antenna when both ends of the power receiving antenna are open.
  • the control unit 201 sets the second switch unit 210 to the OFF state (open state). In this state, the Lopen value can be obtained by measuring the inductance value of the power transmitting antenna.
  • the inductance value of the transmitting antenna can be determined from the input voltage V7 and current I2 of the transmitting antenna.
  • the coupling state index (coupling coefficient) can be determined from the input voltage and current of the transmitting antenna when both ends of the receiving antenna are short-circuited and open.
  • the TX can also calculate the coupling state index based on the transmission voltage and current applied to a circuit (e.g., an inverter) included in the power transmitting unit 103.
  • the input voltages V6 and V7 represent the transmission voltage applied to a circuit (e.g., an inverter) included in the power transmitting unit 103.
  • the input voltages V6 and V7 may also be the voltages applied to both terminals of a series resonant circuit consisting of a power transmitting antenna and a resonant capacitor.
  • the transmission voltage across a circuit (e.g., an inverter) included in the power transmitting unit 103 and the voltage across both ends of the resonant capacitor 107 may be measured, and the voltage across the power transmitting antenna may be calculated from the results.
  • the transmission voltage across a circuit (e.g., an inverter) included in the power transmitting unit 103 and the voltage across both ends of the resonant capacitor 107 may be calculated by the TX from the set value of the transmission power.
  • the current I1 or I2 is not limited to a current flowing through the power transmitting antenna, and may be, for example, a current flowing through a circuit (e.g., an inverter) included in the power transmitting unit 103.
  • a circuit e.g., an inverter
  • the open state and short state of the power receiving antenna have been described as being realized by the control unit 201 through control of the second switch unit 210. These states may also be realized by the power receiving unit 203. Also, instead of the short state, a light load state may be used.
  • the TX can calculate the coupling state index by measuring the input voltages V6 and V7 and the currents I1 and I2. Therefore, information such as the voltage value measured by the RX or the inductance value of the receiving antenna is not required, so there is no need for the RX to notify the TX of this information.
  • the RX when the TX measures the input voltage V6 and the current I1, the RX needs to keep both terminals of the circuit that includes the receiving antenna in SHORT. Also, when the TX measures the input voltage V7 and the current I2, the RX needs to keep both terminals of the circuit that includes the receiving antenna in OPEN.
  • the RX needs to control both terminals of the circuit containing the receiving antenna to a SHORT or OPEN state.
  • the TX decides on the measurement timing and notifies the RX, or the RX decides on the measurement timing and notifies the TX. This notification is performed by communication between the communication unit 104 of the TX and the communication unit 204 of the RX.
  • the input voltages V6, V7 and currents I1, I2 are measured, for example, in the Ping Phase.
  • the TX transmits a DP to the RX. Therefore, the values of V6, V7 and currents I1, I2 generated when the DP is transmitted can be used.
  • the TX acquires the values of V6, V7, I1, and I2, stores them in the memory 106, and calculates the binding state index.
  • the TX is not limited to using the voltage and current values generated when transmitting a DP.
  • the TX may use the values of V6, V7, I1, and I2 generated when transmitting an AP in the Selection Phase.
  • both the first and second measurement methods are applicable to the method of measuring the coupling status index of the transmitting antenna and the receiving antenna.
  • a status determination threshold is set for the coupling status index obtained by the first or second measurement method.
  • the status determination includes a determination regarding the detection of a foreign object between the power transmitting antenna and the power receiving antenna, a determination regarding the detection of a misalignment between the power transmitting antenna and the power receiving antenna, a determination regarding the detection of the separation between the power transmitting antenna and the power receiving antenna, etc.
  • Fig. 12 is a flowchart explaining the processing of the power transmitting device 402 (TX) when performing foreign object detection using the waveform attenuation method during power transmission
  • Fig. 13 is a flowchart explaining the processing of the power receiving device 401 (RX).
  • TX power transmitting device 402
  • RX power receiving device 401
  • TX starts transmitting power to RX using the power transmission coil group.
  • the power transmission control unit 302 controls multiple switch units 108 to transmit power using a selected power transmission coil. For example, power transmission is started in the power transmission coil group 1101 in FIG. 7, and the power transmission control unit 302 sets the switch unit 108 corresponding to a specific power transmission coil to enabled (ON).
  • the TX judges whether or not a message has been received from the RX during the power transmission period.
  • the communication control unit 301 checks the reception information of the communication unit 104. If reception of a message from the RX is confirmed, the TX stores the information of the received message in the memory 106 and proceeds to the processing of S1203. If reception of a message from the RX is not confirmed, the TX repeatedly executes the judgment processing of S1202.
  • TX determines whether the message received from RX is a message requesting execution of foreign object detection.
  • the control unit 101 checks the message information in memory 106 and determines the type of the message.
  • the message requesting execution of foreign object detection can be a Received Power Data Packet (RP packet) of the WPC standard.
  • the RP packet contains information about the power transmission stop time for foreign object detection using the waveform attenuation method. If it is determined in S1203 that a message requesting execution of foreign object detection has been received, the process proceeds to S1204 and foreign object detection using the waveform attenuation method is started. If it is determined in S1203 that the message is not a message requesting execution of foreign object detection, the process proceeds to S1210.
  • the TX sets a power transmission stop time for each power transmission coil of the power transmission coil group 1101 based on the information on the power transmission stop time included in the received request to execute foreign object detection.
  • the power transmission control unit 302 associates each power transmission coil (power transmission antenna) constituting the power transmission coil group 1101 with the power transmission stop time.
  • the TX performs control to stop power transmission at the time set for each power transmission coil in the power transmission coil group 1101.
  • the power transmission control unit 302 controls the switch unit 108 of the power transmission coil (power transmission antenna) to simultaneously stop power transmission by the multiple power transmission coils at the set power transmission stop time.
  • the process proceeds to S1206.
  • the TX measures the attenuation of the waveform (FIG. 8) due to the power transmission being stopped, and performs processing to obtain, for example, the Q value as an index of waveform attenuation.
  • the measurement unit 303 measures the attenuation of the waveform, making it possible to obtain the Q value for each power transmission coil. In other words, the Q value is obtained for all power transmission coils for which power transmission has been stopped.
  • the TX compares the measured Q value for each transmitting coil with a threshold value (reference Q value).
  • the reference Q value is, for example, the Q value acquired in F506 in FIG. 6.
  • the foreign object detection unit 305 compares the reference Q value with the measured Q value acquired in S1206 to detect a foreign object. For each transmitting coil constituting the transmitting coil group 1101, foreign object detection results are acquired for each transmitting coil. Next, the process proceeds to S1208.
  • a process is performed to determine the final foreign object detection result based on the majority rule for the multiple foreign object detection results obtained in S1207.
  • the foreign object detection unit 305 analyzes the multiple foreign object detection results and determines the foreign object detection result with the greatest number as the final foreign object detection result.
  • TX sends a message (hereinafter, "request message") to RX requesting to obtain the foreign object detection result as a response to the request to execute foreign object detection.
  • the request message can be sent to RX by the communication control unit 301 writing the request message to the communication unit 104.
  • "ATN" can be used as a response to the above RP packet.
  • the TX determines whether or not it has received a message from the RX requesting to obtain the foreign object detection result (hereinafter, referred to as an acquisition request message).
  • the control unit 101 can determine the type of message by checking the message in the memory 106.
  • the data stream response of the WPC standard can be used as the message requesting acquisition of the foreign object detection result. If it is determined in S1210 that the acquisition request message has been received, the process proceeds to S1211, and if it is determined that the acquisition request message has not been received, the process proceeds to S1202.
  • TX transmits the foreign object detection result determined in S1208 to RX.
  • the communication control unit 301 generates a message notifying the foreign object detection result held by the foreign object detection unit 305, and writes the message to the communication unit 104, thereby enabling the message to be transmitted to RX.
  • the message notifying the foreign object detection result can use the FOD Status Data Packet of the WPC standard.
  • the process proceeds to S1202.
  • the process shown in FIG. 12 includes a process that is repeatedly executed every time the RX transmits a message requesting the execution of foreign object detection to the TX in the Power Transfer Phase.
  • the RX process will be described with reference to FIG. 13. The following process is repeatedly executed at a predetermined timing in the Power Transfer Phase.
  • the RX starts receiving power in S1302.
  • the power receiving unit 203 receives power from the power receiving antenna 205 and supplies it to the charging unit 206, thereby enabling charging of the battery 207.
  • RX determines whether or not it is time to send a message requesting execution of foreign object detection in the Power Transfer Phase.
  • the control unit 201 can determine the timing of sending the message using a timer or the like. If it is determined that it is time to send a message requesting execution of foreign object detection, the process proceeds to S1304, and if it is determined that it is not time to send the message, the determination process of S1303 is repeated.
  • the RX generates a message requesting execution of foreign object detection and transmits it to the TX.
  • the control unit 201 determines the power transmission stop time to be included in the RP packet, and performs the transmission process by writing the RP packet including the power transmission stop time to the communication unit 204.
  • S1305 RX judges whether or not a response to the request to execute foreign object detection has been received from TX. This can be achieved by the control unit 201 monitoring the communication unit 204. If the response is not received, the judgment process of S1305 is repeated after waiting for a predetermined time. If it is determined that the response has been received, the process proceeds to S1306.
  • RX determines whether or not the above request message (the "ATN" in the RP packet response) has been received from TX. If it is determined that the request message has been received, it proceeds to S1307, and if it is determined that the request message has not been received, it proceeds to S1311.
  • RX transmits a request message (Data Stream Response) for the foreign object detection result to TX.
  • control unit 201 After confirming the message received by communication unit 204, control unit 201 performs transmission processing by writing the request message to communication unit 204.
  • RX determines whether or not a response has been received from TX, similar to S1305. Waiting process is executed until a notification message of the foreign object detection result is sent in S1211 in FIG. 12. If a response is not received from TX, the determination process of S1308 is repeatedly executed. Also, if it is determined that a response has been received from TX, the process proceeds to S1309.
  • RX determines whether or not it has received a foreign object detection result notification message (FOD Status Data Packet) as a response from TX. If it determines that the notification message has been received, it proceeds to S1310, and if it determines that the notification message has not been received, it proceeds to S1312.
  • FOD Status Data Packet foreign object detection result notification message
  • RX obtains the foreign object detection result. This can be achieved by the control unit 201 obtaining the foreign object detection result from the message received by the communication unit 204. Then, the process proceeds to S1303, and RX executes a process to time the next foreign object detection request.
  • RX processes the corresponding message.
  • RX executes the predetermined process corresponding to a message other than a request message in S1311, and then proceeds to S1305.
  • RX executes the predetermined process corresponding to a message other than a foreign object detection result notification message in S1312, and then proceeds to S1308.
  • the TX transmits power to the RX using the power transmission coil group as shown in FIG. 7(C).
  • the RX issues a foreign object detection execution request (RP packet)
  • foreign object detection processing using the waveform attenuation method is executed simultaneously in all the power transmission coils that make up the power transmission coil group.
  • the final foreign object detection result can be obtained by majority voting from the multiple foreign object detection results obtained.
  • the TX can obtain a more accurate foreign object detection result and notify the RX, compared to foreign object detection processing using the waveform attenuation method performed with a single transmitting coil.
  • the RX acquires information indicating the presence of a foreign object in S1310, it transmits a signal to the TX requesting a restriction on power transmission.
  • a restriction on power transmission includes stopping power transmission or reducing the transmission power.
  • the TX performs control to stop power transmission or reduce the transmission power in accordance with the request to limit power transmission. This makes it possible to avoid damage caused by heat generation by the foreign object, etc.
  • a power transmission coil group is configured, and power transmission to a power receiving device having a single power receiving coil can be continued while foreign object detection using the waveform attenuation method can be appropriately performed. This makes it possible to avoid situations caused by foreign objects during power transmission by the power transmission coil group.
  • FIG. 14 is a flowchart explaining the processing performed by the TX.
  • the following processing is repeatedly executed every time the RX sends a request to execute foreign object detection to the TX in the Power Transfer Phase.
  • the processing from S1401 to S1404 is the same as the processing from S1201 to S1204 in FIG. 12, respectively.
  • the process proceeds to S1405, where the TX determines the order of the power transmission coils that will perform foreign object detection using the waveform attenuation method.
  • the TX does not control power simultaneously in multiple power transmission coils for foreign object detection using the waveform attenuation method in a power transmission coil group.
  • the TX performs time-sharing control of multiple power transmission coils and sequentially performs foreign object detection using the waveform attenuation method.
  • the TX determines the execution order for foreign object detection.
  • the execution order can be determined, for example, by the control unit 101 randomly. However, the method is not limited to this, and any method can be used.
  • the process proceeds to S1406.
  • the TX executes power control for the first power transmission coil determined in S1405 to detect a foreign object using the waveform attenuation method.
  • the power transmission control unit 302 can stop power transmission for a set period of time by controlling the switch unit 108 corresponding to the power transmission coil to be controlled.
  • the TX acquires the Q value for the transmitting coil for which power control was performed. Then, in S1408, the TX determines whether or not foreign object detection using the waveform attenuation method has been performed for all target transmitting coils, according to the execution order determined in S1405.
  • the process proceeds to S1409, and if there are any transmitting coils that have not yet been detected, the process proceeds to S1406 and continues with the next specified transmitting coil.
  • foreign object detection using the waveform attenuation method is performed in a time-division manner for all of the power transmission coils that make up the power transmission coil group 1101, and the Q value for each power transmission coil is obtained.
  • the processing from S1409 to S1413 is the same as the processing from S1207 to S1211.
  • the processing performed by the RX is as described in FIG. 13.
  • the TX transmits power to the RX using the power transmission coil group as shown in FIG. 7(C).
  • the TX executes foreign object detection using the waveform attenuation method in a time-division manner for all the power transmission coils that make up the power transmission coil group.
  • the final foreign object detection result can be obtained by majority voting from the multiple foreign object detection results obtained.
  • the TX can obtain a more accurate foreign object detection result and notify the RX.
  • Modification of the second embodiment] 14 a method for randomly determining the execution order of the power transmitting coils related to foreign object detection using the waveform attenuation method in a time division manner has been described.
  • the execution order of the power transmitting coils is determined according to the order of the waveform attenuation indexes (e.g., Q values) related to the power transmitting coils.
  • the measurement unit 303 obtains the Q value for each power transmission coil using a Q value measurement method, and the control unit 101 determines the execution order according to the high or low Q value.
  • Methods for determining the execution order (rank) based on the Q value include a method of giving the highest execution order to the highest Q value, and a method of giving the highest execution order to the lowest Q value.
  • determining the execution order of each transmitting coil according to the order of the coupling state index (e.g., k value) for each transmitting coil.
  • the measurement unit 303 measures the k value for each transmitting coil, and the control unit 101 determines the execution order according to the high or low k value.
  • Methods for determining the execution order (rank) based on the k value include a method of assigning higher execution order to higher k value, or a method of assigning higher execution order to lower k value.
  • foreign object detection using the waveform attenuation method is a process that is executed repeatedly. Therefore, there is a method of determining the execution order of each power transmission coil from the result of foreign object detection using the waveform attenuation method executed a predetermined number of times before the current time (for example, one time before).
  • the method of determining the execution order (rank) based on previously obtained foreign object detection results includes a method of assigning higher execution orders to the results with the highest probability of the presence of a foreign object, and a method of assigning higher execution orders to the results with the lowest probability of the presence of a foreign object.
  • a power transmission coil group 1101 is composed of three power transmission coils as shown in FIG. 7, one or two of the power transmission coils are selected and foreign object detection is performed using the waveform attenuation method.
  • FIG. 12 and 13 A method for selecting a power transmission coil to perform foreign object detection using the waveform attenuation method will be described.
  • the process shown in Figures 12 and 13 is a process that is periodically and repeatedly executed in the Power Transfer Phase. Therefore, it is possible to change the power transmission coil in a rotating manner each time the process is executed.
  • the three power transmission coils that make up the power transmission coil group 1101 are denoted as power transmission coil 1, power transmission coil 2, and power transmission coil 3, respectively.
  • the pair of power transmission coil 1 and power transmission coil 2 is selected, and when the second process is executed, the pair of power transmission coil 2 and power transmission coil 3 is selected.
  • the pair of transmitting coil 3 and transmitting coil 1 is selected.
  • transmitting coil 1, transmitting coil 2, and transmitting coil 3 have all been selected and transmission power control has been performed.
  • the measuring unit 303 acquires Q values using a Q value measurement method.
  • a predetermined number of transmitting coils are selected in descending order of Q value.
  • the Q values associated with N transmitting coils are represented as Qj , where j is a variable representing any natural number from 1 to N.
  • the Qj are sorted in descending order of Q value, and the power transmitting coils corresponding to the top M Qj are selected, and foreign object detection is performed using the power transmitting coils by the waveform attenuation method.
  • the measurement unit 303 measures the k value associated with each transmitting coil.
  • a predetermined number of transmitting coils are selected in descending order of the k value.
  • the k value associated with N transmitting coils is represented as kj , where j is a variable representing any natural number from 1 to N.
  • the kj are sorted in descending order of k value, and the power transmitting coils corresponding to the top M kj are selected, and foreign object detection is performed using the power transmitting coils by the waveform attenuation method.
  • Another method is to select a predetermined number of power transmitting coils from both power transmitting coils whose k value is higher than a threshold value (denoted as ksh) ( kj > ksh) and power transmitting coils whose k value is lower than ksh ( kj ⁇ ksh).
  • the process of selecting a specific power transmission coil is not performed every time, but foreign object detection using the waveform attenuation method is performed on all power transmission coils constituting the power transmission coil group 1101 a predetermined number of times (e.g., once) out of the total number of times.
  • a method is illustrated in which a final foreign object detection result is obtained from the multiple foreign object detection results obtained by majority voting, but this is not limited to this method.
  • the result of foreign object detection using the waveform attenuation method is not the presence or absence of a foreign object, but the probability of the presence of a foreign object.
  • the TX calculates a statistical value of the multiple foreign object detection results obtained and notifies the RX of the statistical value.
  • Statistical values include arithmetic mean, geometric mean, median, mode, etc.
  • the TX can select one from the multiple foreign object detection results obtained and notify the RX.
  • Methods for selecting a foreign object detection result include selecting the highest, lowest, or median probability of the presence of a foreign object.
  • the TX multiplies the value of the foreign object presence probability obtained for each transmitting coil by a waveform attenuation index (e.g., Q value) or a coupling state index (e.g., k value) for each transmitting coil during power transmission.
  • the TX uses the Q value or k value to perform weighting correction before calculating the final foreign object detection result.
  • the foreign object detection result that the TX notifies the RX of is not limited to one. There is a method in which the TX notifies the RX of all foreign object detection results obtained from multiple transmission coils. In this way, there are various methods for determining (confirming) the foreign object detection result that the TX notifies of to the RX. By using an appropriate determination method depending on the wireless power transmission system, it is possible to further improve the accuracy of foreign object detection.
  • the TX controls the transmission power and detects foreign objects using a waveform attenuation index (e.g., Q value).
  • a waveform attenuation index e.g., Q value
  • the TX transmits a signal having multiple frequency components (e.g., a pulse wave), measures the amplitude or attenuation state of the waveform, and measures the Q value by performing arithmetic processing (e.g., Fourier transform) on the measurement results.
  • arithmetic processing e.g., Fourier transform
  • the present disclosure can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program.
  • the present disclosure can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

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Abstract

In the present invention, an electric power transfer device 402 that has a plurality of electric power transfer coils selects a plurality of electric power transfer coils for wirelessly transferring electric power to an electric power reception device 401 in order to wirelessly transfer electric power, using an electric power transfer device that has a plurality of electric power transfer coils, to an electric power receiver that has an electric power reception coil, while detecting foreign objects using waveform attenuation for each electric power transfer coil (detecting foreign objects based on the results from measuring the state of attenuation of an electric power transfer waveform). Prior to initiating electric power transfer, the electric power transfer device 402 acquires waveform attenuation indices regarding the selected electric power transfer coils. The waveform attenuation indices express the state of attenuation of waveforms during a period in which electric power transfer is limited. Additionally, after initiating electric power transfer, the electric power transfer device 402 receives a request for foreign object detection via waveform attenuation from the electric power receiver 401, and performs foreign object detection using the waveform attenuation method via the electric power transfer coils that are transferring electric power. On the basis of the plurality of acquired waveform attenuation indices, the electric power transfer device 402 acquires foreign object detection results that correspond to the number of electric power transfer coils, and controls the electric power transfer.

Description

送電装置およびその制御方法、受電装置、記憶媒体Power transmitting device and control method thereof, power receiving device, and storage medium
　本開示は、無線電力伝送のための送電装置およびその制御方法、受電装置、記憶媒体等に関する。 This disclosure relates to a power transmission device for wireless power transmission, a control method thereof, a power receiving device, a storage medium, etc.
　無線充電の標準化団体Ｗｉｒｅｌｅｓｓ　Ｐｏｗｅｒ　Ｃｏｎｓｏｒｔｉｕｍが策定する規格（以下、ＷＰＣ規格と記す）が知られている。特許文献１には、ＷＰＣ規格における、異物検出（Ｆｏｒｅｉｇｎ　Ｏｂｊｅｃｔ　Ｄｅｔｅｃｔｉｏｎ）の方法が開示されている。また、特許文献２には、送電コイルと、送電コイルと一体化され、または結合された共振回路の、エネルギー減衰の変化または共振周波数の変化に基づく異物検出方法が開示されている。 The standard (hereinafter referred to as the WPC standard) established by the Wireless Power Consortium, a standardization organization for wireless charging, is known. Patent Document 1 discloses a method of foreign object detection in the WPC standard. Patent Document 2 discloses a foreign object detection method based on a change in energy attenuation or a change in resonant frequency of a power transmission coil and a resonant circuit integrated or coupled with the power transmission coil.
　送電装置が、その筐体内に複数の送電コイルを有する構成では、複数の受電装置への送電が可能である。また、２つ以上の送電コイルを選定してまとめて管理し、単一の受電コイルを有する受電装置に送電することも可能である。以下では、選定された２つ以上の送電コイルを、「送電コイルグループ」という。 When a power transmission device has multiple power transmission coils in its housing, it is possible to transmit power to multiple power receiving devices. It is also possible to select two or more power transmission coils and manage them collectively to transmit power to a power receiving device that has a single power receiving coil. In the following, the two or more selected power transmission coils are referred to as a "power transmission coil group."
　送電コイルグループを用いる送電形態は、単一の受電コイルを有する受電装置に対して、位置ずれ等が発生した場合でも高い送電効率を維持することが可能である。送電コイルグループによる送電中に異物検出処理を行う方法がある。特許文献３には、送電中の複数の送電コイルから個別に取得される品質指標に基づき、総合的な品質指標を生成して異物の有無を判定する技術が開示されている。 A power transmission method using a power transmission coil group can maintain high power transmission efficiency for a power receiving device with a single power receiving coil, even if a position shift occurs. There is a method for performing a foreign object detection process during power transmission by a power transmission coil group. Patent document 3 discloses a technology for generating a comprehensive quality index based on quality indexes obtained individually from multiple power transmission coils during power transmission, and determining the presence or absence of a foreign object.
特開２０１７－７００７４号公報JP 2017-70074 A 特開２０１５－２７１７２号公報JP 2015-27172 A 特開２０２０－１１４１７０号公報JP 2020-114170 A
　送電波形の減衰状態の測定結果に基づいて異物検出を行う方法を、以下では「波形減衰法による異物検出」と呼ぶことにする。既存の規格（ＷＰＣ規格等）に準拠しつつ、送電コイルグループを用いて送電装置が受電装置に送電を行っているときに、波形減衰法による異物検出を好適に実施する方法は、これまで確立されていない。 The method of detecting foreign objects based on the measurement results of the attenuation state of the transmitted radio wave will be referred to below as "foreign object detection using the waveform attenuation method." Up until now, there has been no established method that can optimally perform foreign object detection using the waveform attenuation method when a power transmitting device is transmitting power to a power receiving device using a power transmitting coil group while complying with existing standards (such as the WPC standards).
　本開示は、複数の送電コイルを有する送電装置により、受電コイルを有する受電装置に無線で送電しつつ、送電コイルごとの波形減衰法による異物検出を行える送電装置を提供することを目的の一つとする。 One of the objectives of the present disclosure is to provide a power transmission device that has multiple power transmission coils and can wirelessly transmit power to a power receiving device having a power receiving coil, while detecting foreign objects using a waveform attenuation method for each power transmission coil.
　本開示の送電装置は、複数の送電コイルにより無線で受電装置に送電する送電手段と、前記受電装置または前記受電装置とは異なる物体を検出する検出手段と、前記受電装置と通信する通信手段と、選択した複数の送電コイルにより前記送電手段が行う送電を制御する制御手段と、を備える。前記制御手段は、前記送電手段が送電を開始した後に、送電波形の減衰状態に基づく前記物体の検出処理の実行要求を前記通信手段が前記受電装置から受信した場合、選択した前記複数の送電コイルによる送電を制限し、送電コイルごとに測定される前記減衰状態を表す指標を用いて、選択した前記複数の送電コイルにそれぞれ対応する、前記物体の検出結果を取得する制御を行う。 The power transmission device disclosed herein includes a power transmission means for wirelessly transmitting power to a power receiving device using multiple power transmission coils, a detection means for detecting the power receiving device or an object different from the power receiving device, a communication means for communicating with the power receiving device, and a control means for controlling the power transmission performed by the power transmission means using multiple selected power transmission coils. When the communication means receives a request from the power receiving device to execute a detection process for the object based on the attenuation state of the transmitted radio wave after the power transmission means starts transmitting power, the control means controls to limit the power transmission by the selected multiple power transmission coils and to obtain the detection results for the object corresponding to each of the selected multiple power transmission coils using an index representing the attenuation state measured for each power transmission coil.
　本開示によれば、複数の送電コイルを有する送電装置により、受電コイルを有する受電装置に無線で送電しつつ、送電コイルごとの波形減衰法による異物検出を行うことができる。 According to the present disclosure, a power transmission device having multiple power transmission coils can wirelessly transmit power to a power receiving device having a power receiving coil, while detecting foreign objects using the waveform attenuation method for each power transmission coil.
無線電力伝送システムの構成例を示す図である。FIG. 1 is a diagram illustrating a configuration example of a wireless power transmission system. Ｐｏｗｅｒ　Ｌｏｓｓ法による異物検出における閾値設定方法の説明図である。This is an explanatory diagram of a threshold setting method for detecting foreign objects using the Power Loss method. 送電装置の構成例を示す図である。FIG. 2 is a diagram illustrating a configuration example of a power transmitting device. 受電装置の構成例を示す図である。FIG. 2 illustrates an example of the configuration of a power receiving device. 送電装置の制御部の機能構成例を示すブロック図である。4 is a block diagram showing an example of a functional configuration of a control unit of the power transmitting device. FIG. 無線電力伝送を行うための処理例を示すシーケンス図である。FIG. 11 is a sequence diagram illustrating an example of a process for performing wireless power transmission. （Ａ）～（Ｃ）は、送電コイルグループによる送電形態に関する説明図である。5A to 5C are explanatory diagrams relating to a form of power transmission by a power transmission coil group. 波形減衰法による異物検出の説明図である。FIG. 13 is an explanatory diagram of foreign object detection using a waveform attenuation method. 送電中の送電波形に基づく異物検出方法の説明図である。10A and 10B are diagrams illustrating a method for detecting a foreign object based on a power transmission waveform during power transmission. 波形減衰法による異物検出における閾値設定方法の説明図である。11 is an explanatory diagram of a threshold setting method in foreign object detection using a waveform attenuation method. FIG. （Ａ）、（Ｂ）は、送電アンテナと受電アンテナの結合状態指標測定法の説明図である。13A and 13B are diagrams illustrating a method for measuring an indicator of the coupling state between a transmitting antenna and a receiving antenna. 第１実施形態における送電装置が行う処理のフローチャートである。4 is a flowchart of a process performed by a power transmitting device in the first embodiment. 実施形態における受電装置が行う処理のフローチャートである。4 is a flowchart of a process performed by a power receiving device according to an embodiment. 第２実施形態における送電装置が行う処理のフローチャートである。10 is a flowchart of a process performed by a power transmitting device according to a second embodiment.
　以下、本開示の実施形態について、添付図面を参照しつつ詳細に説明する。実施形態では無線電力伝送システムを適用した無線充電システムの一例として、ＷＰＣ規格に基づくシステムを説明する。 Below, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In the embodiment, a system based on the WPC standard will be described as an example of a wireless charging system to which a wireless power transmission system is applied.
［第１実施形態］
　図１は、本実施形態における無線電力伝送システム（無線充電システム）の構成例を示す。本システムは受電装置４０１と送電装置４０２を含んで構成される。受電装置４０１と送電装置４０２の詳細な構成については後述する。以下では、受電装置４０１をＲＸと呼び、送電装置４０２をＴＸと呼ぶ場合がある。 [First embodiment]
1 shows an example of the configuration of a wireless power transmission system (wireless charging system) in this embodiment. This system includes a power receiving device 401 and a power transmitting device 402. Detailed configurations of the power receiving device 401 and the power transmitting device 402 will be described later. Hereinafter, the power receiving device 401 may be referred to as RX, and the power transmitting device 402 may be referred to as TX.
　ＲＸは、ＴＸから受電して内蔵バッテリに充電を行う電子機器である。ＴＸは、充電台４０３に載置されたＲＸに対して無線で送電する電子機器である。充電台４０３はＴＸの一部であるため、以下では「充電台４０３に戴置された」ことを、「ＴＸに載置された」という場合がある。点線４０４に示す範囲は、ＲＸがＴＸから受電が可能な範囲である。 RX is an electronic device that receives power from TX and charges its built-in battery. TX is an electronic device that wirelessly transmits power to RX placed on charging stand 403. Because charging stand 403 is part of TX, hereinafter "placed on charging stand 403" may be referred to as "placed on TX." The range indicated by dotted line 404 is the range in which RX can receive power from TX.
　ＲＸとＴＸは、無線充電以外のアプリケーションを実行する機能を有しうる。例えば、ＲＸはスマートフォンであり、ＴＸはスマートフォンを充電するためのアクセサリ機器である。あるいはＲＸおよびＴＸは、タブレット機器や、ハードディスク装置、メモリ装置等であってもよいし、パーソナルコンピュータ（ＰＣ）等の情報処理装置であってもよい。 RX and TX may have the function of executing applications other than wireless charging. For example, RX is a smartphone and TX is an accessory device for charging the smartphone. Alternatively, RX and TX may be a tablet device, a hard disk device, a memory device, etc., or an information processing device such as a personal computer (PC).
　また、ＲＸおよびＴＸは、スチルカメラやビデオカメラ等の撮像装置であってもよい。ＲＸとＴＸは、ＷＰＣ規格に基づいて、無線充電のための電磁誘導方式を用いた無線電力伝送を、ＲＸの受電アンテナとＴＸの送電アンテナによって行う。 RX and TX may also be imaging devices such as still cameras and video cameras. Based on the WPC standard, RX and TX perform wireless power transmission using an electromagnetic induction method for wireless charging via the RX receiving antenna and the TX transmitting antenna.
　なお、本システムに適用される無線電力伝送方式は、ＷＰＣ規格で規定された方式に限られず、他の電磁誘導方式、磁界共鳴方式、電界共鳴方式、マイクロ波方式、レーザー等を利用した方式であってもよい。また、本実施形態では、無線電力伝送が無線充電に用いられるものとするが、無線充電以外の用途で無線電力伝送が行われてもよい。 The wireless power transmission method applied to this system is not limited to the method specified by the WPC standard, but may be other electromagnetic induction methods, magnetic field resonance methods, electric field resonance methods, microwave methods, laser methods, etc. Also, in this embodiment, wireless power transmission is used for wireless charging, but wireless power transmission may be performed for purposes other than wireless charging.
　ＷＰＣ規格では、受電装置４０１が送電装置４０２から受電する際に保証される電力の大きさが、Ｇｕａｒａｎｔｅｅｄ　Ｐｏｗｅｒ（以下、「ＧＰ」と呼ぶ）によって規定される。ＧＰ値は、受電装置４０１と送電装置４０２との位置関係が変動して受電アンテナと送電アンテナとの間の送電効率が低下したとしても、受電装置４０１の負荷（例えば、充電用回路、バッテリ等）への出力が保証される電力値である。 In the WPC standard, the amount of power guaranteed when the power receiving device 401 receives power from the power transmitting device 402 is specified by the Guaranteed Power (hereafter referred to as "GP"). The GP value is a power value that guarantees output to the load (e.g., charging circuit, battery, etc.) of the power receiving device 401 even if the positional relationship between the power receiving device 401 and the power transmitting device 402 changes and the power transmission efficiency between the power receiving antenna and the power transmitting antenna decreases.
　例えばＧＰ値が５（ワット）の場合、受電アンテナと送電アンテナとの位置関係が変動して送電効率が低下したとしても、送電装置４０２は、受電装置４０１内の負荷へ５ワットを出力することができるように制御して送電を行う。また、ＧＰは送電装置４０２と受電装置４０１とが行う交渉により合意される。なお、ＧＰに限らず、送電装置と受電装置とが互いに交渉を行うことにより決定される電力で送受電が行われる構成において、本実施形態を適用可能である。 For example, if the GP value is 5 (watts), even if the positional relationship between the power receiving antenna and the power transmitting antenna fluctuates and the power transmission efficiency decreases, the power transmitting device 402 performs control to transmit power so that 5 watts can be output to the load in the power receiving device 401. The GP is agreed upon by negotiation between the power transmitting device 402 and the power receiving device 401. Note that this embodiment can be applied to a configuration in which power is transmitted and received at a power determined by mutual negotiation between the power transmitting device and the power receiving device, not limited to the GP.
　また、送電装置４０２が受電装置４０１へ送電を行う際、送電装置４０２の近傍に受電装置４０１ではない物体（異物ともいう）が存在する場合がありうる。送電のための電磁波が異物に影響して異物の温度上昇や破壊を招く可能性がある。そこでＷＰＣ規格では、送電装置４０２が、充電台４０３上に異物が存在することを検出する方法が規定されている。 In addition, when the power transmitting device 402 transmits power to the power receiving device 401, there may be cases where an object (also called a foreign object) other than the power receiving device 401 is present near the power transmitting device 402. There is a possibility that the electromagnetic waves used for power transmission may affect the foreign object, causing it to heat up or be destroyed. Therefore, the WPC standard specifies a method for the power transmitting device 402 to detect the presence of a foreign object on the charging stand 403.
　異物の存在が検出された場合に送電を停止することで、異物の温度上昇や破壊を防止することが可能である。具体的には、送電装置４０２の送電電力と受電装置４０１の受電電力との差分に基づいて異物を検出する、Ｐｏｗｅｒ　Ｌｏｓｓ（パワーロス）法が規定されている。また、送電アンテナ（送電コイル）に係る品質係数（Ｑ値、Ｑファクター）の変化により異物を検出するＱ値計測法が規定されている。 By stopping power transmission when the presence of a foreign object is detected, it is possible to prevent the foreign object from heating up or being destroyed. Specifically, a power loss method is prescribed that detects a foreign object based on the difference between the power transmitted by the power transmitting device 402 and the power received by the power receiving device 401. In addition, a Q-factor measurement method is prescribed that detects a foreign object based on changes in the quality factor (Q-factor) of the power transmitting antenna (power transmitting coil).
　なお、本実施形態における送電装置４０２により検出可能な異物は充電台４０３の上に存在する物体に限定されない。送電装置４０２は、送電装置４０２の近傍に位置する異物の検出が可能である。例えば、送電装置４０２は送電可能な範囲に位置する異物の検出が可能である。本開示における異物とは、例えば、クリップ、またはＩＣカード等である。 Note that the foreign object that can be detected by the power transmission device 402 in this embodiment is not limited to an object present on the charging stand 403. The power transmission device 402 is capable of detecting a foreign object located in the vicinity of the power transmission device 402. For example, the power transmission device 402 is capable of detecting a foreign object located within a range where power can be transmitted. A foreign object in this disclosure is, for example, a paperclip, an IC card, etc.
　異物は、受電装置および受電装置が組み込まれた製品の一部または送電装置および送電装置が組み込まれた製品の一部のいずれでもなく、送電アンテナが送電する電力信号にさらされたときに発熱しうる物体である。受電装置および受電装置が組み込まれた製品に不可欠な部分の物体または送電装置および送電装置が組み込まれた製品に不可欠な部分の物体は、異物には当たらない。 A foreign object is an object that is neither a power receiving device nor a part of a product in which the power receiving device is incorporated, nor a power transmitting device nor a part of a product in which the power transmitting device is incorporated, and that may generate heat when exposed to the power signal transmitted by the power transmitting antenna. An object that is an integral part of a power receiving device nor a product in which the power receiving device is incorporated, nor a power transmitting device nor an integral part of a product in which the power transmitting device is incorporated, is not considered a foreign object.
　図２を参照して、ＷＰＣ規格で規定されているＰｏｗｅｒ　Ｌｏｓｓ法に基づく異物検出について説明する。図２にて横軸は送電装置４０２の送電電力を表し、縦軸は受電装置４０１の受電電力を表す。直線状の線分８０２で示されるグラフ線上にて、点８００は第１送電電力値Ｐｔ１および第１受電電力値Ｐｒ１に対応し、点８０１は第２送電電力値Ｐｔ２および第２受電電力値Ｐｒ２に対応する。 With reference to Figure 2, foreign object detection based on the Power Loss method defined in the WPC standard will be described. In Figure 2, the horizontal axis represents the transmitted power of the power transmitting device 402, and the vertical axis represents the received power of the power receiving device 401. On the graph line represented by the straight line segment 802, point 800 corresponds to the first transmitted power value Pt1 and the first received power value Pr1, and point 801 corresponds to the second transmitted power value Pt2 and the second received power value Pr2.
　当該グラフ線上にて、点８０３は第３送電電力値Ｐｔ３および第３受電電力値Ｐｒ３に対応する。なお、検出対象である異物は、送電装置４０２から受電装置４０１への送電に影響しうる、受電装置４０１以外の物体であり、例えば導電性を有する金属片等の物体である。 On the graph line, point 803 corresponds to the third transmitted power value Pt3 and the third received power value Pr3. The foreign object to be detected is an object other than the power receiving device 401 that may affect the power transmission from the power transmitting device 402 to the power receiving device 401, such as an object such as a metal piece that has conductivity.
　まず、送電装置４０２は受電装置４０１に対して第１送電電力値Ｐｔ１で送電を行う。受電装置４０１は、第１受電電力値Ｐｒ１で受電する。この状態をＬｉｇｈｔ　Ｌｏａｄ状態（軽負荷状態）という。そして、送電装置４０２は第１送電電力値Ｐｔ１を記憶する。 First, the power transmitting device 402 transmits power to the power receiving device 401 at the first transmission power value Pt1. The power receiving device 401 receives power at the first receiving power value Pr1. This state is called a light load state. Then, the power transmitting device 402 stores the first transmission power value Pt1.
　ここで、第１送電電力値Ｐｔ１、第１受電電力値Ｐｒ１は、予め定められた最小の送電電力値、受電電力値である。このとき、受電装置４０１は受電電力が最小の電力となるように負荷を制御する。例えば、受電装置４０１は、受電電力が負荷（充電回路とバッテリ等）に供給されないように、受電アンテナ２０５から負荷を切断してもよい。 Here, the first transmission power value Pt1 and the first reception power value Pr1 are predetermined minimum transmission power values and reception power values. At this time, the power receiving device 401 controls the load so that the reception power becomes the minimum power. For example, the power receiving device 401 may disconnect the load from the power receiving antenna 205 so that the reception power is not supplied to the load (such as a charging circuit and a battery).
　続いて、受電装置４０１は、第１受電電力値Ｐｒ１を送電装置４０２に通知する。送電装置４０２受電装置４０１から第１受電電力値Ｐｒ１を取得して、送電装置４０２と受電装置４０１との間の電力損失をＰｔ１－Ｐｒ１（＝Ｐｌｏｓｓ１）と算出する。Ｐｔ１とＰｒ１との対応を示すキャリブレーションポイント（以下、ＣＰと記す）である点８００が生成される。 Then, the power receiving device 401 notifies the power transmitting device 402 of the first received power value Pr1. The power transmitting device 402 acquires the first received power value Pr1 from the power receiving device 401, and calculates the power loss between the power transmitting device 402 and the power receiving device 401 as Pt1-Pr1 (=Ploss1). A point 800 is generated, which is a calibration point (hereinafter referred to as CP) that indicates the correspondence between Pt1 and Pr1.
　続いて、送電装置４０２は、送電電力値を第２送電電力値Ｐｔ２に変更し、受電装置４０１に対して送電を行う。受電装置４０１は、第２受電電力値Ｐｒ２で受電する。この状態をＣｏｎｎｅｃｔｅｄ　Ｌｏａｄ状態（負荷接続状態）という。そして、送電装置４０２は第２送電電力値Ｐｔ２を記憶する。 Then, the power transmitting device 402 changes the transmission power value to the second transmission power value Pt2 and transmits power to the power receiving device 401. The power receiving device 401 receives power at the second receiving power value Pr2. This state is called a Connected Load state. The power transmitting device 402 then stores the second transmission power value Pt2.
　ここで、第２送電電力値Ｐｔ２、第２受電電力値Ｐｒ２は、予め定められた最大の送電電力値、受電電力値である。このとき、受電装置４０１は受電電力が最大の電力となるように負荷を制御する。例えば、受電装置４０１は、受電した電力が負荷に供給されるように受電アンテナと負荷とを接続する。 Here, the second transmission power value Pt2 and the second reception power value Pr2 are the maximum transmission power value and reception power value that have been determined in advance. At this time, the power receiving device 401 controls the load so that the received power becomes the maximum power. For example, the power receiving device 401 connects the receiving antenna to the load so that the received power is supplied to the load.
　続いて、受電装置４０１は第２受電電力値Ｐｒ２を送電装置４０２に通知する。送電装置４０２は受電装置４０１から第２受電電力値Ｐｒ２を取得して、送電装置４０２と受電装置４０１との間の電力損失をＰｔ２－Ｐｒ２（＝Ｐｌｏｓｓ２）と算出する。Ｐｔ２とＰｒ２との対応を示すＣＰである点８０１が生成される。 Then, the power receiving device 401 notifies the power transmitting device 402 of the second received power value Pr2. The power transmitting device 402 acquires the second received power value Pr2 from the power receiving device 401, and calculates the power loss between the power transmitting device 402 and the power receiving device 401 as Pt2-Pr2 (=Ploss2). A point 801 is generated, which is a CP that indicates the correspondence between Pt2 and Pr2.
　送電装置４０２はＣＰ８００とＣＰ８０１との間の直線補間処理を行って、線分８０２を生成する。線分８０２は、送電装置４０２と受電装置４０１の近傍に異物が存在しない状態における送電電力と受電電力との関係を示している。 The power transmitting device 402 performs linear interpolation between CP800 and CP801 to generate line segment 802. Line segment 802 shows the relationship between the transmitted power and the received power in a state where no foreign object is present near the power transmitting device 402 and the power receiving device 401.
　送電装置４０２は線分８０２に基づき、異物が存在しない状態にて所定の送電電力で送電した場合に受電装置４０１が受電する電力値を推定できる。例えば、送電装置４０２が第３送電電力値Ｐｔ３で送電した場合、線分８０２上のＰｔ３に対応する点８０３から、受電装置４０１が受電する第３受電電力値Ｐｒ３を推定することができる。 Based on line segment 802, power transmission device 402 can estimate the power value received by power receiving device 401 when transmitting power at a specified transmission power in a state in which no foreign object is present. For example, when power transmission device 402 transmits power at a third transmission power value Pt3, it is possible to estimate a third receiving power value Pr3 received by power receiving device 401 from point 803 on line segment 802 that corresponds to Pt3.
　以上のように、負荷を変更しながら測定された送電電力値と受電電力値との複数の組み合わせに基づいて、負荷に応じた送電装置４０２と受電装置４０１との間の電力損失を求めることができる。また、上記複数の組み合わせからの補間により、すべての負荷に応じた送電装置４０２と受電装置４０１との間の電力損失を推定することができる。 As described above, the power loss between the power transmitting device 402 and the power receiving device 401 according to the load can be obtained based on multiple combinations of the transmitted power value and the received power value measured while changing the load. In addition, the power loss between the power transmitting device 402 and the power receiving device 401 according to all loads can be estimated by interpolating from the multiple combinations.
　このように、複数の送電電力値と受電電力値の組み合わせを取得するために送電装置４０２と受電装置４０１とが行うキャリブレーション処理を、以下では「Ｐｏｗｅｒ　Ｌｏｓｓ法のＣａｌｉｂｒａｔｉｏｎ処理」と呼ぶ。以下では、Ｃａｌｉｂｒａｔｉｏｎ処理を、ＣＡＬ処理と表記する。 The calibration process performed by the power transmitting device 402 and the power receiving device 401 to obtain multiple combinations of transmitted power values and received power values is hereinafter referred to as "Power Loss method calibration process." Hereinafter, the calibration process is referred to as CAL process.
　Ｐｏｗｅｒ　Ｌｏｓｓ法のＣＡＬ処理後、送電装置４０２が受電装置４０１に対して第３送電電力値Ｐｔ３で送電し、送電装置４０２が受電装置４０１から受電電力値Ｐｒ３＊を取得した場合を想定する。送電装置４０２は異物が存在しない状態における第３受電電力値Ｐｒ３から、受電電力値Ｐｒ３＊を減算し、Ｐｒ３－Ｐｒ３＊（＝Ｐｌｏｓｓ＿ＦＯ）を算出する。 Assume that after CAL processing of the Power Loss method, the power transmitting device 402 transmits power to the power receiving device 401 at the third transmission power value Pt3, and the power transmitting device 402 acquires the received power value Pr3 * from the power receiving device 401. The power transmitting device 402 subtracts the received power value Pr3 * from the third received power value Pr3 in a state in which no foreign object is present, to calculate Pr3-Pr3 * (=Plus_FO).
　Ｐｌｏｓｓ＿ＦＯは、送電装置４０２と受電装置４０１の近傍に異物が存在する場合に、その異物で消費される電力による電力損失と考えられる。よって、異物で消費されたであろう電力Ｐｌｏｓｓ＿ＦＯが予め決められた閾値を超えた場合、送電装置４０２は異物が存在すると判定することができる。 Ploss_FO is considered to be the power loss due to the power consumed by a foreign object when a foreign object is present near the power transmitting device 402 and the power receiving device 401. Therefore, when the power Ploss_FO that would have been consumed by the foreign object exceeds a predetermined threshold, the power transmitting device 402 can determine that a foreign object is present.
　あるいは、送電装置４０２は、事前に、異物が存在しない状態における第３受電電力値Ｐｒ３から、送電装置４０２と受電装置４０１との間の電力損失Ｐｔ３－Ｐｒ３（＝Ｐｌｏｓｓ３）を求めておく。そして送電装置４０２は、異物が存在する状態にて受電装置４０１から取得した受電電力値Ｐｒ３＊から、異物が存在する状態での送電装置４０２と受電装置４０１との間の電力損失をＰｔ３－Ｐｒ３＊（＝Ｐｌｏｓｓ３＊）と算出する。 Alternatively, the power transmitting device 402 determines in advance the power loss Pt3-Pr3 (=Ploss3) between the power transmitting device 402 and the power receiving device 401 from the third received power value Pr3 in a state where no foreign object is present. Then, the power transmitting device 402 calculates the power loss between the power transmitting device 402 and the power receiving device 401 in a state where a foreign object is present as Pt3-Pr3 * (=Ploss3 * ) from the received power value Pr3 * obtained from the power receiving device 401 in a state where a foreign object is present.
　Ｐｌｏｓｓ３＊－Ｐｌｏｓｓ３＝（Ｐｔ３－Ｐｒ３＊）－（Ｐｔ３－Ｐｒ３）＝Ｐｒ３－Ｐｒ３＊（＝Ｐｌｏｓｓ＿ＦＯ）である。この式を用いて、異物で消費されたであろう電力Ｐｌｏｓｓ＿ＦＯを推定することができる。 Ploss3 * -Ploss3=(Pt3-Pr3 * )-(Pt3-Pr3)=Pr3-Pr3 * (=Ploss_FO). Using this formula, the power Ploss_FO that would have been consumed by the foreign object can be estimated.
　以上のように、電力損失Ｐｌｏｓｓ＿ＦＯの求め方には、Ｐｒ３－Ｐｒ３＊により求める第１の方法と、Ｐｌｏｓｓ３＊－Ｐｌｏｓｓ３により求める第２の方法がある。本開示では、基本的に第２の方法について述べるが、第１の方法においても本実施形態の内容を適用可能である。 As described above, there are two methods for calculating the power loss Ploss_FO: the first method using Pr3-Pr3 * and the second method using Ploss3 * -Ploss3. In this disclosure, the second method is basically described, but the contents of this embodiment can also be applied to the first method.
　Ｐｏｗｅｒ　Ｌｏｓｓ法のＣＡＬ処理による線分８０２の取得後、送電装置４０２は、受電装置４０１から定期的に受電電力値（例えば上記Ｐｒ３＊）を取得する。受電装置４０１は、この受電電力値を、Ｒｅｃｅｉｖｅｄ　Ｐｏｗｅｒ　Ｄａｔａ　Ｐａｃｋｅｔ（ｍｏｄｅ０）により送電装置４０２に送信する。 After obtaining the line segment 802 by the CAL process of the Power Loss method, the power transmitting apparatus 402 periodically obtains a received power value (for example, the above-mentioned Pr3 * ) from the power receiving apparatus 401. The power receiving apparatus 401 transmits this received power value to the power transmitting apparatus 402 by a Received Power Data Packet (mode 0).
　送電装置４０２は、Ｒｅｃｅｉｖｅｄ　Ｐｏｗｅｒ　Ｄａｔａ　Ｐａｃｋｅｔ（ｍｏｄｅ０）に格納されている受電電力値と、線分８０２とに基づいて異物検出を行う。なお、以下では、Ｒｅｃｅｉｖｅｄ　Ｐｏｗｅｒ　Ｄａｔａ　Ｐａｃｋｅｔ（ｍｏｄｅ０）を「ＲＰ０」と略記する。 The power transmitting device 402 performs foreign object detection based on the received power value stored in the Received Power Data Packet (mode 0) and the line segment 802. Note that Received Power Data Packet (mode 0) is abbreviated as "RP0" below.
　Ｐｏｗｅｒ　Ｌｏｓｓ法による異物検出は、Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅにて取得されたデータに基づき、電力伝送（送電）中（Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅ）に実施される。また、Ｑ値計測法による異物検出は、電力伝送前（Ｄｉｇｉｔａｌ　Ｐｉｎｇ送信前、Ｎｅｇｏｔｉａｔｉｏｎ　ＰｈａｓｅまたはＲｅｎｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅ）に実施される。 Foreign object detection using the Power Loss method is performed during power transmission (Power Transfer Phase) based on data acquired in the Calibration Phase. Foreign object detection using the Q-value measurement method is performed before power transmission (before sending a Digital Ping, during the Negotiation Phase or Renegotiation Phase).
　ＲＸとＴＸは、ＷＰＣ規格に基づく送受電制御のための通信を行う。ＷＰＣ規格では、電力伝送が実行されるＰｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅと、実際の電力伝送前の１以上のＰｈａｓｅとを含んだ、複数のＰｈａｓｅが規定されている。各Ｐｈａｓｅにおいて必要な送受電制御のための通信が行われる。 The RX and TX communicate for power transmission and reception control based on the WPC standard. The WPC standard specifies multiple phases, including a Power Transfer Phase in which power transmission is performed, and one or more phases before the actual power transmission. In each phase, communication is performed for the necessary power transmission and reception control.
　電力伝送前のＰｈａｓｅとして、Ｓｅｌｅｃｔｉｏｎ　Ｐｈａｓｅ、Ｐｉｎｇ　Ｐｈａｓｅ、Ｉｄｅｎｔｉｆｉｃａｔｉｏｎ　ａｎｄ　Ｃｏｎｆｉｇｕｒａｔｉｏｎ　Ｐｈａｓｅがある。またＮｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅ、Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅがある。以下では、Ｉｄｅｎｔｉｆｉｃａｔｉｏｎ　ａｎｄ　Ｃｏｎｆｉｇｕｒａｔｉｏｎ　Ｐｈａｓｅを、Ｉ＆Ｃ　Ｐｈａｓｅと表記する。以下、各Ｐｈａｓｅの処理について説明する。 The phases before power transmission are the Selection Phase, the Ping Phase, and the Identification and Configuration Phase. There are also the Negotiation Phase and the Calibration Phase. In the following, the Identification and Configuration Phase is referred to as the I&C Phase. The processing of each phase is explained below.
　Ｓｅｌｅｃｔｉｏｎ　Ｐｈａｓｅでは、ＴＸがＡｎａｌｏｇ　Ｐｉｎｇを間欠的に送信し、物体がＴＸの充電台に載置されたことを検出する。例えば、充電台にＲＸや導体片等が載置されたことが検出される。以下、Ａｎａｌｏｇ　ＰｉｎｇをＡＰと表記する。ＴＸは、ＡＰを送信した時の送電アンテナの電圧値もしくは電流値、またはその両方を検出する。電圧値が閾値を下回る場合、または電流値が閾値を超える場合、ＴＸは物体が存在すると判断し、Ｐｉｎｇ　Ｐｈａｓｅに遷移する。 In the Selection Phase, the TX transmits Analog Pings intermittently to detect that an object has been placed on the TX's charging base. For example, it detects that an RX or a piece of conductor has been placed on the charging base. Hereinafter, Analog Pings are abbreviated as AP. The TX detects the voltage value or current value, or both, of the transmitting antenna when the AP is transmitted. If the voltage value falls below the threshold value or the current value exceeds the threshold value, the TX determines that an object is present and transitions to the Ping Phase.
　Ｐｉｎｇ　Ｐｈａｓｅでは、ＴＸが、ＡＰより電力が大きいＤｉｇｉｔａｌ　Ｐｉｎｇを送信する。以下、Ｄｉｇｉｔａｌ　ＰｉｎｇをＤＰと表記する。ＤＰの電力の大きさは、ＴＸの上に載置されたＲＸの制御部が起動するのに十分な電力である。 In the Ping Phase, the TX transmits a Digital Ping with a higher power than the AP. Hereafter, Digital Ping is abbreviated as DP. The power of the DP is sufficient to start up the control unit of the RX placed on the TX.
　ＲＸは、受電電圧の大きさをＴＸへ通知する。ＴＸはＤＰを受信したＲＸからの応答を受信することにより、Ｓｅｌｅｃｔｉｏｎ　Ｐｈａｓｅにて検出された物体がＲＸであることを認識する。ＴＸが受電電圧値の通知を受けると、Ｉ＆Ｃ　Ｐｈａｓｅに遷移する。また、ＴＸはＤＰの送信前に、送電アンテナのＱ値（Ｑ－Ｆａｃｔｏｒ）を測定する。測定結果は、Ｑ値計測法を用いた異物検出処理を実行する際に使用される。 The RX notifies the TX of the magnitude of the received voltage. By receiving a response from the RX that received the DP, the TX recognizes that the object detected in the Selection Phase is the RX. When the TX is notified of the received voltage value, it transitions to the I&C Phase. In addition, before transmitting the DP, the TX measures the Q-factor of the transmitting antenna. The measurement result is used when executing the foreign object detection process using the Q-factor measurement method.
　Ｉ＆Ｃ　Ｐｈａｓｅでは、ＴＸはＲＸを識別し、ＲＸから機器構成情報（能力情報）を取得する。ＲＸは、ＩＤ　Ｄａｔａ　ＰａｃｋｅｔおよびＣｏｎｆｉｇｕｒａｔｉｏｎ　Ｄａｔａ　Ｐａｃｋｅｔを送信する。ＩＤ　Ｄａｔａ　ＰａｃｋｅｔはＲＸの識別子情報を含み、Ｃｏｎｆｉｇｕｒａｔｉｏｎ　Ｄａｔａ　ＰａｃｋｅｔはＲＸの機器構成情報を含む。 In the I&C Phase, the TX identifies the RX and obtains device configuration information (capability information) from the RX. The RX transmits an ID Data Packet and a Configuration Data Packet. The ID Data Packet contains the RX's identifier information, and the Configuration Data Packet contains the RX's device configuration information.
　ＩＤ　Ｄａｔａ　ＰａｃｋｅｔおよびＣｏｎｆｉｇｕｒａｔｉｏｎ　Ｄａｔａ　Ｐａｃｋｅｔを受信したＴＸは、肯定応答であるアクノリッジ（ＡＣＫ）をＲＸに送信する。そして、Ｉ＆Ｃ　Ｐｈａｓｅが終了する。 After receiving the ID Data Packet and Configuration Data Packet, the TX sends an acknowledgement (ACK) to the RX as a positive response. Then, the I&C Phase ends.
　Ｎｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅでは、ＲＸが要求する要求電力の値やＴＸの送電能力、許容可能な電力等に基づいてＧＰの値が決定される。またＴＸはＲＸから、Ｒｅｆｅｒｅｎｃｅ　Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ　Ｖａｌｕｅの情報を有するＦＯＤ　Ｓｔａｔｕｓ　Ｄａｔａ　Ｐａｃｋｅｔを受信し、Ｑ値計測法における閾値を調整して決定する。 In the Negotiation Phase, the GP value is determined based on the power requirement value requested by the RX, the transmission capability of the TX, the allowable power, etc. The TX also receives an FOD Status Data Packet containing information on the Reference Quality Factor Value from the RX, and adjusts and determines the threshold value in the Q-value measurement method.
　そして、ＴＸはＲＸからの要求に従って、Ｑ値計測法を用いた異物検出処理を実行する。また、ＷＰＣ規格では、一旦Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅに移行した後、ＲＸの要求によって再度Ｎｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅと同様の処理を行う方法が規定されている。Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅから移行してこれらの処理を行うＰｈａｓｅのことを、Ｒｅｎｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅと呼ぶ。 Then, the TX executes foreign object detection processing using the Q-value measurement method in response to a request from the RX. The WPC standard also prescribes a method of transitioning to the Power Transfer Phase once, and then performing processing similar to the Negotiation Phase again at the request of the RX. The phase in which this processing is performed after transitioning from the Power Transfer Phase is called the Renegotiation Phase.
　Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅでは、ＷＰＣ規格に基づくＣＡＬ処理が実行される。また、ＲＸは所定の受電電力値（軽負荷状態または最大負荷状態における受電電力値）をＴＸへ通知し、ＴＸは効率よく送電するための調整を行う。ＲＸからＴＸへ通知された受電電力値は、Ｐｏｗｅｒ　Ｌｏｓｓ法による異物検出に使用されうる。 In the calibration phase, CAL processing based on the WPC standard is performed. In addition, the RX notifies the TX of a specified received power value (the received power value in a light load state or a maximum load state), and the TX makes adjustments to transmit power efficiently. The received power value notified from the RX to the TX can be used to detect foreign objects using the Power Loss method.
　Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅでは、送電の開始、継続、およびエラー処理や、満充電による送電停止等のための制御が行われる。ＴＸとＲＸは送受電制御のために、ＷＰＣ規格に基づき、無線電力伝送用アンテナ（送電アンテナおよび受電アンテナ）を用いて電磁波に信号を重畳して公知の通信を行う。なお、ＴＸとＲＸとの間で、ＷＰＣ規格に基づく通信が可能な範囲は、ＴＸの送電可能範囲と同様である。 In the Power Transfer Phase, control is performed for starting and continuing power transmission, processing errors, and stopping power transmission when the battery is fully charged. To control power transmission and reception, the TX and RX use wireless power transmission antennas (power transmitting antenna and power receiving antenna) to superimpose signals onto electromagnetic waves and perform publicly known communication based on the WPC standard. Note that the range in which communication based on the WPC standard is possible between the TX and RX is the same as the range in which the TX can transmit power.
　続いて、送電装置４０２（ＴＸ）および受電装置４０１（ＲＸ）の構成例について説明する。なお、以下に説明する構成の一部または全部が他の同様の機能を果たす他の構成と置換され、または省略されてもよく、別の構成に追加されてもよい。 Next, an example configuration of the power transmitting device 402 (TX) and the power receiving device 401 (RX) will be described. Note that some or all of the configuration described below may be replaced with another configuration that performs a similar function, may be omitted, or may be added to another configuration.
　１つの機能ブロック要素を複数の機能ブロック要素に分割することや、複数の機能ブロック要素を１つの機能ブロック要素に統合することが可能である。また、機能ブロック要素は、ソフトウェアプログラムの実行により機能が実現されるか、またはその一部または全部がハードウェアにより実現される。 It is possible to divide one function block element into multiple function block elements, or to integrate multiple function block elements into one function block element. In addition, the functions of the function block elements are realized by the execution of a software program, or part or all of the functions are realized by hardware.
　図３は、送電装置４０２（ＴＸ）の構成例を示す機能ブロック図である。ＴＸは、制御部１０１、電源部１０２、送電部１０３、通信部１０４、送電アンテナ１０５、メモリ１０６、共振コンデンサ１０７、スイッチ部１０８を有する。 FIG. 3 is a functional block diagram showing an example of the configuration of a power transmission device 402 (TX). The TX has a control unit 101, a power supply unit 102, a power transmission unit 103, a communication unit 104, a power transmission antenna 105, a memory 106, a resonant capacitor 107, and a switch unit 108.
　複数の送電アンテナ１０５を備える構成にて送電アンテナごとに共振コンデンサ１０７およびスイッチ部１０８を設けた例を示す。図３では制御部１０１、電源部１０２、送電部１０３、通信部１０４、メモリ１０６を別体として記載しているが、任意の複数の機能ブロック要素は、同一チップ内に実装されてもよい。 This shows an example of a configuration with multiple power transmission antennas 105, with a resonant capacitor 107 and a switch unit 108 provided for each power transmission antenna. In FIG. 3, the control unit 101, power supply unit 102, power transmission unit 103, communication unit 104, and memory 106 are shown as separate entities, but any number of functional block elements may be implemented within the same chip.
　制御部１０１は、例えばメモリ１０６に記憶されている制御プログラムを実行することにより、ＴＸ全体を制御する。また、制御部１０１は、ＴＸにおける機器認証のための通信を含む、送電に関わる制御を行う。さらに、制御部１０１は、無線電力伝送以外のアプリケーションを実行するための制御を行うことができる。 The control unit 101 controls the entire TX, for example, by executing a control program stored in the memory 106. The control unit 101 also performs control related to power transmission, including communication for device authentication in the TX. Furthermore, the control unit 101 can perform control for executing applications other than wireless power transmission.
　制御部１０１は、ＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）またはＭＰＵ（ＭｉｃｒｏＰｒｏｃｅｓｓｏｒ　Ｕｎｉｔ）等の１つ以上のプロセッサーを含んで構成される。あるいは、制御部１０１は、特定用途向け集積回路（ＡＳＩＣ：Ａｐｐｌｉｃａｔｉｏｎ　Ｓｐｅｃｉｆｉｃ　Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ）等のハードウェアで構成されてもよい。 The control unit 101 includes one or more processors, such as a CPU (Central Processing Unit) or an MPU (Microprocessor Unit). Alternatively, the control unit 101 may be configured with hardware, such as an application specific integrated circuit (ASIC).
　また、制御部１０１は、所定の処理を実行するようにコンパイルされたＦＰＧＡ（Ｆｉｅｌｄ　Ｐｒｏｇｒａｍｍａｂｌｅ　Ｇａｔｅ　Ａｒｒａｙ）等のアレイ回路を含んで構成されてもよい。制御部１０１は、各種処理の実行中に記憶しておくべき情報をメモリ１０６に記憶させる処理や、タイマ（不図示）を用いた計時処理を実行することができる。 The control unit 101 may also be configured to include an array circuit such as an FPGA (Field Programmable Gate Array) compiled to execute a specified process. The control unit 101 can execute a process of storing information to be stored in the memory 106 during execution of various processes, and a time measurement process using a timer (not shown).
　電源部１０２は、各機能ブロック要素への電源供給を行う。電源部１０２は、例えば、商用電源への電源接続回路やバッテリを備える。バッテリは商用電源から供給される電力により蓄電される。 The power supply unit 102 supplies power to each functional block element. The power supply unit 102 includes, for example, a power supply connection circuit to a commercial power source and a battery. The battery is charged with power supplied from the commercial power source.
　送電部１０３は、電源部１０２から入力される直流電力または交流電力を、無線電力伝送に用いる周波数帯域の交流電力に変換し、交流電力を送電アンテナ１０５へ入力することによって、ＲＸに受電させるための電磁波を発生させる。 The power transmission unit 103 converts the DC or AC power input from the power supply unit 102 into AC power in the frequency band used for wireless power transmission, and inputs the AC power to the power transmission antenna 105, thereby generating electromagnetic waves for the RX to receive power.
　例えば、送電部１０３はインバータを備え、電源部１０２が供給する直流電圧を、ハーフブリッジ構成またはフルブリッジ構成のスイッチング回路で交流電圧に変換する。送電部１０３はブリッジを構成する複数のＦＥＴ（Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｅｒ）と、複数のＦＥＴのＯＮ／ＯＦＦを制御するゲートドライバを含む。 For example, the power transmission unit 103 includes an inverter and converts the DC voltage supplied by the power supply unit 102 into an AC voltage using a switching circuit with a half-bridge or full-bridge configuration. The power transmission unit 103 includes multiple FETs (Field Effect Transistors) that form a bridge, and a gate driver that controls the ON/OFF of the multiple FETs.
　送電部１０３は、送電アンテナ１０５に入力する電圧（送電電圧）もしくは電流（送電電流）、またはその両方を調節することにより、出力させる電磁波の強度を制御する。送電電圧または送電電流の大小により電磁波の強弱が制御される。 The power transmitting unit 103 controls the intensity of the electromagnetic waves to be output by adjusting the voltage (power transmission voltage) or current (power transmission current), or both, input to the power transmitting antenna 105. The strength of the electromagnetic waves is controlled by the magnitude of the power transmission voltage or power transmission current.
　送電部１０３では、制御部１０１からの指示信号に基づいて、送電アンテナ１０５による送電の開始もしくは停止、または出力させる電磁波の強度が制御されるように、交流周波数の電力に係る出力制御が行われる。また、送電部１０３はＷＰＣ規格に対応した受電装置４０１の充電部（図４：２０６）に１５ワット（Ｗ）の電力を出力するだけの電力供給能力があるものとする。 In the power transmission unit 103, output control of AC frequency power is performed so that the power transmission by the power transmission antenna 105 is started or stopped, or the intensity of the electromagnetic waves to be output is controlled based on an instruction signal from the control unit 101. In addition, the power transmission unit 103 has a power supply capacity of outputting 15 watts (W) of power to the charging unit (206 in FIG. 4) of the power receiving device 401 that complies with the WPC standard.
　通信部１０４は制御部１０１と送電部１０３に接続され、ＲＸとの間でＷＰＣ規格に基づく送電制御のための通信を行う。通信部１０４は、送電アンテナ１０５から出力される電磁波の周波数偏移変調を行い、ＲＸへ情報を伝送して通信を行う。また、通信部１０４は、ＲＸが振幅変調または負荷変調した送電アンテナ１０５から送電される電磁波を復調して、ＲＸが送信した情報を取得する。 The communication unit 104 is connected to the control unit 101 and the power transmitting unit 103, and performs communication with the RX for power transmission control based on the WPC standard. The communication unit 104 performs frequency shift keying of the electromagnetic waves output from the power transmitting antenna 105, and transmits information to the RX to perform communication. The communication unit 104 also demodulates the electromagnetic waves transmitted from the power transmitting antenna 105 that have been amplitude modulated or load modulated by the RX, and acquires the information transmitted by the RX.
　すなわち、通信部１０４による通信は、送電アンテナ１０５から送電される電磁波に通信用の信号が重畳されることにより行われる。あるいは通信部１０４は、送電アンテナ１０５とは異なるアンテナを用いて、ＷＰＣ規格とは異なる規格にしたがってＲＸと通信を行ってもよい。 In other words, communication by the communication unit 104 is performed by superimposing a communication signal on the electromagnetic waves transmitted from the power transmitting antenna 105. Alternatively, the communication unit 104 may use an antenna other than the power transmitting antenna 105 and communicate with the RX in accordance with a standard other than the WPC standard.
　あるいは、ＴＸは複数の通信規格を選択的に用いてＲＸと通信を行ってもよい。この通信規格の例としては、Ｂｌｕｅｔｏｏｔｈ（登録商標）　Ｌｏｗ　Ｅｎｅｒｇｙ（ＢＬＥ）、ＮＦＣ（Ｎｅａｒ　Ｆｉｅｌｄ　Ｃｏｍｍｕｎｉｃａｔｉｏｎ）が挙げられる。 Alternatively, the TX may selectively use multiple communication standards to communicate with the RX. Examples of such communication standards include Bluetooth (registered trademark) Low Energy (BLE) and NFC (Near Field Communication).
　メモリ１０６は、制御プログラムの他に、ＴＸおよびＲＸの状態に関する情報を記憶することができる。ＴＸおよびＲＸの状態に関する情報とは送電電力値、受電電力値等である。ＴＸの状態に関する情報は制御部１０１により取得される。ＲＸの状態に関する情報はＲＸの制御部（図４：２０１）により取得され、通信部１０４が受信可能である。 In addition to the control program, the memory 106 can store information relating to the TX and RX states. Information relating to the TX and RX states includes the transmitted power value, the received power value, etc. Information relating to the TX state is acquired by the control unit 101. Information relating to the RX state is acquired by the RX control unit (201 in Figure 4) and can be received by the communication unit 104.
　送電アンテナ１０５、共振コンデンサ１０７、スイッチ部１０８を含む各ユニットは同一の構成であるため、それらの１つのみ説明する。スイッチ部１０８は、共振コンデンサ１０７および送電アンテナ１０５の直列回路に対して並列に接続されている。制御部１０１は、スイッチ部１０８に制御信号を送信して、そのＯＮ／ＯＦＦ制御を行う。送電アンテナ１０５は、共振コンデンサ１０７と接続されている。 Since each unit including the power transmitting antenna 105, resonant capacitor 107, and switch section 108 has the same configuration, only one of them will be explained. The switch section 108 is connected in parallel to the series circuit of the resonant capacitor 107 and the power transmitting antenna 105. The control section 101 transmits a control signal to the switch section 108 to control its ON/OFF. The power transmitting antenna 105 is connected to the resonant capacitor 107.
　制御部１０１からの制御信号によりスイッチ部１０８がＯＮ状態になって短絡される場合、送電アンテナ１０５と共振コンデンサ１０７は直列共振回路を形成し、特定の周波数ｆ１で共振する。このとき、送電アンテナ１０５と共振コンデンサ１０７、スイッチ部１０８が形成する閉回路に電流が流れる。一方、制御部１０１からの制御信号によってスイッチ部１０８はＯＦＦ状態になり、当該回路が開放されると、送電アンテナ１０５と共振コンデンサ１０７には送電部１０３から電力が供給される。 When the switch unit 108 is turned ON and short-circuited by a control signal from the control unit 101, the power transmitting antenna 105 and resonant capacitor 107 form a series resonant circuit and resonate at a specific frequency f1. At this time, current flows through the closed circuit formed by the power transmitting antenna 105, resonant capacitor 107, and switch unit 108. On the other hand, when the switch unit 108 is turned OFF by a control signal from the control unit 101 and the circuit is opened, power is supplied from the power transmitting unit 103 to the power transmitting antenna 105 and resonant capacitor 107.
　本実施形態の送電装置は、送電アンテナ（送電コイル）１０５、共振コンデンサ１０７、スイッチ部１０８の組を単位とする、送電アンテナ群が実装された構成である。複数の送電アンテナにより、複数の受電装置に対して同時に送電が可能である。また、複数の送電アンテナを用いて単一の受電装置に送電することも可能である。 The power transmission device of this embodiment is configured with a group of power transmission antennas, each of which is a set of a power transmission antenna (power transmission coil) 105, a resonant capacitor 107, and a switch section 108. Power can be transmitted to multiple power receiving devices simultaneously using multiple power transmission antennas. It is also possible to transmit power to a single power receiving device using multiple power transmission antennas.
　図３の例では、制御部１０１からの１つの制御ポートが全てのスイッチ部１０８につながっている。これにより全てのスイッチ部１０８を同時に制御することが可能である。また、個別にスイッチ部１０８を制御することも可能である。例えば、スイッチ部１０８にはそれぞれ固有のアドレスが割り当てられる。 In the example of FIG. 3, one control port from the control unit 101 is connected to all switch units 108. This makes it possible to control all switch units 108 simultaneously. It is also possible to control the switch units 108 individually. For example, each switch unit 108 is assigned a unique address.
　制御部１０１は制御信号の送信先を指定し、所望のスイッチ部１０８を制御することが可能である。また制御部１０１が複数のスイッチ部１０８を個別に制御できるように、複数の制御ポートを設ける構成がある。 The control unit 101 can specify the destination of the control signal and control the desired switch unit 108. In addition, there is a configuration in which multiple control ports are provided so that the control unit 101 can control multiple switch units 108 individually.
　図３ではＴＸが単一の送電部１０３を備える構成であるが、複数の送電部１０３を有する構成がある。複数の送電部１０３のうちの少なくとも１つは、１つまたは複数の送電アンテナに接続され、当該送電アンテナから送電することができる。いずれの構成でも制御部１０１は送電コイルグループによる送電制御を行うことができる。 In FIG. 3, the TX is configured to have a single power transmission unit 103, but there are also configurations with multiple power transmission units 103. At least one of the multiple power transmission units 103 is connected to one or multiple power transmission antennas and can transmit power from the corresponding power transmission antennas. In either configuration, the control unit 101 can control power transmission by the power transmission coil group.
　図４は、受電装置４０１（ＲＸ）の構成例を示すブロック図である。ＲＸは、制御部２０１、ＵＩ（ユーザインタフェース）部２０２、受電部２０３、通信部２０４、受電アンテナ２０５、充電部２０６、バッテリ２０７、メモリ２０８を有する。ＲＸはさらに第１スイッチ部２０９、第２スイッチ部２１０、共振コンデンサ２１１を有する。本実施形態では図４の機能ブロック要素を個別の要素とする例を示すが、複数の機能ブロック要素を１つのハードウェアモジュールとして実現してもよい。 FIG. 4 is a block diagram showing an example of the configuration of a power receiving device 401 (RX). The RX has a control unit 201, a UI (user interface) unit 202, a power receiving unit 203, a communication unit 204, a power receiving antenna 205, a charging unit 206, a battery 207, and a memory 208. The RX further has a first switch unit 209, a second switch unit 210, and a resonant capacitor 211. In this embodiment, an example is shown in which the functional block elements in FIG. 4 are individual elements, but multiple functional block elements may be realized as a single hardware module.
　制御部２０１は、メモリ２０８に記憶されている制御プログラムを実行することによりＲＸの各機能ブロック要素を制御する。制御部２０１は、無線電力伝送以外のアプリケーションを実行するための制御を行うことができる。制御部２０１はＣＰＵまたはＭＰＵ等の１つ以上のプロセッサーを含んで構成される。 The control unit 201 controls each functional block element of the RX by executing a control program stored in the memory 208. The control unit 201 can perform control to execute applications other than wireless power transmission. The control unit 201 includes one or more processors such as a CPU or MPU.
　また、制御部２０１が実行しているＯＳ（Ｏｐｅｒａｔｉｎｇ　Ｓｙｓｔｅｍ）との協働によりＲＸ全体（例えばスマートフォン全体）を制御することができる。あるいは、制御部２０１は、ＡＳＩＣ等のハードウェアで構成されるか、または所定の処理を実行するようにコンパイルされたＦＰＧＡ等のアレイ回路を含んで構成される。制御部２０１は、各種処理の実行中に記憶しておくべき情報をメモリ２０８に記憶させ、また、タイマ（不図示）を用いた計時処理の実行が可能である。 Furthermore, the control unit 201 can control the entire RX (e.g., the entire smartphone) in cooperation with the OS (Operating System) being executed. Alternatively, the control unit 201 is configured with hardware such as an ASIC, or includes an array circuit such as an FPGA compiled to execute a specified process. The control unit 201 stores information to be stored during the execution of various processes in the memory 208, and is also capable of executing timing processes using a timer (not shown).
　ＵＩ部２０２は制御部２０１と接続され、ユーザに対する各種の出力を行う。各種の出力とは、画面表示、ＬＥＤ（Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）の点滅や色の変化、スピーカーによる音声出力、ＲＸ本体の振動等の動作である。ＵＩ部２０２は液晶パネル、スピーカー、バイブレーションモータ等により実現される。 The UI unit 202 is connected to the control unit 201 and performs various outputs to the user. The various outputs include screen display, blinking or color changes of LEDs (Light Emitting Diodes), audio output from a speaker, vibration of the RX main unit, and other operations. The UI unit 202 is realized by an LCD panel, a speaker, a vibration motor, etc.
　受電部２０３は、受電アンテナ２０５を介して、ＴＸの送電アンテナ１０５から放射された電磁波に基づく電磁誘導により生じた交流電力（交流電圧および交流電流）を受電する。そして、受電部２０３は、交流電力を直流または所定周波数の交流電力に変換して充電部２０６に電力を供給する。充電部２０６はバッテリ２０７の充電を行う。 The power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction based on electromagnetic waves radiated from the TX power transmitting antenna 105 via the power receiving antenna 205. The power receiving unit 203 then converts the AC power into DC or AC power of a specific frequency and supplies the power to the charging unit 206. The charging unit 206 charges the battery 207.
　受電部２０３は、ＲＸにおける負荷に対して電力の供給に必要な整流部（整流器、整流回路）および電圧制御部を含む。整流部は、受電アンテナ２０５を介して受電した、送電アンテナからの交流電圧および交流電流を直流電圧および直流電流に変換する。電圧制御部は、整流部から入力される直流電圧のレベルを所定レベルに変換する。 The power receiving unit 203 includes a rectifier unit (rectifier, rectifier circuit) and a voltage control unit required for supplying power to the load in RX. The rectifier unit converts the AC voltage and AC current received from the power transmitting antenna via the power receiving antenna 205 into DC voltage and DC current. The voltage control unit converts the level of the DC voltage input from the rectifier unit to a predetermined level.
　所定レベルとは、制御部２０１および充電部２０６等の動作が可能な直流電圧のレベルである。上述のＧＰは、受電部２０３から出力されることが保証される電力量である。受電部２０３は、充電部２０６からバッテリ２０７への充電用の電力を供給する。受電部２０３は充電部２０６に１５ワットの電力を出力するだけの電力供給能力があるものとする。 The specified level is a DC voltage level at which the control unit 201, charging unit 206, etc. can operate. The above-mentioned GP is the amount of power guaranteed to be output from the power receiving unit 203. The power receiving unit 203 supplies power for charging the battery 207 from the charging unit 206. It is assumed that the power receiving unit 203 has a power supply capacity sufficient to output 15 watts of power to the charging unit 206.
　通信部２０４は、ＴＸが有する通信部１０４との間で、ＷＰＣ規格に基づく受電制御のための通信を行う。通信部２０４は受電アンテナ２０５と制御部２０１に接続されている。通信部２０４は、受電アンテナ２０５から入力された電磁波を復調してＴＸから送信された情報を取得する。 The communication unit 204 communicates with the communication unit 104 of the TX for power reception control based on the WPC standard. The communication unit 204 is connected to the power receiving antenna 205 and the control unit 201. The communication unit 204 demodulates the electromagnetic waves input from the power receiving antenna 205 to obtain the information transmitted from the TX.
　通信部２０４は、入力された電磁波の負荷変調または振幅変調を行って、ＴＸへ送信すべき情報に関する信号を電磁波に重畳することにより、ＴＸとの間で通信を行う。なお、通信部２０４は、受電アンテナ２０５とは異なるアンテナを用いたＷＰＣ規格とは異なる規格にしたがってＴＸとの通信を行ってもよい。あるいは通信部２０４は、上記複数の通信規格を選択的に用いてＴＸとの通信を行ってもよい。 The communication unit 204 performs load modulation or amplitude modulation of the input electromagnetic waves and superimposes a signal related to information to be transmitted to the TX onto the electromagnetic waves, thereby communicating with the TX. Note that the communication unit 204 may communicate with the TX according to a standard other than the WPC standard using an antenna other than the receiving antenna 205. Alternatively, the communication unit 204 may selectively use the above-mentioned multiple communication standards to communicate with the TX.
　メモリ２０８は、制御プログラムの他に、ＴＸおよびＲＸの状態に関する情報等を記憶する。ＲＸの状態に関する情報は制御部２０１により取得される。またＴＸの状態に関する情報はＴＸの制御部１０１により取得され、通信部２０４により受信することができる。 In addition to the control program, the memory 208 stores information about the status of the TX and RX. Information about the status of the RX is acquired by the control unit 201. Information about the status of the TX is acquired by the control unit 101 of the TX, and can be received by the communication unit 204.
　第１スイッチ部２０９および第２スイッチ部２１０は、制御部２０１により制御される。第１スイッチ部２０９は充電部２０６とバッテリ２０７との間に設けられている。第１スイッチ部２０９は、受電部２０３が受電した電力をバッテリ２０７に供給するか否かを制御する機能と、負荷量を制御する機能を有する。 The first switch unit 209 and the second switch unit 210 are controlled by the control unit 201. The first switch unit 209 is provided between the charging unit 206 and the battery 207. The first switch unit 209 has a function of controlling whether or not the power received by the power receiving unit 203 is to be supplied to the battery 207, and a function of controlling the load amount.
　制御部２０１によって第１スイッチ部２０９がＯＦＦ状態となって開放される場合、受電部２０３が受電した電力はバッテリ２０７に供給されない。制御部２０１により第１スイッチ部２０９がＯＮ状態となって短絡される場合、受電部２０３が受電した電力はバッテリ２０７に供給される。 When the control unit 201 turns the first switch unit 209 to the OFF state and opens it, the power received by the power receiving unit 203 is not supplied to the battery 207. When the control unit 201 turns the first switch unit 209 to the ON state and shorts it, the power received by the power receiving unit 203 is supplied to the battery 207.
　図４の例では第１スイッチ部２０９が充電部２０６とバッテリ２０７との間に配置されているが、第１スイッチ部２０９は受電部２０３と充電部２０６との間に配置されてもよい。あるいは第１スイッチ部２０９は、受電アンテナ２０５と共振コンデンサ２１１、および第２スイッチ部２１０が形成する閉回路と、受電部２０３との間に配置されてもよい。 In the example of FIG. 4, the first switch unit 209 is disposed between the charging unit 206 and the battery 207, but the first switch unit 209 may be disposed between the power receiving unit 203 and the charging unit 206. Alternatively, the first switch unit 209 may be disposed between the power receiving unit 203 and the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210.
　この場合、第１スイッチ部２０９は、受電アンテナ２０５が受電した電力を受電部２０３に供給するか否かを制御する機能を有する。また、図４の例では第１スイッチ部２０９が１つの機能ブロック要素として記載されているが、第１スイッチ部２０９を充電部２０６または受電部２０３の一部として実現することが可能である。 In this case, the first switch unit 209 has a function of controlling whether or not the power received by the power receiving antenna 205 is supplied to the power receiving unit 203. Also, in the example of FIG. 4, the first switch unit 209 is described as one functional block element, but it is possible to realize the first switch unit 209 as part of the charging unit 206 or the power receiving unit 203.
　受電部２０３の入力側にて第２スイッチ部２１０は共振コンデンサ２１１と並列に接続されている。受電アンテナ２０５は共振コンデンサ２１１と接続されており、第２スイッチ部２１０がＯＮ状態になって短絡される場合、受電アンテナ２０５と共振コンデンサ２１１は直列共振回路を形成し、特定の周波数ｆ２で共振する。 On the input side of the power receiving unit 203, the second switch unit 210 is connected in parallel with the resonant capacitor 211. The power receiving antenna 205 is connected to the resonant capacitor 211, and when the second switch unit 210 is turned on and short-circuited, the power receiving antenna 205 and the resonant capacitor 211 form a series resonant circuit and resonate at a specific frequency f2.
　この時、受電アンテナ２０５と共振コンデンサ２１１、第２スイッチ部２１０が形成する閉回路に電流が流れ、受電部２０３に電流は流れない。一方、第２スイッチ部２１０がＯＦＦ状態になって開放される場合、受電アンテナ２０５と共振コンデンサ２１１により受電された電力は、受電部２０３へ供給される。 At this time, current flows through the closed circuit formed by the power receiving antenna 205, resonant capacitor 211, and second switch section 210, and no current flows through the power receiving section 203. On the other hand, when the second switch section 210 is turned OFF and opened, the power received by the power receiving antenna 205 and resonant capacitor 211 is supplied to the power receiving section 203.
　次に、図５を参照して、ＴＸの制御部１０１の機能について説明する。図５は、送電装置４０２（ＴＸ）の制御部１０１の機能構成例を示すブロック図である。制御部１０１は、通信制御部３０１、送電制御部３０２、測定部３０３、設定部３０４、異物検出部３０５を有する。通信制御部３０１は、通信部１０４を介してＷＰＣ規格に基づいたＲＸとの通信制御を行う。 Next, the function of the control unit 101 of the TX will be described with reference to FIG. 5. FIG. 5 is a block diagram showing an example of the functional configuration of the control unit 101 of the power transmitting device 402 (TX). The control unit 101 has a communication control unit 301, a power transmission control unit 302, a measurement unit 303, a setting unit 304, and a foreign object detection unit 305. The communication control unit 301 controls communication with the RX based on the WPC standard via the communication unit 104.
　送電制御部３０２は、送電部１０３を制御することで、ＲＸへの送電を制御する。測定部３０３は、後述する波形減衰指標を測定する。また測定部３０３は、送電部１０３を介してＲＸに対して送電する電力を計測し、単位時間ごとに平均送電電力を測定する。また測定部３０３は、送電アンテナ１０５のＱ値を測定する。 The power transmission control unit 302 controls the power transmission unit 103 to control the power transmission to the RX. The measurement unit 303 measures a waveform attenuation index, which will be described later. The measurement unit 303 also measures the power transmitted to the RX via the power transmission unit 103, and measures the average transmitted power per unit time. The measurement unit 303 also measures the Q value of the power transmission antenna 105.
　設定部３０４は、測定部３０３により測定された波形減衰指標に基づいて、異物検出に用いる閾値を算出して設定する。異物検出部３０５は、Ｐｏｗｅｒ　Ｌｏｓｓ法、Ｑ値計測法、波形減衰法による異物検出処理を実行する。また異物検出部３０５は、その他の方法を用いて異物検出処理を実行してもよい。 The setting unit 304 calculates and sets a threshold value used for foreign object detection based on the waveform attenuation index measured by the measurement unit 303. The foreign object detection unit 305 executes foreign object detection processing using the power loss method, the Q value measurement method, and the waveform attenuation method. The foreign object detection unit 305 may also execute foreign object detection processing using other methods.
　例えばＮＦＣ（Ｎｅａｒ　Ｆｅａｌｄ　Ｃｏｍｍｕｎｉｃａｔｉｏｎ）通信機能を備えるＴＸにて、異物検出部３０５は、ＮＦＣ規格による対向機検出機能を用いて異物検出処理を行うことができる。また異物検出部３０５は、異物検出機能以外に、ＴＸ上の状態が変化したことを検出可能である。例えば、ＴＸは、ＴＸ上の受電装置４０１の数の増減を検出可能である。 For example, in a TX equipped with an NFC (Near Field Communication) communication function, the foreign object detection unit 305 can perform foreign object detection processing using the opposing device detection function according to the NFC standard. In addition to the foreign object detection function, the foreign object detection unit 305 can also detect changes in the state of the TX. For example, the TX can detect an increase or decrease in the number of power receiving devices 401 on the TX.
　設定部３０４は、Ｐｏｗｅｒ　Ｌｏｓｓ法、Ｑ値計測法、波形減衰法による異物検出に必要な、異物の有無の判定基準となる閾値を設定する。また設定部３０４は、その他の方法を用いた異物検出処理に必要な、異物の有無の判定基準となる閾値を設定することができる。設定部３０４により設定された閾値を用いて異物検出部３０５は、測定部３０３により測定された波形減衰指標、送電電力、Ｑ値に基づく異物検出処理を実行することができる。 The setting unit 304 sets a threshold value that is a criterion for determining whether or not a foreign object is present, which is necessary for foreign object detection using the power loss method, the Q-value measurement method, and the waveform attenuation method. The setting unit 304 can also set a threshold value that is a criterion for determining whether or not a foreign object is present, which is necessary for foreign object detection processing using other methods. Using the threshold value set by the setting unit 304, the foreign object detection unit 305 can execute foreign object detection processing based on the waveform attenuation index, transmission power, and Q-value measured by the measurement unit 303.
　通信制御部３０１、送電制御部３０２、測定部３０３、設定部３０４、異物検出部３０５が実行する処理については、制御部１０１の備えるＣＰＵ等が実行するプログラムを用いて実現可能である。各処理は、それぞれが独立したプログラムにしたがい、イベント処理等によりプログラム間の同期をとりながら並行して実行される。ただし、これらの処理のうち、２つ以上が１つのプログラムによる処理に組み込まれていてもよい。 The processes performed by the communication control unit 301, power transmission control unit 302, measurement unit 303, setting unit 304, and foreign object detection unit 305 can be realized using programs executed by a CPU or the like provided in the control unit 101. Each process is executed in parallel according to an independent program, with the programs synchronized by event processing or the like. However, two or more of these processes may be incorporated into the processing of a single program.
　次に、ＷＰＣ規格に従った電力伝送のための処理の流れを説明する。ＷＰＣ規格では、Ｓｅｌｅｃｔｉｏｎ　Ｐｈａｓｅ、Ｐｉｎｇ　Ｐｈａｓｅ、Ｉ＆Ｃ　Ｐｈａｓｅ、Ｎｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅ、Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅ、およびＰｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅが規定されている。以下では、これらのＰｈａｓｅにおけるＴＸおよびＲＸの動作について、図６を用いて説明する。 Next, the process flow for power transmission according to the WPC standard will be explained. The WPC standard specifies the Selection Phase, Ping Phase, I&C Phase, Negotiation Phase, Calibration Phase, and Power Transfer Phase. The operation of the TX and RX in these phases will be explained below with reference to Figure 6.
　図６は、ＷＰＣ規格に従った電力伝送の例を説明するシーケンス図である。左側に送電装置４０２（ＴＸ）の動作を示し、右側に受電装置４０１（ＲＸ）の動作を示す。Ｆ５０１でＴＸは、送電可能範囲内に存在する物体を検出するために、ＷＰＣ規格のＡＰを繰り返し間欠送信している。 FIG. 6 is a sequence diagram explaining an example of power transmission according to the WPC standard. The left side shows the operation of the power transmitting device 402 (TX), and the right side shows the operation of the power receiving device 401 (RX). At F501, the TX repeatedly and intermittently transmits a WPC standard AP to detect an object present within the power transmission range.
　ＴＸはＳｅｌｅｃｔｉｏｎ　ＰｈａｓｅとＰｉｎｇ　Ｐｈａｓｅとして規定されている処理を実行し、ＲＸが載置されるのを待ち受ける。Ｆ５０２でＲＸのユーザは、ＲＸ（例えばスマートフォン）を充電するためにＴＸに近づける。例えば、ユーザはＲＸを充電台４０３に載置する。Ｆ５０３でＴＸはＡＰを送信し、Ｆ５０４でＴＸは、送電可能範囲内に物体が存在することを検知する。Ｆ５０５でＴＸは、ＲＸに対して送電可能な複数の送電コイルを選択し、送電コイルグループを構成する。 The TX executes the processes defined as the Selection Phase and Ping Phase, and waits for the RX to be placed on it. At F502, the user of the RX brings the RX (e.g., a smartphone) close to the TX in order to charge it. For example, the user places the RX on the charging stand 403. At F503, the TX transmits an AP, and at F504, the TX detects the presence of an object within the power transmission range. At F505, the TX selects multiple power transmission coils that can transmit power to the RX, and forms a power transmission coil group.
　図７（Ａ）～（Ｃ）は、送電コイルグループを表現した図である。図７（Ａ）は、複数の送電コイルを実装した送電装置４０２（ＴＸ）の構成例を示す。複数の送電コイルが重なり合うように配置されており、ＴＸ上で送電可能な範囲を広く確保できる。図７（Ｂ）は送電コイルグループ１１０１の構成図である。 FIGS. 7(A) to (C) are diagrams showing power transmission coil groups. FIG. 7(A) shows an example of the configuration of a power transmission device 402 (TX) that implements multiple power transmission coils. Multiple power transmission coils are arranged so as to overlap each other, ensuring a wide range over which power can be transmitted on the TX. FIG. 7(B) is a diagram showing the configuration of a power transmission coil group 1101.
　実線で表現された３つの送電コイルが送電コイルグループ１１０１を示している。ＴＸは、制御部１０１、送電部１０３、スイッチ部１０８の制御により、複数の送電コイルをグループ化して同時に送電を行うことが可能である。図７（Ｃ）は受電装置４０１（ＲＸ）が送電コイルグループ１１０１に接近した状態を示している（図６：Ｆ５０２）。 The three power transmission coils represented by solid lines indicate the power transmission coil group 1101. TX can group multiple power transmission coils and transmit power simultaneously through the control of the control unit 101, the power transmission unit 103, and the switch unit 108. Figure 7 (C) shows the state in which the power receiving device 401 (RX) approaches the power transmission coil group 1101 (Figure 6: F502).
　送電コイルグループ１１０１とＲＸとが対応付けられている。図６のＦ５０４でＴＸ上のＲＸの載置が検知されると、Ｆ５０５でＴＸは、送電コイルグループ１１０１と受電装置４０１との対応付けを行う。この関係によりＰｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにおいて、送電コイルグループ１１０１を使用して１つのＲＸへの送電が可能になる。 The power transmission coil group 1101 and the RX are associated with each other. When the placement of the RX on the TX is detected in F504 in FIG. 6, the TX associates the power transmission coil group 1101 with the power receiving device 401 in F505. This relationship makes it possible to transmit power to one RX using the power transmission coil group 1101 in the Power Transfer Phase.
　次に図６のＦ５０６でＴＸは、ＡＰの変化から送電コイルグループ１１０１を構成する各送電コイルのＱ値測定を行う。Ｑ値は後述のＱ値測定法により取得される値であり、送電中の波形減衰法による異物検出における基準のＱ値として使用される。 Next, in F506 in FIG. 6, the TX measures the Q value of each of the power transmission coils that make up the power transmission coil group 1101 based on the change in AP. The Q value is a value obtained by the Q value measurement method described below, and is used as the reference Q value for foreign object detection using the waveform attenuation method during power transmission.
　Ｆ５０７でＴＸはＷＰＣ規格のＤＰを送信する。Ｆ５０８でＲＸはＤＰを受信すると、ＴＸがＲＸを検知したことを把握できる。またＴＸは、ＤＰに対する所定の応答があった場合、検出された物体がＲＸであり、ＲＸが充電台４０３に載置されたと判定する。 In F507, the TX transmits a DP conforming to the WPC standard. When the RX receives the DP in F508, it knows that the TX has detected the RX. Furthermore, if there is a specified response to the DP, the TX determines that the detected object is the RX and that the RX has been placed on the charging stand 403.
　ＴＸは、ＲＸの載置を検出した場合、ＷＰＣ規格で規定されたＩ＆Ｃ　Ｐｈａｓｅでの通信により、Ｆ５０９でＲＸから識別情報と能力情報を取得する。ＲＸの識別情報は、Ｍａｎｕｆａｃｔｕｒｅｒ　ＣｏｄｅとＢａｓｉｃ　Ｄｅｖｉｃｅ　ＩＤを含む。ＲＸの能力情報は、例えば下記の情報を含む。 When the TX detects that the RX has been placed, it obtains identification and capability information from the RX at F509 through communication in the I&C Phase defined in the WPC standard. The RX identification information includes the Manufacturer Code and Basic Device ID. The RX capability information includes, for example, the following information:
・対応しているＷＰＣ規格のバージョンを特定することが可能な情報。
・ＲＸが負荷に供給できる最大電力を特定する値であるＭａｘｉｍｕｍ　Ｐｏｗｅｒ　Ｖａｌｕｅ。
・ＷＰＣ規格のＮｅｇｏｔｉａｔｉｏｎ機能を有するかを示す情報。 - Information that can identify the version of the WPC standard that is supported.
- Maximum Power Value, a value that specifies the maximum power the RX can supply to the load.
Information indicating whether or not the device has a WPC standard Negotiation function.
　ＴＸは、ＷＰＣ規格のＩ＆Ｃ　Ｐｈａｓｅでの通信以外の方法でＲＸの識別情報と能力情報を取得してもよい。また、識別情報は、Ｗｉｒｅｌｅｓｓ　Ｐｏｗｅｒ　ＩＤ等の、ＲＸの個体を識別可能な任意の他の識別情報でもよい。能力情報として、上記以外の情報を含んでいてもよい。 The TX may obtain the identification information and capability information of the RX by a method other than communication in the I&C Phase of the WPC standard. The identification information may also be any other identification information capable of identifying an individual RX, such as a Wireless Power ID. The capability information may include information other than the above.
　続いてＦ５１０でＴＸは、ＷＰＣ規格で規定されたＮｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅでの通信により、ＲＸとの間でＧＰ値を決定する。なお、Ｆ５１０では、ＧＰ値を決定するための他の方法やプロトロコルを採用してもよい。 Next, at F510, the TX determines the GP value with the RX through communication in the Negotiation Phase defined in the WPC standard. Note that at F510, other methods or protocols for determining the GP value may be adopted.
　また、ＲＸがＮｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅに対応していないことを示す情報を、ＴＸが、例えばＦ５０９にて取得した場合を想定する。この場合、Ｎｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅでの通信は行われず、ＧＰ値は（例えばＷＰＣ規格で予め規定された）小さな値に決定される。本実施形態では、ＧＰ＝５（ワット）とする。 Also, assume that the TX acquires information, for example, in F509, indicating that the RX does not support the Negotiation Phase. In this case, communication in the Negotiation Phase is not performed, and the GP value is determined to be a small value (predefined in advance, for example, in the WPC standard). In this embodiment, GP = 5 (watts).
　ＴＸは、ＧＰ値の決定後、当該ＧＰ値に基づいてＰｏｗｅｒ　Ｌｏｓｓ法のＣＡＬ処理を行う。まずＦ５１１でＲＸは、所定の状態における受電電力を含む情報（以降、第１の基準受電電力情報と呼ぶ。）をＴＸに送信する。所定の状態とは軽負荷状態であり、例えば負荷切断状態、または送電電力が第１の閾値以下の負荷状態である。 After determining the GP value, the TX performs CAL processing of the Power Loss method based on the GP value. First, in F511, the RX transmits information including the received power in a specified state (hereinafter referred to as first reference received power information) to the TX. The specified state is a light load state, such as a load disconnected state or a load state in which the transmitted power is equal to or less than a first threshold.
　例えば、第１の基準受電電力情報は、ＴＸの送電電力が５００ミリワットの時の、ＲＸの受電電力情報とする。第１の基準受電電力情報は、ＷＰＣ規格で規定されるＲｅｃｅｉｖｅｄ　Ｐｏｗｅｒ　Ｄａｔａ　Ｐａｃｋｅｔ（ｍｏｄｅ１）に含まれる情報である。以下、当該パケットを「ＲＰ１」と表記する。ただし、ＲＰ１に限定されることなく、他のメッセージが用いられてもよい。 For example, the first reference received power information is the received power information of the RX when the transmission power of the TX is 500 milliwatts. The first reference received power information is information contained in the Received Power Data Packet (mode 1) defined in the WPC standard. Hereinafter, this packet will be referred to as "RP1". However, it is not limited to RP1, and other messages may be used.
　ＴＸは、自装置の送電状態に基づいて、第１の基準受電電力情報を受け入れるか否かを判定する。ＴＸは、第１の基準受電電力情報を受け入れる場合、肯定応答であるＡＣＫをＲＸに送信し、第１の基準受電電力情報を受け入れない場合、否定応答であるＮＡＫをＲＸへ送信する。 The TX determines whether or not to accept the first reference received power information based on the power transmission state of its own device. If the TX accepts the first reference received power information, it transmits an ACK, which is a positive response, to the RX. If the TX does not accept the first reference received power information, it transmits an NAK, which is a negative response, to the RX.
　Ｆ５１２でＴＸはＡＣＫをＲＸに送信する。ＲＸは、ＴＸからＡＣＫを受信すると、所定の状態における受電電力を含む情報（以降、第２の基準受電電力情報と呼ぶ。）をＴＸに送信するための処理を行う。所定の状態とは負荷接続状態であり、例えば最大負荷状態、または送電電力が第２の閾値以上の負荷状態である。 At F512, the TX transmits an ACK to the RX. When the RX receives the ACK from the TX, it performs processing to transmit information including the received power in a predetermined state (hereinafter referred to as second reference received power information) to the TX. The predetermined state is a load connection state, such as a maximum load state or a load state in which the transmitted power is equal to or greater than a second threshold value.
　本実施形態では、ＧＰ＝５（ワット）であることから、第２の基準受電電力情報は、ＴＸの送電電力が５ワットの時の、ＲＸの受電電力情報とする。第２の基準受電電力情報は、ＷＰＣ規格で規定されるＲｅｃｅｉｖｅｄ　Ｐｏｗｅｒ　Ｄａｔａ　Ｐａｃｋｅｔ（ｍｏｄｅ２）に含まれる情報である。以下、当該パケットを「ＲＰ２」と表記する。 In this embodiment, since GP = 5 (watts), the second reference received power information is the RX received power information when the TX transmission power is 5 watts. The second reference received power information is information contained in the Received Power Data Packet (mode 2) defined in the WPC standard. Hereinafter, this packet will be referred to as "RP2."
　ただし、ＲＰ２に限定されることなく、他のメッセージが用いられてもよい。Ｆ５１３でＲＸは、送電電力を５ワットまで増加させるために、正値を含む送電出力変更指示をＴＸに送信する。図では正値が（＋）の記号で表現されている。 However, this is not limited to RP2, and other messages may be used. At F513, RX sends a transmission output change instruction including a positive value to TX in order to increase the transmission power to 5 watts. In the figure, the positive value is represented by the (+) symbol.
　Ｆ５１４でＴＸは上記送電出力変更指示を受信し、送電電力を増加させる対応が可能である場合、送電電力を増加させる制御を行い、Ｆ５１５で肯定応答ＡＣＫをＲＸに送信する。Ｆ５１６でＲＸは再び、正値を含む送電出力変更指示をＴＸに送信する。 In F514, the TX receives the transmission output change instruction, and if it is possible to increase the transmission power, it performs control to increase the transmission power and transmits an ACK acknowledgement to the RX in F515. In F516, the RX again transmits a transmission output change instruction including a positive value to the TX.
　第２の基準受電電力情報は、ＴＸの送電電力が５ワットの時の受電電力情報である。ＴＸは、５ワットを超える電力増加要求をＲＸから受信した場合、Ｆ５１７にて、ＲＸの送電出力変更指示に対して否定応答ＮＡＫを送信する。これにより、規定以上の電力の送電が抑制される。 The second reference received power information is the received power information when the transmission power of the TX is 5 watts. When the TX receives a power increase request from the RX that exceeds 5 watts, the TX transmits a negative response NAK to the instruction to change the transmission output of the RX at F517. This prevents the transmission of power above the specified level.
　ＲＸは、ＴＸより否定応答ＮＡＫを受信することで既定の送電電力に到達したと判断する。Ｆ５１８でＲＸは、負荷接続状態における受電電力を含む情報を、第２の基準受電電力情報としてＴＸに送信する。 The RX determines that the default transmission power has been reached by receiving a negative response NAK from the TX. At F518, the RX transmits information including the received power in the load connection state to the TX as second reference received power information.
　ＴＸは、送電電力値と、第１および第２の基準受電電力情報に含まれる受電電力値に基づいて、軽負荷状態と負荷接続状態におけるＴＸとＲＸとの間の電力損失量を算出することができる。また、ＴＸは各状態での電力損失量の間の補間処理を行い、ＴＸの取り得るすべての送電電力におけるＴＸとＲＸとの間の電力損失値を算出することができる。本例では５００ミリワットから５ワットにわたる送電電力範囲にてＴＸとＲＸとの間の電力損失値の算出が可能である。 The TX can calculate the amount of power loss between the TX and RX in a light load state and a load connected state based on the transmission power value and the received power value included in the first and second reference received power information. The TX can also perform an interpolation process between the power loss amounts in each state and calculate the power loss value between the TX and RX for all possible transmission powers of the TX. In this example, it is possible to calculate the power loss value between the TX and RX in a transmission power range from 500 milliwatts to 5 watts.
　Ｆ５１９でＴＸは、ＲＸからの第２の基準受電電力情報に対して肯定応答ＡＣＫを送信し、ＣＡＬ処理を完了する。充電処理を開始可能と判断したＴＸが、ＲＸに対して送電処理を開始した場合、ＲＸの充電が開始される。なお、送電処理の開始前には、Ｆ５２０でＴＸとＲＸは機器認証のための通信処理を行う。 In F519, the TX transmits an ACK acknowledgement to the second reference received power information from the RX, and completes the CAL process. When the TX, which has determined that it is possible to start charging, starts power transmission processing to the RX, charging of the RX starts. Note that before the power transmission processing starts, the TX and RX perform communication processing for device authentication in F520.
　ＴＸとＲＸは、より大きなＧＰに対応可能と判断した場合、Ｆ５２１にてＧＰをより大きな値、例えば１５ワットに再設定することができる。この場合、送電電力を１５ワットまで増加させるためにＦ５２２でＲＸは、正値を含む送電出力変更指示をＴＸに送信する。 If the TX and RX determine that they can support a larger GP, they can reset the GP to a larger value, for example 15 watts, in F521. In this case, the RX sends a transmission output change instruction including a positive value to the TX in F522 to increase the transmission power to 15 watts.
　Ｆ５２３でＴＸは送電出力変更指示に対する肯定応答ＡＣＫを送信する。Ｆ５２４でＲＸは再び、正値を含む送電出力変更指示をＴＸに送信する。Ｆ５２５でＴＸは送電出力変更が不可能であると判断し、否定応答ＮＡＫをＲＸに送信する。 At F523, TX sends an ACK (positive response) to the instruction to change the transmission power output. At F524, RX again sends an instruction to change the transmission power output, including a positive value, to TX. At F525, TX determines that it is not possible to change the transmission power output, and sends a NAK (negative response) to RX.
　ＴＸおよびＲＸは、ＧＰ＝１５（ワット）に対して、再度ＣＡＬ処理を実行する。具体的には、Ｆ５２６でＲＸは、送電電力が１５ワットの時の、ＲＸの負荷接続状態における受電電力を含む情報（以降、第３の基準受電電力情報と呼ぶ。）をＴＸに送信する。ＴＸは、第１、第２、および第３の基準受電電力情報に含まれる受電電力値に基づいてＣＡＬ処理を行う。 The TX and RX perform CAL processing again for GP=15 (watts). Specifically, in F526, the RX transmits information including the received power in the load-connected state of the RX when the transmission power is 15 watts (hereinafter referred to as the third reference received power information) to the TX. The TX performs CAL processing based on the received power values included in the first, second, and third reference received power information.
　この場合、ＴＸの取り得るすべての送電電力である、５００ミリワットから１５ワットにわたる範囲にてＴＸとＲＸとの間の電力損失量を算出することができる。Ｆ５２７でＴＸは、ＲＸからの第３の基準受電電力情報に対して肯定応答ＡＣＫを送信し、ＣＡＬ処理を完了する。 In this case, the amount of power loss between the TX and the RX can be calculated for all possible transmission powers of the TX, ranging from 500 milliwatts to 15 watts. At F527, the TX transmits an ACK acknowledgement to the third reference received power information from the RX, and completes the CAL process.
　Ｆ５２８でＴＸは充電処理を開始可能と判断して、ＲＸに対して送電処理を開始し、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅに移行する。当該フェーズにて、例えばＲＸはＦ５２９で正値を含む送電出力変更要求を行い、Ｆ５３０でＴＸは当該要求に対する否定応答ＮＡＫを送信する。Ｆ５３１でＲＸは負値（図中、（－）の記号で示す）を含む送電出力変更要求を行い、Ｆ５３２でＴＸは当該要求に対する肯定応答ＡＣＫを送信する。 In F528, TX determines that charging can be started, starts power transmission processing to RX, and moves to the Power Transfer Phase. In this phase, for example, RX makes a request to change the transmission output power including a positive value in F529, and TX sends a negative response NAK to the request in F530. In F531, RX makes a request to change the transmission output power including a negative value (indicated by the (-) symbol in the figure), and TX sends a positive response ACK to the request in F532.
　Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅでは、送電中に異物検出が行われる。ＴＸは事前にＣＡＬ処理を行い、送電電力と受電電力との差分から、異物が存在しない状態におけるＴＸとＲＸとの間の電力損失量を算出する。 In the Power Transfer Phase, foreign object detection is performed during power transmission. The TX performs CAL processing in advance and calculates the amount of power loss between the TX and RX in the absence of a foreign object from the difference between the transmitted power and the received power.
　算出された値は、送電中の通常状態（異物がない状態）における、基準の電力損失量に相当する。そしてＴＸは、ＣＡＬ処理後の送電中に測定されるＴＸとＲＸとの間の電力損失量が、基準の電力損失量から閾値以上に変化した場合、「異物あり」または「異物が存在する可能性が高い」と判定する。 The calculated value corresponds to the reference power loss amount during normal power transmission (when there is no foreign object). If the power loss amount between the TX and RX measured during power transmission after CAL processing changes from the reference power loss amount to a threshold value or more, the TX determines that there is a "foreign object" or that there is a "high possibility that a foreign object is present."
　上記Ｐｏｗｅｒ　Ｌｏｓｓ法を用いて、ＴＸからＲＸへの送電中に、電力損失の測定結果に基づいて異物検出が行われる。この異物検出は、ＴＸが大きな電力を送電しているときに異物検出精度が低下するという短所がある一方で、送電を継続しながら異物検出を行えるので、送電効率を高く保つことが可能であるという長所がある。 Using the above-mentioned Power Loss method, foreign object detection is performed based on the results of measuring power loss while transmitting power from the TX to the RX. While this method of foreign object detection has the disadvantage that the accuracy of foreign object detection decreases when the TX is transmitting a large amount of power, it has the advantage that foreign object detection can be performed while continuing to transmit power, making it possible to maintain high power transmission efficiency.
　ところで、Ｐｏｗｅｒ　Ｌｏｓｓ法による異物検出のみでは、異物の誤検出の可能性や、異物が存在するにも関わらず「異物無し」と誤判定される可能性がある。例えば、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　ＰｈａｓｅにてＴＸとＲＸの近傍に異物が存在すると、異物からの発熱等が大きくなる可能性がある。そこで本実施形態では、異物検出精度を向上させるために、Ｐｏｗｅｒ　Ｌｏｓｓ法とは異なる異物検出方法が実施される。 However, when detecting foreign objects using only the Power Loss method, there is a possibility of false detection of foreign objects, or a false determination that there is no foreign object even though there is a foreign object. For example, if a foreign object is present near TX and RX in the Power Transfer Phase, there is a possibility that heat generation from the foreign object will increase. Therefore, in this embodiment, a foreign object detection method other than the Power Loss method is implemented to improve the accuracy of foreign object detection.
　次に、波形減衰法による異物検出方法を説明する。Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅでの送電波形（電圧波形または電流波形）を用いて異物検出を行うことにより、新たに規定される異物検出用信号等を用いることなく、異物検出が可能となる。波形減衰法は、送電波形の減衰状態に基づいて異物検出を行う方法であり、図８を用いて説明する。 Next, a method for detecting foreign objects using the waveform attenuation method will be explained. By detecting foreign objects using the transmitted power waveform (voltage waveform or current waveform) in the Power Transfer Phase, foreign objects can be detected without using a newly defined foreign object detection signal, etc. The waveform attenuation method is a method for detecting foreign objects based on the attenuation state of the transmitted power waveform, and will be explained using Figure 8.
　図８は、波形減衰法による異物検出の原理を説明する図である。ＴＸからＲＸへの送電に係る送電波形を用いた異物検出の例を示す。図８にて横軸は時間軸であり、縦軸は電圧値または電流値を表す。波形６００は、例えばＴＸの送電アンテナ１０５に印加される高周波電圧値（以下、単に電圧値という）の時間経過に伴う変化を示している。 FIG. 8 is a diagram explaining the principle of foreign object detection using the waveform attenuation method. An example of foreign object detection using a power transmission waveform related to power transmission from TX to RX is shown. In FIG. 8, the horizontal axis is the time axis, and the vertical axis represents the voltage value or current value. Waveform 600 shows, for example, the change over time in the high-frequency voltage value (hereinafter simply referred to as the voltage value) applied to the power transmission antenna 105 of the TX.
　送電アンテナ１０５を介してＲＸに送電を行っているＴＸは、時刻Ｔ０において送電を停止する。例えば時刻Ｔ０では、電源部１０２からの送電用の電力供給が停止される。送電波形の周波数は、例えばＷＰＣ規格で使用される８５ｋＨｚから２０５ｋＨｚまでの間にある、固定された周波数である。 The TX, which is transmitting power to the RX via the power transmitting antenna 105, stops transmitting power at time T0 . For example, at time T0 , the power supply for power transmission from the power supply unit 102 is stopped. The frequency of the transmitting radio wave is a fixed frequency, for example, between 85 kHz and 205 kHz used in the WPC standard.
　波形６００上の点６０１は、高周波電圧の包絡線上の点であり、（Ｔ１，Ａ１）は、時刻Ｔ１における電圧値がＡ１であることを示す。波形６００上の点６０２は、高周波電圧の包絡線上の点であり、（Ｔ２、Ａ２）は、時刻Ｔ２における電圧値がＡ２であることを示す。 A point 601 on the waveform 600 is a point on the envelope of the high frequency voltage, and ( T1 , A1 ) indicates that the voltage value at time T1 is A1 . A point 602 on the waveform 600 is a point on the envelope of the high frequency voltage, and ( T2 , A2 ) indicates that the voltage value at time T2 is A2 .
　送電アンテナ１０５の品質係数を表すＱ値（Ｑファクター）は、時刻Ｔ０以降の電圧値の時間変化に基づいて求めることが可能である。例えば、高周波電圧の包絡線上の点６０１および６０２における時刻、電圧値、および時刻Ｔ０にて送電を停止した直後の高周波電圧の周波数ｆに基づいて、ＴＸは式１によりＱ値を算出する。尚、式１中、ｌｎは自然対数関数を表す。
　Ｑ＝π・ｆ・（Ｔ２－Ｔ１）／ｌｎ（Ａ１／Ａ２）　（式１） The Q factor, which represents the quality factor of the power transmitting antenna 105, can be calculated based on the change over time in the voltage value after time T0 . For example, the TX calculates the Q factor using Equation 1 based on the time and voltage value at points 601 and 602 on the envelope of the high frequency voltage, and the frequency f of the high frequency voltage immediately after power transmission is stopped at time T0 . In Equation 1, ln represents a natural logarithm function.
Q = π f (T 2 - T 1 ) / ln (A 1 / A 2 ) (Equation 1)
　Ｑ値は、ＴＸとＲＸの近傍に異物が存在する場合に低下するが、その理由は異物によってエネルギー損失が発生するからである。よって、電圧値の減衰の傾きに着目すると、異物が存在しない場合よりも、異物が存在する場合の方が、点６０１と点６０２を結ぶ直線の傾きは大きくなる。異物によるエネルギー損失が発生する場合、波形６００の振幅の減衰率が高くなる。 The Q value decreases when a foreign object is present near TX and RX, because the foreign object causes energy loss. Therefore, when looking at the slope of the attenuation of the voltage value, the slope of the line connecting points 601 and 602 is greater when a foreign object is present than when no foreign object is present. When energy loss occurs due to a foreign object, the attenuation rate of the amplitude of waveform 600 increases.
　波形減衰法では、点６０１と点６０２との間の電圧値の減衰状態に基づいて異物の有無の判定を行うことができる。実際に異物の有無を判定する上では、減衰状態を表す何らかの数値の比較によって判定をすることが可能となる。例えば、Ｑ値を用いて判定を行う場合、Ｑ値が基準値よりも低くなることは、波形減衰率（単位時間当たりの波形の振幅の減少度合い）が高くなることを意味する。 In the waveform attenuation method, the presence or absence of a foreign object can be determined based on the attenuation state of the voltage value between points 601 and 602. In fact, the presence or absence of a foreign object can be determined by comparing some numerical value that represents the attenuation state. For example, when the determination is made using the Q value, a Q value lower than the reference value means that the waveform attenuation rate (the degree of decrease in the amplitude of the waveform per unit time) is high.
　別例として、（Ａ１－Ａ２）／（Ｔ２－Ｔ１）により算出される、点６０１と点６０２を結ぶ直線の傾きを用いて判定を行う方法がある。また、電圧値の減衰状態を測定する時刻（Ｔ１およびＴ２）が固定であるとした場合、電圧値の差（Ａ１－Ａ２）や、電圧値の比（Ａ１／Ａ２）を用いて、異物の有無の判定を行うことができる。 As another example, there is a method of making the judgment using the slope of the line connecting points 601 and 602, which is calculated by ( A1 - A2 )/( T2 - T1 ).In addition, if the times ( T1 and T2 ) at which the attenuation state of the voltage values is measured are fixed, the presence or absence of a foreign object can be judged using the difference in the voltage values ( A1 - A2 ) or the ratio of the voltage values ( A1 / A2 ).
　あるいは、送電を停止した直後の電圧値Ａ１が一定であるとした場合、所定の時間経過後の電圧値Ａ２を用いて、異物の有無の判定を行うことができる。あるいは、電圧値Ａ１が所定の電圧値Ａ２となるまでの経過時間（Ｔ２－Ｔ１）を用いて、異物の有無の判定を行うことができる。 Alternatively, if the voltage value A1 immediately after the power transmission is stopped is constant, the presence or absence of a foreign object can be determined using the voltage value A2 after a predetermined time has elapsed. Alternatively, the presence or absence of a foreign object can be determined using the time ( T2 - T1 ) that has elapsed until the voltage value A1 reaches the predetermined voltage value A2 .
　波形減衰法では、例えば送電停止期間中の波形の減衰状態によって異物の有無を判定することが可能である。減衰状態を表す指標を、本実施形態では「波形減衰指標」と総称する。上記式１で算出されるＱ値は、送電に係る電圧値の減衰状態を表す値であり、「波形減衰指標」に含まれる。 In the waveform attenuation method, it is possible to determine the presence or absence of a foreign object, for example, based on the attenuation state of the waveform during a period when power transmission is stopped. In this embodiment, the indices that represent the attenuation state are collectively referred to as "waveform attenuation indices." The Q value calculated by the above formula 1 is a value that represents the attenuation state of the voltage value related to power transmission, and is included in the "waveform attenuation indices."
　波形減衰指標はいずれも、波形減衰率に対応する値であるので、波形減衰率そのものを波形減衰指標として測定してもよい。本開示では、波形減衰率を波形減衰指標として用いる場合を説明するが、その他の波形減衰指標を用いる場合でも本実施形態の内容を同様に適用できる。 Since each waveform decay index is a value corresponding to the waveform decay rate, the waveform decay rate itself may be measured as the waveform decay index. In this disclosure, a case where the waveform decay rate is used as the waveform decay index is described, but the contents of this embodiment can be similarly applied even when other waveform decay indexes are used.
　また図８の縦軸を、送電アンテナ１０５に印加される高周波電圧の電圧値の軸として説明したが、図８の縦軸を、送電アンテナ１０５を流れる電流値としてもよい。電圧値の場合と同様に、送電停止期間中の電流値の減衰状態が異物の有無によって変化する。異物が存在する場合には、異物が存在しない場合よりも波形減衰率が高くなる。 In addition, while the vertical axis in FIG. 8 has been described as the axis representing the voltage value of the high-frequency voltage applied to the power transmitting antenna 105, the vertical axis in FIG. 8 may also represent the current value flowing through the power transmitting antenna 105. As with the voltage value, the attenuation state of the current value during the power transmission stop period changes depending on the presence or absence of a foreign object. When a foreign object is present, the waveform attenuation rate is higher than when no foreign object is present.
　よって、送電アンテナ１０５を流れる電流値の時間変化に関して、上述と同様の方法を適用して異物を検出することができる。すなわち、電流波形より算出されるＱ値、電流値の減衰の傾き、電流値の差、電流値の比、電流値の絶対値、または電流値が所定値になるまでの時間等を波形減衰指標として用いて異物の有無を判定し、異物検出を行うことができる。 Therefore, a foreign object can be detected by applying the same method as described above to the change over time in the value of the current flowing through the power transmitting antenna 105. That is, the Q value calculated from the current waveform, the slope of the current value attenuation, the current value difference, the current value ratio, the current value absolute value, or the time until the current value reaches a predetermined value, etc., can be used as waveform attenuation indicators to determine the presence or absence of a foreign object and perform foreign object detection.
　また、電圧値の減衰状態と電流値の減衰状態の両方に基づく方法がある。この方法では、電圧値の波形減衰指標と電流値の波形減衰指標とから算出される評価値を用いて異物の有無を判定することができる。なお、送電の一時停止期間の波形減衰指標を測定する例に限定されることはない。 There is also a method based on both the attenuation state of the voltage value and the attenuation state of the current value. With this method, the presence or absence of a foreign object can be determined using an evaluation value calculated from the waveform attenuation index of the voltage value and the waveform attenuation index of the current value. Note that this is not limited to the example of measuring the waveform attenuation index during a period when power transmission is temporarily suspended.
　ＴＸが電源部１０２から供給される電力を所定の電力レベルからそれより低い電力レベルまで一時的に下げた期間の波形減衰指標を測定してもよい。また、上述の例では、ＴＸが送電を制限する期間における２つの時点での電圧値または電流値が測定される構成としたが、３つ以上の時点での電圧値または電流値の測定を行ってもよい。 The waveform attenuation index may be measured during the period in which the TX temporarily reduces the power supplied from the power supply unit 102 from a predetermined power level to a lower power level. In the above example, the voltage or current values are measured at two points in time during the period in which the TX limits power transmission, but the voltage or current values may be measured at three or more points in time.
　図９を参照して、波形減衰法による異物検出方法について説明する。図９は送電波形の例を示し、横軸は時間軸であり、縦軸は送電アンテナ１０５の電圧値または電流値を表す。ＴＸが送電を開始した直後の過渡応答期間には、送電波形が安定しないので、ＲＸはＴＸに対して振幅変調または負荷変調による通信を行わない。 With reference to Figure 9, a foreign object detection method using the waveform attenuation method will be described. Figure 9 shows an example of a transmission waveform, with the horizontal axis representing time and the vertical axis representing the voltage value or current value of the transmission antenna 105. During the transient response period immediately after the TX starts transmitting power, the transmission waveform is not stable, so the RX does not communicate with the TX by amplitude modulation or load modulation.
　また、ＴＸはＲＸに対して周波数偏移変調による通信を行わない。以降、この期間を通信禁止期間と呼ぶ。なお、通信禁止期間中にＴＸはＲＸに対して送電を行う。通信禁止期間を経てＴＸはＲＸに対して安定して送電を行う。以降、この期間を送電期間と呼ぶ。 In addition, TX does not communicate with RX using frequency shift keying. Hereinafter, this period is referred to as the communication prohibition period. During the communication prohibition period, TX transmits power to RX. After the communication prohibition period, TX transmits power stably to RX. Hereinafter, this period is referred to as the power transmission period.
　ＴＸは、ＲＸから異物検出の実行要求パケット（コマンド）を受信した場合、所定期間の経過後に送電を一時停止するか、または送電電力を一時低下させる。以降、この所定期間を準備期間と呼ぶ。異物検出の実行要求パケットは上記ＲＰ０、ＲＰ１、またはＲＰ２であってもよい。ＴＸの送電制御部３０２により送電が停止し、または送電電力が一時低下すると、送電波形の振幅は減衰する。 When the TX receives a request packet (command) to execute foreign object detection from the RX, it suspends power transmission after a predetermined period of time has elapsed or temporarily reduces the transmission power. Hereinafter, this predetermined period will be referred to as the preparation period. The request packet to execute foreign object detection may be RP0, RP1, or RP2 as described above. When the power transmission control unit 302 of the TX stops power transmission or temporarily reduces the transmission power, the amplitude of the transmitted wave attenuates.
　以降、送電が制限（一時停止または送電電力の一時低下）される時点から送電の再開時点までの期間を、送電電力制御期間と呼ぶ。ＴＸは減衰する送電波形の波形減衰指標を算出し、算出した波形減衰指標の値と所定の閾値を比較し、異物の有無、あるいは異物が存在する可能性（存在確率）を判定する。 Hereinafter, the period from when power transmission is restricted (temporarily suspended or temporarily reduced transmission power) to when power transmission is resumed is referred to as the transmission power control period. The TX calculates the waveform attenuation index of the attenuating transmission wave waveform, compares the calculated waveform attenuation index value with a predetermined threshold value, and determines the presence or absence of a foreign object, or the possibility (probability of presence) of a foreign object.
　以下では、この判定を異物判定という。異物判定は、送電電力制御期間中に実施されるか、また、通信禁止期間や送電期間に実施されてもよい。送電電力制御期間の経過後、異物判定の結果、異物が存在しないか、または異物が存在する可能性が低いと判定された場合、ＴＸは送電を再開する。送電の再開直後の過渡応答期間には送電波形が安定しないので、再度通信禁止期間となり、その後に送電期間に移行する。 Hereinafter, this determination will be referred to as foreign object determination. Foreign object determination may be performed during the transmission power control period, or may be performed during the communication prohibited period or power transmission period. After the transmission power control period has elapsed, if the result of the foreign object determination indicates that no foreign object is present or that the possibility of a foreign object being present is low, the TX resumes power transmission. Since the transmission waveform is not stable during the transient response period immediately after power transmission is resumed, the communication prohibited period will begin again, and then the power transmission period will begin.
　以上のようにＴＸは、送電開始から通信禁止期間、送電期間、送電電力制御期間での処理を繰り返し実行する。ＴＸは、所定のタイミングで算出した波形減衰指標の値を閾値と比較して異物判定を行う。なお、送電電力制御期間にて、受電装置４０１の受電アンテナ２０５と共振コンデンサ２１１に、受電部２０３、充電部２０６、およびバッテリ２０７等の要素が接続されていると、波形減衰指標は、これらの要素による負荷の影響を受ける。 As described above, the TX repeatedly executes processing from the start of power transmission through the communication prohibition period, power transmission period, and power transmission power control period. The TX compares the value of the waveform attenuation index calculated at a specified timing with a threshold value to determine whether a foreign object is present. Note that during the power transmission power control period, if elements such as the power receiving unit 203, charging unit 206, and battery 207 are connected to the power receiving antenna 205 and resonant capacitor 211 of the power receiving device 401, the waveform attenuation index is affected by the load of these elements.
　受電部２０３、充電部２０６、およびバッテリ２０７の状態によって波形減衰指標が変化することになる。そのため、波形減衰指標の値が大きい理由が異物による影響であるのか、受電部２０３、充電部２０６、バッテリ２０７等の状態変化によるのかの区別が困難になる。そこで、波形減衰指標に基づく異物検出を行う場合、ＲＸは準備期間中に第１スイッチ部２０９を切断（ＯＦＦ）状態とする。 The waveform attenuation index changes depending on the state of the power receiving unit 203, the charging unit 206, and the battery 207. Therefore, it becomes difficult to distinguish whether a large value of the waveform attenuation index is due to the influence of a foreign object or due to a change in the state of the power receiving unit 203, the charging unit 206, the battery 207, etc. Therefore, when detecting a foreign object based on the waveform attenuation index, the RX sets the first switch unit 209 to a disconnected (OFF) state during the preparation period.
　これにより、バッテリ２０７の影響を抑制することが可能である。あるいはＲＸは、第２スイッチ部２１０をＯＮにして短絡し、受電アンテナ２０５、共振コンデンサ２１１、および第２スイッチ部２１０で形成される閉回路に電流が流れる状態とする。これにより、受電部２０３、充電部２０６、およびバッテリ２０７の影響を抑制することが可能になる。ＲＸはＴＸに対して異物検出の実行パケット（コマンド）を送信し、上記処理を実行する。 This makes it possible to suppress the influence of the battery 207. Alternatively, the RX turns on the second switch unit 210 to short-circuit it, allowing current to flow through the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210. This makes it possible to suppress the influence of the power receiving unit 203, the charging unit 206, and the battery 207. The RX sends a foreign object detection execution packet (command) to the TX, and executes the above process.
　第１スイッチ部２０９または第２スイッチ部２１０、あるいはその両方の制御により取得される送電波形の波形減衰指標に基づいて、より精度の高い異物検出が可能となる。あるいは、ＲＸは準備期間中に、第１スイッチ部２０９をＯＮにして短絡し、第２スイッチ部２１０をＯＦＦにして切断した状態において、低消費電力モードに移行するか、あるいは消費電力が一定になるように制御してもよい。 More accurate foreign object detection is possible based on the waveform attenuation index of the transmitted radio wave acquired by controlling the first switch unit 209 or the second switch unit 210, or both. Alternatively, during the preparation period, the RX may transition to a low power consumption mode or control the power consumption to be constant while the first switch unit 209 is turned ON to short circuit and the second switch unit 210 is turned OFF to disconnect.
　ＲＸでの消費電力が一定でない場合や、大きな電力が消費される場合には、波形減衰指標は消費電力の変動の影響を受ける。そのため、ＲＸはソフトウェアアプリケーションの動作を制限（停止を含む）するか、あるいはハードウェア機能ブロック要素を低消費電力モードに設定するか、あるいは動作停止モードに設定する。ＲＸの消費電力を抑制した状態で測定される波形減衰指標を用いることで、より精度の高い異物検出が可能となる。 If the power consumption in the RX is not constant or if a large amount of power is consumed, the waveform attenuation index is affected by the fluctuations in power consumption. For this reason, the RX limits (including halting) the operation of software applications, or sets hardware function block elements to a low power consumption mode or a stopped operation mode. By using the waveform attenuation index measured with the RX power consumption suppressed, more accurate foreign object detection is possible.
　一方、ＴＸはＲＸから異物検出の実行パケット（コマンド）を受信した場合、準備期間中にスイッチ部１０８をＯＮにして短絡し、送電アンテナ１０５、共振コンデンサ１０７、およびスイッチ部１０８で形成される閉回路に電流が流れる状態とする。 On the other hand, when the TX receives a foreign object detection execution packet (command) from the RX, it turns on the switch unit 108 during the preparation period, shorting it, and causes a current to flow through the closed circuit formed by the power transmitting antenna 105, the resonant capacitor 107, and the switch unit 108.
　これにより、電源部１０２、送電部１０３、および通信部１０４による影響を抑制することが可能である。あるいは、送電アンテナ１０５と送電部１０３との間にスイッチ（不図示）を設け、準備期間中に当該スイッチを切断することで電源部１０２、送電部１０３、および通信部１０４による影響を抑制することが可能である。 This makes it possible to suppress the effects of the power supply unit 102, the power transmission unit 103, and the communication unit 104. Alternatively, by providing a switch (not shown) between the power transmission antenna 105 and the power transmission unit 103 and turning off the switch during the preparation period, it is possible to suppress the effects of the power supply unit 102, the power transmission unit 103, and the communication unit 104.
　続いて、波形減衰法を用いる場合の各期間の決定方法について説明する。まず、準備期間の決定方法として、下記の方法がある。
・第１の決定方法：予め決められた所定時間に決定する方法。
・第２の決定方法：ＴＸがその状態に応じて期間の長さを所定時間に決定してＲＸに通知するか、または、ＲＸがその状態に応じて期間の長さを所定時間に決定してＴＸに通知する方法。
・第３の決定方法：ＴＸとＲＸは互いに通信を行って期間の長さを決定する方法。 Next, a method for determining each period when the waveform decay method is used will be described. First, the preparation period can be determined in the following manner.
First determination method: A method of determining at a predetermined time.
Second determination method: The TX determines the length of the period to a predetermined time depending on its state and notifies the RX, or the RX determines the length of the period to a predetermined time depending on its state and notifies the TX.
Third determination method: TX and RX communicate with each other to determine the length of the period.
　第３の決定方法では、例えばＴＸが決定した最大時間をＲＸに通知し、ＲＸが決定した最小時間をＴＸに通知する。ＴＸとＲＸが設定した範囲内で準備期間の長さをＲＸ（またはＴＸ）が決定して、決定した時間をＴＸ（またはＲＸ）に通知する。準備期間の長さを適切な時間に設定することによって、送電電力制御期間での波形の乱れを抑制可能である。 In the third determination method, for example, the TX notifies the RX of the maximum time it has determined, and the RX notifies the TX of the minimum time it has determined. The RX (or TX) determines the length of the preparation period within a range set by the TX and RX, and notifies the TX (or RX) of the determined time. By setting the length of the preparation period to an appropriate time, it is possible to suppress waveform disturbance during the transmission power control period.
　次に送電電力制御期間の決定方法について説明する。ＴＸとＲＸの双方で対応可能な送電電力制御期間を決定することが重要である。そのために、Ｎｅｇｏｔｉａｔｉｏｎ　ＰｈａｓｅにてＴＸとＲＸは互いに対応可能な送電電力制御期間に対する能力情報を通知し合うことで、双方の共通範囲の中から実際の送電電力制御期間を決定することができる。 Next, we will explain how to determine the transmission power control period. It is important to determine a transmission power control period that is compatible with both the TX and RX. To achieve this, in the Negotiation Phase, the TX and RX notify each other of their capability information for the transmission power control period that they can support, and can then determine the actual transmission power control period from within the common range of both.
　具体的には、ＲＸが発行する２種類のコマンドを用いて実現される。第１のコマンドは、ＴＸが対応可能な、送電電力制御の最小期間の情報を取得するコマンドである。第２のコマンドは、ＲＸが対応可能な、送電電力制御の最大期間の情報を通知するコマンドである。第１および第２のコマンドにより、ＲＸとＴＸは互いの送電電力制御期間に関する能力を把握することができる。 Specifically, this is achieved by using two types of commands issued by the RX. The first command is a command to obtain information on the minimum period of transmission power control that the TX can handle. The second command is a command to notify information on the maximum period of transmission power control that the RX can handle. The first and second commands allow the RX and TX to understand each other's capabilities regarding the transmission power control period.
　「ＴＸでの送電電力制御の最小期間≧ＲＸでの送電電力制御の最大期間」という条件が満たされる場合、これらの期間に基づく範囲内で送電電力制御期間を選択することが可能である。また上記コマンドの送受において、波形減衰法による異物検出を実施しない場合、コマンドに設定される上記最小期間や最大期間の値は「０」に設定される。このようにすることで、ＴＸとＲＸは波形減衰法による異物検出を行わないことを通知することが可能である。 If the condition "minimum period of transmission power control in TX ≧ maximum period of transmission power control in RX" is met, it is possible to select the transmission power control period within a range based on these periods. Furthermore, if foreign object detection using the waveform attenuation method is not performed when sending and receiving the above command, the values of the above minimum and maximum periods set in the command are set to "0". In this way, it is possible for the TX and RX to notify that foreign object detection using the waveform attenuation method will not be performed.
　また、送電電力と送電電力制御期間との関係について説明する。送電電力が小さい第１の状態と送電電力が大きい第２の状態とを比較した場合、第２の状態の方が送電電力制御期間は短い。送電電力制御期間を経て送電を再開すると、送電を再開したタイミングで送電波形にリンギングが発生する可能性がある。 The relationship between the transmission power and the transmission power control period will now be explained. When comparing a first state in which the transmission power is small with a second state in which the transmission power is large, the transmission power control period is shorter in the second state. When power transmission is resumed after the transmission power control period, ringing may occur in the transmission waveform at the timing when power transmission is resumed.
　送電再開時の送電電力の高低差が大きいほど、より大きなリンギングが発生する。リンギングの抑制には、送電電力の高低差を小さくすることが必要である。送電電力制御期間が短いと、送電波形の減衰が小さい状態で送電が再開するので、結果として送電電力の高低差が小さくなり、リンギングを抑制することが可能となる。 The greater the difference in the transmitted power when transmission resumes, the greater the ringing that occurs. To suppress ringing, it is necessary to reduce the difference in the transmitted power. If the transmission power control period is short, transmission resumes with little attenuation of the transmitted radio wave, which results in a smaller difference in the transmitted power and makes it possible to suppress ringing.
　送電電力が大きいほど、送電電力制御期間を短くすることで、送電再開時の送電電力の高低差を小さくし、リンギングを抑制することが可能となる。あるいは、送電電力が小さい時よりも大きい時の方が、送電電力制御期間を長くする方法がある。送電電力が大きい時には高精度な異物検出が求められる。この場合、送電電力制御期間を長く設定して送電波形の減衰状態が長時間にわたって測定される。これにより、送電電力が小さい時に比較してより高精度な異物検出を実現可能である。 The higher the transmission power, the shorter the transmission power control period can be set, which reduces the difference in transmission power when transmission resumes and suppresses ringing. Alternatively, one method is to make the transmission power control period longer when the transmission power is high than when it is low. When the transmission power is high, highly accurate foreign object detection is required. In this case, the transmission power control period is set long and the attenuation state of the transmitted radio wave is measured over a long period of time. This makes it possible to achieve more accurate foreign object detection compared to when the transmission power is low.
　次に通信禁止期間の決定方法について説明する。通信禁止期間の目的は、送電の開始または再開後に発生するリンギングに関して、ＴＸとＲＸが通信を行わないようにすることである。通信禁止期間の決定方法は、上記第１乃至第３の決定方法と同様である。例えば、第３の決定方法では、ＴＸとＲＸが通信により設定した範囲のうち、通信禁止期間の長さを最小または最大の時間に決定することが可能である。 Next, a method for determining the communication prohibition period will be explained. The purpose of the communication prohibition period is to prevent the TX and RX from communicating with each other regarding ringing that occurs after the start or restart of power transmission. The method for determining the communication prohibition period is the same as the first to third determination methods described above. For example, with the third determination method, it is possible to determine the length of the communication prohibition period to be the minimum or maximum time within the range set by the TX and RX through communication.
　また、送電電力と通信禁止期間との関係について説明する。送電電力が小さい第１の状態と送電電力が大きい第２の状態とを比較した場合、第２の状態の方が通信禁止期間は長い。送電電力制御期間を経て送電が再開されると、送電再開のタイミングで送電波形にリンギングが発生する可能性がある。 The relationship between the transmission power and the communication prohibition period will now be explained. When comparing a first state in which the transmission power is low with a second state in which the transmission power is high, the communication prohibition period is longer in the second state. When power transmission is resumed after a transmission power control period, there is a possibility that ringing will occur in the transmission waveform at the timing of the resumption of power transmission.
　送電再開時の送電電力の高低差が大きいほど、大きなリンギングが発生する。そこで通信禁止期間を長くすることでリンギングが収束するか、また十分小さくなってからＴＸとＲＸは安定した通信を行うことが可能となる。あるいは、送電電力が小さい時よりも大きい時の方が、通信禁止期間を短くする方法がある。 The greater the difference in transmission power when transmission resumes, the greater the ringing that occurs. Therefore, by lengthening the communication prohibition period, the ringing will converge or become sufficiently small, allowing the TX and RX to communicate stably. Alternatively, there is a method to shorten the communication prohibition period when the transmission power is large rather than when it is small.
　また、送電電力制御期間と通信禁止期間との関係について説明する。送電電力制御期間が長くなるほど、通信禁止期間が長くなるように決定される。上述したように送電再開時の送電電力の高低差が大きいほど、大きなリンギングが発生する。送電電力制御期間が長くなると、送電波形の減衰量は大きくなる。 The relationship between the transmission power control period and the communication prohibition period will now be explained. The communication prohibition period is determined to be longer as the transmission power control period becomes longer. As mentioned above, the greater the difference in the transmission power when transmission is resumed, the greater the ringing that occurs. The longer the transmission power control period, the greater the amount of attenuation of the transmitted radio wave.
　その結果として送電再開時の送電電力の高低差が大きくなり、大きなリンギングが発生する。そこで、送電電力制御期間が長くなるほど、通信禁止期間を長く設定することで、リンギングが収束するか、または十分小さくなってからＴＸとＲＸが安定した通信を行うことが可能となる。あるいは、送電電力制御期間が長くなるほど、通信禁止期間を短くする方法がある。 As a result, the difference in transmission power when transmission resumes becomes large, causing significant ringing. Therefore, by setting a longer communication prohibition period as the transmission power control period becomes longer, it becomes possible for the TX and RX to carry out stable communication once the ringing has converged or become sufficiently small. Alternatively, there is a method of shortening the communication prohibition period as the transmission power control period becomes longer.
　次に、送電期間の決定方法について説明する。当該期間の決定方法は、上記第１乃至第３の決定方法と同様である。例えば、第３の決定方法では、ＴＸが決定した最大時間をＲＸに通知し、ＲＸが決定した最小時間をＴＸに通知する。ＴＸとＲＸが設定した範囲内でＲＸ（またはＴＸ）が送電期間の長さを決定してＴＸ（またはＲＸ）に通知する。 Next, a method for determining the power transmission period will be described. The method for determining the period is the same as the first to third determination methods described above. For example, in the third determination method, the TX notifies the RX of the maximum time it has determined, and the RX notifies the TX of the minimum time it has determined. The RX (or TX) determines the length of the power transmission period within a range set by the TX and RX, and notifies the TX (or RX).
　また、送電電力と送電期間との関係について説明する。送電電力が小さい第１の状態と送電電力が大きい第２の状態とを比較した場合、第２の状態の方が送電期間は短い。送電電力が大きくなるほど、より高い異物検出精度が求められる。 The relationship between the transmission power and the transmission period will now be explained. When comparing a first state in which the transmission power is small with a second state in which the transmission power is large, the transmission period is shorter in the second state. The higher the transmission power, the higher the foreign object detection accuracy required.
　よって、送電電力が大きくいほど送電期間を短くすることにより、所定時間内の送電電力制御期間の回数を増加させる制御が行われる。送電波形の減衰状態の測定回数が増加し、異物検出の機会が増加する。したがって、より高精度な異物検出が可能となる。あるいは、送電電力が大きいほど送電期間を長くする方法がある。この方法によれば、ＴＸからＲＸへの電力伝送効率を低下させることなく、送電を行うことが可能である。 Therefore, the higher the transmission power, the shorter the transmission period, thereby increasing the number of transmission power control periods within a given time. This increases the number of times the attenuation state of the transmitted radio wave is measured, increasing the opportunities for foreign object detection. This allows for more accurate foreign object detection. Alternatively, there is a method in which the higher the transmission power, the longer the transmission period is. With this method, it is possible to transmit power without reducing the efficiency of power transmission from TX to RX.
　続いて、波形減衰法における異物判定の閾値設定方法を説明する。波形減衰指標の測定値を所定の閾値を比較し、比較結果に基づいて異物判定が可能である。第１の閾値設定方法は、閾値として、送電対象となるＲＸに依存しない共通の値である、予め定められた値をＴＸが保持する方法である。 Next, we will explain how to set the threshold for foreign object detection in the waveform attenuation method. The measured value of the waveform attenuation index is compared with a predetermined threshold, and a foreign object can be detected based on the comparison result. The first threshold setting method is a method in which the TX holds a predetermined value as the threshold, which is a common value that does not depend on the RX to which power is transmitted.
　この閾値は固定値、または、状況に応じてＴＸが決定する可変値である。送電電力制御期間中の送電波形は、異物が存在すると波形減衰率が高くなる。よって、異物が存在しない状態で取得される波形減衰指標の値を予め保持しておき、この値が閾値として設定される。波形減衰指標の測定値と閾値との比較により、「異物有り」あるいは「異物が存在する可能性が高い」と判定することができる。 This threshold is a fixed value, or a variable value determined by the TX depending on the situation. If a foreign object is present, the waveform attenuation rate of the transmission waveform during the transmission power control period increases. Therefore, the value of the waveform attenuation index obtained when no foreign object is present is stored in advance, and this value is set as the threshold. By comparing the measured value of the waveform attenuation index with the threshold, it is possible to determine that "a foreign object is present" or "there is a high possibility that a foreign object is present."
　例えば、波形減衰指標としてＱ値を採用する場合、ＴＸはＱ値の測定値と、予め定められた閾値とを比較する。閾値は異物が存在しない状態での測定値または当該測定値に対して測定誤差を加味した値に基づいて設定される。Ｑ値の測定値が閾値よりも小さい場合、「異物有り」あるいは「異物が存在する可能性が高い」と判定される。Ｑ値の測定値が閾値以上である場合、「異物無し」あるいは「異物が存在する可能性は低い」と判定される。 For example, when the Q value is used as the waveform attenuation index, the TX compares the measured Q value with a predetermined threshold value. The threshold value is set based on the measured value when no foreign object is present or on the measured value that takes into account measurement error. If the measured Q value is smaller than the threshold value, it is determined that "foreign object is present" or "there is a high possibility that a foreign object is present." If the measured Q value is equal to or greater than the threshold value, it is determined that "no foreign object is present" or "there is a low possibility that a foreign object is present."
　第２の閾値設定方法は、ＲＸから送信される情報に基づいてＴＸが閾値を調整して決定する方法である。第１の閾値設定方法との相違点として留意すべきことは、波形減衰指標の値が、ＴＸに載置される、送電対象のＲＸによって異なる可能性があるということである。 The second threshold setting method is a method in which the TX adjusts and determines the threshold based on information transmitted from the RX. A notable difference from the first threshold setting method is that the value of the waveform attenuation index may differ depending on the RX that is the target of power transmission and is placed on the TX.
　その理由は、ＴＸの送電アンテナを介して電磁的に結合するＲＸの電気特性が、波形減衰指標の値に影響を与えるからである。例えば、波形減衰指標としてＱ値を採用する場合、異物が存在しないときにＴＸが測定するＱ値は、ＴＸに載置されるＲＸによって異なる可能性がある。そこでＲＸは、異物が存在しない状態でＴＸに載置された際のＱ値情報をＴＸごとに保持しておき、Ｑ値情報をＴＸに通知する。ＴＸはＲＸから受信したＱ値情報に基づいてＲＸごとに閾値を調整して決定する。 The reason is that the electrical characteristics of the RX, which is electromagnetically coupled via the TX's power transmission antenna, affect the value of the waveform attenuation index. For example, if the Q value is used as the waveform attenuation index, the Q value measured by the TX when no foreign object is present may differ depending on the RX placed on the TX. Therefore, the RX stores Q value information for each TX when placed on the TX in the absence of a foreign object, and notifies the TX of the Q value information. The TX adjusts and determines the threshold for each RX based on the Q value information received from the RX.
　より具体的には、ＴＸは、Ｎｅｇｏｔｉａｔｉｏｎ　ＰｈａｓｅにてＲｅｆｅｒｅｎｃｅ　Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ　Ｖａｌｕｅの情報を含むＦＯＤ　Ｓｔａｔｕｓ　Ｄａｔａ　Ｐａｃｋｅｔを受信し、Ｑ値計測法における閾値を調整して決定する。 More specifically, the TX receives a FOD Status Data Packet containing Reference Quality Factor Value information during the Negotiation Phase, and adjusts and determines the threshold value in the Q-value measurement method.
　Ｒｅｆｅｒｅｎｃｅ　Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ　Ｖａｌｕｅは、異物が存在しない状態でＲＸがＴＸに載置された際のＱ値情報に相当する。よって、ＴＸはＲｅｆｅｒｅｎｃｅ　Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ　Ｖａｌｕｅに基づいて調整を行い、波形減衰法による異物判定用の閾値を決定する。 The Reference Quality Factor Value corresponds to the Q value information when the RX is placed on the TX in the absence of any foreign object. Therefore, the TX performs adjustments based on the Reference Quality Factor Value and determines the threshold value for foreign object detection using the waveform attenuation method.
　なお、当該ＰｈａｓｅにてＲＸからＴＸに送信されるＲｅｆｅｒｅｎｃｅ　Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ　Ｖａｌｕｅは、本来周波数領域でＱ値を計測する、Ｑ値計測法における異物検出に用いる情報である。しかし、波形減衰指標としてＱ値を用いる場合、Ｑ値の導出方法は異なるが、時間領域でＱ値を計測する波形減衰法によっても、例えば図８の波形から上記式１によってＱ値を求めることができる。 The Reference Quality Factor Value transmitted from RX to TX in this Phase is information used for foreign object detection in the Q-value measurement method, which originally measures the Q-value in the frequency domain. However, when the Q-value is used as a waveform attenuation index, the Q-value can be derived in a different way, but the Q-value can also be calculated from the waveform in Figure 8, for example, using the above formula 1, using the waveform attenuation method, which measures the Q-value in the time domain.
　そのため、Ｒｅｆｅｒｅｎｃｅ　Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ　Ｖａｌｕｅに基づいて、波形減衰法のＱ値の閾値を設定することは可能である。なお、Ｒｅｆｅｒｅｎｃｅ　Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ　Ｖａｌｕｅに対して所定値（測定誤差に対応する値）を加味した波形減衰指標の値を、異物判定用の閾値として設定してもよい。 Therefore, it is possible to set the Q value threshold of the waveform attenuation method based on the Reference Quality Factor Value. Note that the value of the waveform attenuation index, which takes into account a specified value (a value corresponding to the measurement error) for the Reference Quality Factor Value, may be set as the threshold for foreign object determination.
　このようにＮｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅで既にＲＸからＴＸに送信された情報に基づき、ＴＸが波形減衰法のＱ値の閾値を設定することで、閾値設定のための新たな測定等を行う必要がなくなる。この結果、より短時間で閾値の設定が可能となる。設定後の閾値とＱ値の測定値に基づく異物判定については上述のとおりである。 In this way, the TX sets the Q-value threshold for the waveform attenuation method based on the information already sent from the RX to the TX in the Negotiation Phase, eliminating the need to perform new measurements to set the threshold. As a result, the threshold can be set in a shorter time. Foreign object determination based on the measured value of the threshold and Q-value after the setting is as described above.
　第３の閾値設定方法は、異物が存在しない状態でＴＸが波形減衰指標を測定し、その測定結果の情報に基づいて、ＴＸが閾値を調整して決定する方法である。波形減衰指標の値は送電電力によって異なる可能性がある。 The third threshold setting method is a method in which the TX measures the waveform attenuation index in the absence of foreign objects, and adjusts and determines the threshold based on the information from the measurement results. The value of the waveform attenuation index may differ depending on the transmission power.
　その理由は、送電電力の大小によって発熱量やＴＸの電気回路の諸特性等が変化し、それらが波形減衰指標の値に影響を与えるからである。そこでＴＸは送電電力ごとの波形減衰指標を測定し、測定結果に基づいて閾値を調整して決定することで、より高精度な異物検出が可能となる。 The reason for this is that the amount of heat generated and the various characteristics of the TX's electrical circuitry change depending on the level of transmitted power, which affects the value of the waveform attenuation index. Therefore, the TX measures the waveform attenuation index for each transmitted power and adjusts and determines the threshold based on the measurement results, enabling more accurate foreign object detection.
　図１０は、波形減衰法におけるＴＸの送電電力ごとの異物判定用の閾値設定方法を説明するための図である。図１０にて、横軸は送電装置の送電電力を表し、縦軸は送電電圧波形または送電電流波形の波形減衰指標（波形減衰率）を表す。 FIG. 10 is a diagram for explaining a method for setting a threshold for foreign object determination for each TX transmission power in the waveform attenuation method. In FIG. 10, the horizontal axis represents the transmission power of the power transmission device, and the vertical axis represents the waveform attenuation index (waveform attenuation rate) of the transmission voltage waveform or transmission current waveform.
　直線状の線分９０２で示されるグラフ線上にて、点９００は送電電力値Ｐｔ１および波形減衰指標δ１に対応し、点９０１は送電電力値Ｐｔ２および波形減衰指標δ２に対応する。当該グラフ線上にて、点９０３は送電電力値Ｐｔ３および波形減衰指標δ３に対応する。 On the graph line indicated by the straight line segment 902, point 900 corresponds to the transmission power value Pt1 and the waveform attenuation index δ1, and point 901 corresponds to the transmission power value Pt2 and the waveform attenuation index δ2. On the graph line, point 903 corresponds to the transmission power value Pt3 and the waveform attenuation index δ3.
　まず、ＲＸは、ＴＸから送電があった場合にＲＸが軽負荷状態になるように制御する。軽負荷状態ではＲＸの負荷に電力が供給されないか、あるいは、閾値未満の電力しか供給されない状態となる。この状態でのＴＸの送電電力値をＰｔ１とする。そして、ＴＸは軽負荷状態で送電を停止させるか、または送電電力を低下させて、波形減衰指標δ１を測定する。 First, the RX controls the RX so that it is in a light-load state when power is transmitted from the TX. In a light-load state, either no power is supplied to the RX load, or only power below a threshold is supplied. The transmission power value of the TX in this state is Pt1. Then, the TX stops transmitting power in a light-load state, or reduces the transmission power, and measures the waveform attenuation index δ1.
　このとき、ＴＸは送電電力値Ｐｔ１を認識しており、送電電力値Ｐｔ１と波形減衰指標δ１とを関連付けるＣＰ９００をメモリに記憶しておく。次にＲＸは負荷接続状態の制御を行う。負荷接続状態は、例えばＴＸから送電があった場合にＲＸの負荷に最大電力が供給されるか、あるいは閾値以上の電力が供給される状態である。 At this time, the TX recognizes the transmission power value Pt1, and stores in memory CP900 that associates the transmission power value Pt1 with the waveform attenuation index δ1. Next, the RX controls the load connection state. The load connection state is, for example, a state in which, when power is transmitted from the TX, maximum power is supplied to the RX load, or power above a threshold is supplied.
　この状態でのＴＸの送電電力値をＰｔ２とする。そしてＴＸは負荷接続状態で送電を停止させるか、または送電電力を低下させて、波形減衰指標δ２を測定する。このとき、ＴＸは、送電電力値Ｐｔ２と波形減衰指標δ２とを関連づけるＣＰ９０１をメモリに記憶しておく。続いて、ＴＸはＣＰ９００とＣＰ９０１との間を直線補間して線分９０２を生成する。線分９０２は、ＴＸとＲＸの周辺に異物が存在しない状態における送電電力と送電波形の波形減衰指標との関係を示している。 The transmission power value of the TX in this state is Pt2. The TX then stops transmission while connected to a load, or reduces the transmission power, and measures the waveform attenuation index δ2. At this time, the TX stores in memory CP901, which associates the transmission power value Pt2 with the waveform attenuation index δ2. Next, the TX generates line segment 902 by linearly interpolating between CP900 and CP901. Line segment 902 shows the relationship between the transmission power and the waveform attenuation index of the transmitted wave when no foreign object is present around the TX and RX.
　よって、ＴＸは線分９０２に基づき、当該状態における、送電電力値ごとの波形減衰指標を推定することができる。例えば、送電電力値Ｐｔ３の場合、Ｐｔ３に対応する線分９０２上の点９０３から、波形減衰指標がδ３と推定される。ＴＸは推定結果に基づき、送電電力値ごとの、異物判定用の閾値を算出することが可能である。 The TX can therefore estimate the waveform attenuation index for each transmission power value in that state based on line segment 902. For example, in the case of a transmission power value Pt3, the waveform attenuation index is estimated to be δ3 from point 903 on line segment 902 that corresponds to Pt3. The TX can calculate a threshold value for foreign object determination for each transmission power value based on the estimation result.
　例えば、ある送電電力値における、異物が存在しない状態での波形減衰指標の推定結果に対して、所定値（測定誤差に対応する値）を加味した波形減衰指標を、異物判定用の閾値として設定することができる。 For example, the waveform attenuation index estimated for a certain transmission power value when no foreign object is present can be adjusted by adding a predetermined value (a value corresponding to the measurement error) to the waveform attenuation index, and this can be set as the threshold for determining whether or not a foreign object is present.
　送電装置４０２が送電電力値と波形減衰指標との組み合わせを取得するために、送電装置４０２と受電装置４０１とが行うＣＡＬ処理を、以下では「波形減衰法のＣＡＬ処理」と呼ぶ。なお、上述の例では、送電電力値Ｐｔ１とＰｔ２という２ポイントの測定を行ったが、より精度を高めるために、３以上のポイントで測定を実施して各送電電力の波形減衰指標を算出してもよい。 The CAL processing performed by the power transmitting device 402 and the power receiving device 401 in order for the power transmitting device 402 to obtain a combination of the transmitted power value and the waveform attenuation index is hereinafter referred to as the "CAL processing of the waveform attenuation method." Note that in the above example, measurements were performed at two points, the transmitted power values Pt1 and Pt2, but to improve accuracy, measurements may be performed at three or more points to calculate the waveform attenuation index for each transmitted power.
　ＲＸは軽負荷状態の制御と、負荷接続状態の制御とをそれぞれ、ＴＸに通知した後に行ってもよい。また、当該２つの制御はいずれが先に行われてもよい。 The RX may control the light load state and the load connection state after notifying the TX. Also, either of the two controls may be performed first.
　負荷ごと（または送電電力値ごと）の異物判定用閾値の算出処理は、Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅにおいて行われてもよい。上述したように、ＴＸはＣａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅにて、Ｐｏｗｅｒ　Ｌｏｓｓ法による異物検出を行う際に必要となるデータを取得する。その際、ＴＸは、ＲＸの負荷状態が軽負荷状態の場合と負荷接続状態の場合における、それぞれのＲＸの受電電力値および電力損失に関するデータを取得する。 The calculation process of the foreign object determination threshold for each load (or each transmission power value) may be performed in the calibration phase. As described above, in the calibration phase, the TX acquires data required for foreign object detection using the power loss method. At that time, the TX acquires data regarding the received power value and power loss of each RX when the RX load state is a light load state and when the RX load state is a load connected state.
　そこで、図１０におけるＣＰ９００とＣＰ９０１の測定は、Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅにおいて、ＲＸが軽負荷状態になったときと負荷接続状態になったときに、電力損失の測定と一緒に行われてもよい。 Therefore, the measurements of CP900 and CP901 in FIG. 10 may be performed together with the measurement of power loss during the calibration phase when RX is in a light load state and when it is in a load-connected state.
　例えばＴＸは、ＲＸから第１の基準受電電力情報を有する信号を受信した際に、Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅで行うべき所定の処理に加えて、ＣＰ９００の測定を行う。第１の基準受電電力情報は、ＷＰＣ規格で規定されるＲＰ１の情報であるが、他のメッセージが用いられてもよい。 For example, when the TX receives a signal having first reference received power information from the RX, in addition to the predetermined processing to be performed in the calibration phase, the TX measures CP900. The first reference received power information is the RP1 information defined in the WPC standard, but other messages may also be used.
　またＴＸは、ＲＸから第２の基準受電電力情報を有する信号を受信した際に、Ｃａｌｉｂｒａｔｉｏｎ　Ｐｈａｓｅで行うべき所定の処理に加えて、ＣＰ９０１の測定を行う。第２の基準受電電力情報は、ＷＰＣ規格で規定されるＲＰ２の情報であるが、他のメッセージが用いられてもよい。ＣＰ９００とＣＰ９０１の測定を行う期間を別途設ける必要はなくなるので、より短時間でＣＰ９００とＣＰ９０１の測定を実行できる。 When the TX receives a signal having second reference received power information from the RX, it measures CP901 in addition to the predetermined processing to be performed in the Calibration Phase. The second reference received power information is the RP2 information defined in the WPC standard, but other messages may be used. Since there is no need to set aside a separate period for measuring CP900 and CP901, the measurements of CP900 and CP901 can be performed in a shorter time.
　このようにＴＸが各送電電力で測定した波形減衰指標の情報に基づき、ＴＸが各送電電力での波形減衰指標の閾値を調整して設定する。例えば、波形減衰指標としてＱ値を用いる場合、ＴＸはＱ値の測定値と、上記方法で決定した閾値とを比較する。 In this way, based on the information of the waveform attenuation index measured by the TX at each transmission power, the TX adjusts and sets the threshold value of the waveform attenuation index at each transmission power. For example, when the Q value is used as the waveform attenuation index, the TX compares the measured value of the Q value with the threshold value determined by the above method.
　Ｑ値の測定値が閾値よりも小さい場合、「異物有り」または「異物が存在する可能性有り」と判定される。Ｑ値の測定値が閾値以上である場合、「異物無し」または「異物が存在する可能性は低い」と判定される。以上により、ＴＸの各送電電力における閾値が設定されて、より高精度な異物判定が可能となる。 If the measured Q value is smaller than the threshold, it is determined that there is a foreign object or that there is a possibility that a foreign object is present. If the measured Q value is equal to or greater than the threshold, it is determined that there is no foreign object or that there is a low possibility that a foreign object is present. In this way, thresholds are set for each TX transmission power, enabling more accurate foreign object determination.
　次に、送電アンテナと受電アンテナとの電磁的な結合状態（結合係数を含む）の測定方法を説明する。当該結合状態を表す指標（以下、結合状態指標という）の測定法の例を示す。まず、第１の測定方法について説明する。無線電力伝送では、送電アンテナ１０５と受電アンテナ２０５とを電磁結合させて送電が行われる。 Next, a method for measuring the electromagnetic coupling state (including the coupling coefficient) between the transmitting antenna and the receiving antenna will be described. An example of a method for measuring an index representing the coupling state (hereinafter, referred to as a coupling state index) will be shown. First, the first measurement method will be described. In wireless power transmission, power is transmitted by electromagnetically coupling the transmitting antenna 105 and the receiving antenna 205.
　送電アンテナ１０５に交流電流を流して、受電アンテナ２０５を貫く磁束を変化させることによって受電アンテナ２０５に電圧が誘起される。結合状態指標である結合係数（ｋと記し、その値をｋ値という）は、例えば送電アンテナで発生した磁束の全て（１００％）が受電アンテナを貫くときに「ｋ＝１」となる。 By passing an alternating current through the transmitting antenna 105 and changing the magnetic flux that penetrates the receiving antenna 205, a voltage is induced in the receiving antenna 205. The coupling coefficient (denoted as k, and its value is called the k value), which is an index of the coupling state, is "k = 1" when, for example, all (100%) of the magnetic flux generated by the transmitting antenna penetrates the receiving antenna.
　また送電アンテナで発生した磁束の７０％が受電アンテナを貫くときに「ｋ＝０．７」となる。この場合、送電アンテナで発生した残り（３０％）の磁束は漏れ磁束（漏洩磁束）となる。これは送電アンテナで発生した磁束のうち、受電アンテナを貫かなかった磁束である。 Furthermore, when 70% of the magnetic flux generated by the transmitting antenna penetrates the receiving antenna, "k = 0.7". In this case, the remaining magnetic flux (30%) generated by the transmitting antenna becomes leakage magnetic flux. This is the magnetic flux generated by the transmitting antenna that does not penetrate the receiving antenna.
　したがって、送電アンテナと受電アンテナとの結合状態が良好であってｋ値が大きいとき、ＴＸからＲＸに送電される電力の伝送効率は高い。逆に結合状態が良好でなく、ｋ値が小さいとき、ＴＸからＲＸに送電される電力の伝送効率は低い。 Therefore, when the coupling between the transmitting antenna and the receiving antenna is good and the k value is large, the transmission efficiency of the power transmitted from TX to RX is high. Conversely, when the coupling is not good and the k value is small, the transmission efficiency of the power transmitted from TX to RX is low.
　結合係数の値が低下する要因としては、送電アンテナと受電アンテナとの間に異物（金属片等）が入ることや、送電アンテナと受電アンテナとの位置ずれがある。あるいは送電アンテナと受電アンテナとの距離が大きくなることが挙げられる。送電アンテナと受電アンテナとの間に異物が入ると、異物に熱が発生する可能性がある。 Factors that can cause the coupling coefficient to decrease include the presence of a foreign object (such as a metal piece) between the power transmitting antenna and the power receiving antenna, or a misalignment between the power transmitting antenna and the power receiving antenna. Alternatively, the distance between the power transmitting antenna and the power receiving antenna may increase. If a foreign object is placed between the power transmitting antenna and the power receiving antenna, heat may be generated in the foreign object.
　また、送電アンテナと受電アンテナとの位置ずれや離間が発生すると漏れ磁束（漏洩磁束）が多くなるので、周囲に大きなノイズを発生させる可能性がある。ｋ値が小さい場合には、より安全で高品質な無線電力伝送を実現するための適切な制御が必要である。本実施形態では、異物の検出精度や前記位置ずれや前記距離が大きい場合の検出精度を向上させるために、送電アンテナと受電アンテナとの結合状態（結合係数を含む）を検出する処理が行われる。 Furthermore, if there is a misalignment or separation between the power transmitting antenna and the power receiving antenna, there will be a lot of leakage magnetic flux, which may cause a lot of noise in the surrounding area. When the k value is small, appropriate control is required to achieve safer and higher quality wireless power transmission. In this embodiment, a process is performed to detect the coupling state (including the coupling coefficient) between the power transmitting antenna and the power receiving antenna in order to improve the detection accuracy of foreign objects and the detection accuracy when the misalignment or distance is large.
　図１１（Ａ）、（Ｂ）を参照して、送電アンテナと受電アンテナの結合状態指標測定法について説明する。図１１（Ａ）は、第１の測定方法を説明するための等価回路図である。１次側（ＴＸ）の送電アンテナ（送電コイル）に関する諸量の定義を下記に示す。
・ｒ１：送電アンテナの巻き線抵抗。
・Ｌ１：送電アンテナの自己インダクタンス。
・Ｖ１：ＴＸが測定した、送電アンテナにかかる送電電圧（入力電圧）。 A method for measuring the coupling state indicator of the power transmitting antenna and the power receiving antenna will be described with reference to Fig. 11 (A) and (B). Fig. 11 (A) is an equivalent circuit diagram for explaining the first measurement method. The definitions of various quantities related to the power transmitting antenna (power transmitting coil) on the primary side (TX) are shown below.
r1: Winding resistance of the transmitting antenna.
L1: Self-inductance of the transmitting antenna.
V1: The transmitting voltage (input voltage) across the transmitting antenna, measured by the TX.
　また、２次側（ＲＸ）の受電アンテナ（受電コイル）に関する諸量の定義を下記に示す。
・ｒ２：受電アンテナの巻き線抵抗。
・Ｌ２：受電アンテナの自己インダクタンス。
・Ｖ２：ＲＸが測定した、受電アンテナにかかる受電電圧（出力電圧）。 The following are definitions of various quantities related to the receiving antenna (receiving coil) on the secondary side (RX).
r2: Winding resistance of the receiving antenna.
L2: Self-inductance of the receiving antenna.
V2: The receiving voltage (output voltage) across the receiving antenna measured by the RX.
　送電アンテナと受電アンテナとの結合係数ｋは、下記式２により算出できる。
　ｋ＝（Ｖ２／Ｖ１）・√（Ｌ１／Ｌ２）　　　（式２） The coupling coefficient k between the power transmitting antenna and the power receiving antenna can be calculated by the following formula 2.
k = (V2/V1) · √(L1/L2) (Equation 2)
　ＴＸが結合係数ｋを算出する場合、ＲＸは測定した受電電圧Ｖ２と、予めＲＸが保持している受電アンテナの自己インダクタンスＬ２の値をＴＸに通知する。ＴＸは測定した送電電圧Ｖ１と、予め保持している送電アンテナの自己インダクタンスＬ１の値と、ＲＸから受信した受電電圧Ｖ２と自己インダクタンスＬ２の値を用いてｋ値を算出する。 When the TX calculates the coupling coefficient k, the RX notifies the TX of the measured receiving voltage V2 and the value of the self-inductance L2 of the receiving antenna that the RX holds in advance. The TX calculates the k value using the measured transmitting voltage V1, the value of the self-inductance L1 of the transmitting antenna that the TX holds in advance, and the receiving voltage V2 and self-inductance L2 values received from the RX.
　あるいは、ＲＸはＬ１，Ｌ２のすべて、またはいずれかを用いて算出される定数と、Ｖ２をＴＸに通知し、ＴＸはＲＸから受信した当該定数とＶ２と、ＴＸが測定した送電電圧Ｖ１とを用いてｋ値を算出することができる。 Alternatively, RX can notify TX of a constant calculated using either or both of L1 and L2, and V2, and TX can calculate the k value using the constant and V2 received from RX, and the transmission voltage V1 measured by TX.
　一方、ＲＸが結合係数ｋを算出する場合、ＴＸは測定した送電電圧Ｖ１と、予め保持している送電アンテナの自己インダクタンスＬ１の値をＲＸに通知する。ＲＸは測定した受電電圧Ｖ２と、予め保持している受電アンテナの自己インダクタンスＬ２の値と、ＴＸから受信した送電電圧Ｖ１と自己インダクタンスＬ１の値を用いてｋ値を算出する。 On the other hand, when the RX calculates the coupling coefficient k, the TX notifies the RX of the measured transmission voltage V1 and the previously stored value of the self-inductance L1 of the transmission antenna. The RX calculates the k value using the measured receiving voltage V2, the previously stored value of the self-inductance L2 of the receiving antenna, and the values of the transmission voltage V1 and self-inductance L1 received from the TX.
　あるいは、ＴＸはＬ１，Ｌ２のすべて、またはいずれかを用いて算出される定数と、Ｖ１をＲＸに通知し、ＲＸはＴＸから受信した当該定数とＶ１と、ＲＸが測定した受電電圧Ｖ２とを用いてｋ値を算出することができる。 Alternatively, the TX can notify the RX of a constant calculated using either or both of L1 and L2, and V1, and the RX can calculate the k value using the constant and V1 received from the TX, and the receiving voltage V2 measured by the RX.
　送電電圧Ｖ１については、ＴＸが送電アンテナにかかる電圧を実際に測定するか、またはＴＸが送電電力の設定値から算出する。あるいは送電電圧Ｖ１を送電時の送電電圧の設定値としてもよい。また、ＴＸの送電部１０３が有する回路（例えばインバータ）にかかる送電電圧（Ｖ３と記す）と、共振コンデンサ１０７の両端にかかる電圧から送電アンテナにかかる送電電圧Ｖ１を求めることができる。 The transmission voltage V1 is calculated by the TX actually measuring the voltage applied to the transmission antenna, or by the TX calculating it from the set value of the transmission power. Alternatively, the transmission voltage V1 may be set as the set value of the transmission voltage during transmission. In addition, the transmission voltage V1 applied to the transmission antenna can be calculated from the transmission voltage (denoted as V3) applied to a circuit (e.g., an inverter) in the TX's transmission unit 103 and the voltage across the resonant capacitor 107.
　この場合、送電電圧Ｖ３についてもＴＸが送電電力の設定値から算出してもよい。あるいは、ＴＸが、送電電圧Ｖ３と共振コンデンサ１０７の両端にかかる電圧を実際に測定して、それらを用いて送電電圧Ｖ１を求めてもよい。 In this case, the TX may also calculate the transmission voltage V3 from the set value of the transmission power. Alternatively, the TX may actually measure the transmission voltage V3 and the voltage across the resonant capacitor 107, and use these to determine the transmission voltage V1.
　また、ＴＸまたはＲＸが第１の測定方法を実施する際、ＲＸは第２スイッチ部２１０をＯＦＦにして、受電アンテナ２０５の端子が開放状態になるように制御してもよい。これにより、図１１（Ａ）で示すように受電アンテナの両端を開放状態にすることが可能となる。第１の測定方法にて共振コンデンサ２１１、受電部２０３、充電部２０６、バッテリ２０７による影響を受けることが無いので、より高精度に結合係数ｋの測定が可能となる。 Also, when the TX or RX performs the first measurement method, the RX may control the second switch unit 210 to be turned OFF so that the terminals of the power receiving antenna 205 are in an open state. This makes it possible to put both ends of the power receiving antenna in an open state as shown in FIG. 11(A). Since the first measurement method is not affected by the resonant capacitor 211, the power receiving unit 203, the charging unit 206, and the battery 207, it becomes possible to measure the coupling coefficient k with higher accuracy.
　また、ＲＸの受電部２０３が有する回路（例えば整流器）にかかる受電電圧（Ｖ４と記す）と、共振コンデンサ２１１の両端にかかる電圧から受電アンテナにかかる受電電圧Ｖ２を求めることができる。 In addition, the receiving voltage V2 applied to the receiving antenna can be calculated from the receiving voltage (denoted as V4) applied to a circuit (e.g., a rectifier) in the RX receiving unit 203 and the voltage across the resonant capacitor 211.
　この場合、ＲＸが、受電電圧Ｖ４と共振コンデンサ２１１の両端にかかる電圧を実際に測定して、それらを用いて受電電圧Ｖ２を求めてもよい。あるいは、ＲＸは、測定した受電電圧Ｖ４と共振コンデンサ２１１の両端にかかる電圧の値をＴＸに送信し、ＴＸが受電電圧Ｖ２を求めることで、ｋ値を算出してもよい。 In this case, the RX may actually measure the receiving voltage V4 and the voltage across the resonant capacitor 211, and use these to determine the receiving voltage V2. Alternatively, the RX may transmit the measured values of the receiving voltage V4 and the voltage across the resonant capacitor 211 to the TX, and the TX may determine the receiving voltage V2, thereby calculating the k value.
　あるいは、ＴＸまたはＲＸが第１の測定方法を実施する際、ＲＸは軽負荷状態または負荷接続状態となるように制御してもよい。ＲＸの負荷の状態を一定にすることで、より高精度に結合係数ｋの測定が可能となる。 Alternatively, when the TX or RX performs the first measurement method, the RX may be controlled to be in a light load state or in a load-connected state. By keeping the load state of the RX constant, it becomes possible to measure the coupling coefficient k with higher accuracy.
　送電アンテナと受電アンテナとの電磁結合状態を表す指標としては、結合係数以外にも複数の量があり、本実施形態では、それらを総称して「結合状態指標」と呼ぶ。結合状態指標はいずれも、送電アンテナと受電アンテナとの電磁結合状態に対応する値を有する。結合係数以外の、その他の結合状態指標を用いる場合にも同様に本実施形態の内容を適用可能である。 In addition to the coupling coefficient, there are several other quantities that can be used as indices to represent the electromagnetic coupling state between the transmitting antenna and the receiving antenna. In this embodiment, these are collectively referred to as "coupling state indices." Each coupling state indices has a value that corresponds to the electromagnetic coupling state between the transmitting antenna and the receiving antenna. The contents of this embodiment can also be applied in the same way when other coupling state indices than the coupling coefficient are used.
　例えば、結合状態指標として、ＴＸの送電部１０３が有する回路（例えばインバータ）にかかる送電電圧Ｖ３と、ＲＸの受電部２０３が有する回路（例えば整流器）にかかる受電電圧（Ｖ４と記す）がある。これらを用いて送電アンテナと受電アンテナとの結合状態の算出処理を行うことができる。 For example, the coupling state indicators include the transmission voltage V3 applied to a circuit (e.g., an inverter) of the power transmitting unit 103 of the TX, and the receiving voltage (denoted as V4) applied to a circuit (e.g., a rectifier) of the power receiving unit 203 of the RX. Using these, the coupling state between the transmitting antenna and the receiving antenna can be calculated.
　あるいはＲＸの受電部２０３が有する回路（例えば整流器）の出力電圧（Ｖ５と記す）を用いて送電アンテナと受電アンテナとの結合状態の算出が可能である。出力電圧Ｖ５は、負荷（充電部、バッテリ）に印加される電圧である。ＴＸは送電電圧Ｖ３をＲＸに通知し、ＲＸは結合状態指標を算出することが可能となる。 Alternatively, the coupling state between the transmitting antenna and the receiving antenna can be calculated using the output voltage (denoted as V5) of a circuit (e.g., a rectifier) in the receiving unit 203 of the RX. The output voltage V5 is the voltage applied to the load (charging unit, battery). The TX notifies the RX of the transmitting voltage V3, and the RX can calculate the coupling state index.
　このとき、ＴＸは送電アンテナの電気特性（例えばＬ１）を用いて算出される定数をＲＸに通知し、ＲＸは当該定数を用いて結合状態指標を算出することができる。つまり、ＲＸは、ＴＸから受信した送電電圧Ｖ３と、ＴＸから受信した送電アンテナの電気特性（例えばＬ１）を用いて算出される定数と、ＲＸが測定した受電電圧Ｖ４または出力電圧Ｖ５から結合状態指標を算出することができる。 At this time, the TX notifies the RX of a constant calculated using the electrical characteristics of the transmitting antenna (e.g., L1), and the RX can calculate the coupling state index using the constant. In other words, the RX can calculate the coupling state index from the transmitting voltage V3 received from the TX, a constant calculated using the electrical characteristics of the transmitting antenna received from the TX (e.g., L1), and the receiving voltage V4 or output voltage V5 measured by the RX.
　あるいは、ＲＸは受電電圧Ｖ４または出力電圧Ｖ５をＴＸに通知し、ＴＸは結合状態指標を算出する。このとき、ＲＸは受電アンテナの電気特性（例えばＬ２）を用いて算出される定数をＴＸに通知し、ＴＸは当該定数を用いて結合状態指標を算出することができる。つまり、ＴＸは、ＲＸから受信した受電電圧Ｖ４または出力電圧Ｖ５と、ＲＸから受信した受電アンテナの電気特性（例えばＬ２）を用いて算出される定数と、ＴＸが測定した送電電圧Ｖ３から結合状態指標を算出することができる。 Alternatively, the RX notifies the TX of the receiving voltage V4 or the output voltage V5, and the TX calculates the coupling state index. At this time, the RX notifies the TX of a constant calculated using the electrical characteristics of the receiving antenna (e.g., L2), and the TX can calculate the coupling state index using the constant. In other words, the TX can calculate the coupling state index from the receiving voltage V4 or the output voltage V5 received from the RX, a constant calculated using the electrical characteristics of the receiving antenna received from the RX (e.g., L2), and the transmitting voltage V3 measured by the TX.
　ＴＸとＲＸは、Ｖ１からＶ５の電圧値、自己インダクタンスＬ１，Ｌ２の値、あるいは送電アンテナや受電アンテナの電気特性を表す定数の情報を送受し合う。以下、電圧値の測定のタイミングと、各情報の送受のタイミングについて説明する。各電圧値の測定は、例えばＰｉｎｇ　Ｐｈａｓｅに実行される。 TX and RX exchange information such as the voltage values V1 to V5, the self-inductance values L1 and L2, or constants that represent the electrical characteristics of the transmitting and receiving antennas. The timing of measuring the voltage values and the timing of sending and receiving each piece of information are explained below. Measurement of each voltage value is performed, for example, in the Ping Phase.
　Ｐｉｎｇ　Ｐｈａｓｅでは、ＴＸはＲＸに対してＤＰを送信する。よって、ＤＰの送信時に発生するＶ１，Ｖ２，Ｖ３，Ｖ４，Ｖ５のいずれかの電圧値を用いることができる。Ｐｉｎｇ　ＰｈａｓｅにてＴＸおよびＲＸは、Ｖ１からＶ５のいずれかの値を測定してメモリ１０６またはメモリ２０８に記憶保持する。 In the Ping Phase, the TX transmits a DP to the RX. Therefore, any of the voltage values V1, V2, V3, V4, and V5 that are generated when transmitting a DP can be used. In the Ping Phase, the TX and RX measure any of the values V1 to V5 and store and hold the value in memory 106 or memory 208.
　ＴＸは、ＲＸから通知されたＶ２、Ｖ４、Ｖ５のいずれかの電圧値の情報を有する所定パケットを受信し、当該情報をメモリ１０６に記憶する。所定パケットが有する情報には、ＲＸの受電電圧だけでなく、受電電力や自己インダクタンスＬ２の値、受電アンテナの電気特性を用いて算出される定数等の情報が含まれてもよい。 The TX receives a predetermined packet containing information on the voltage value of V2, V4, or V5 notified by the RX, and stores the information in memory 106. The information contained in the predetermined packet may include not only the receiving voltage of the RX, but also the receiving power, the value of the self-inductance L2, a constant calculated using the electrical characteristics of the receiving antenna, and other information.
　所定パケットとしては、Ｓｉｇｎａｌ　Ｓｔｒｅｎｇｔｈ　Ｄａｔａ　ｐａｃｋｅｔを使用して、ＲＸの情報をＴＸに通知することができる。あるいは所定パケットは、Ｉ＆Ｃ　Ｐｈａｓｅにおける、Ｉｄｅｎｔｉｆｉｃａｔｉｏｎ　Ｄａｔａ　ｐａｃｋｅｔまたはＥｘｔｅｎｄｅｄ　Ｉｄｅｎｔｉｆｉｃａｔｉｏｎ　Ｄａｔａ　ｐａｃｋｅｔであってもよい。 As the specified packet, a Signal Strength Data packet can be used to notify RX information to TX. Alternatively, the specified packet may be an Identification Data packet or an Extended Identification Data packet in the I&C Phase.
　またはＣｏｎｆｉｇｕｒａｔｉｏｎ　Ｄａｔａ　ｐａｃｋｅｔであってもよい。あるいは、Ｃａｌｉｂｒａｔｉｏｎ　ＰｈａｓｅやＰｏｗｅｒ　Ｔｒａｎｓｆｅｒ　ＰｈａｓｅにおけるＰａｃｋｅｔであってもよい。つまりＲＰ１、ＲＰ２、ＲＰ０でもよい。なお、ＴＸがＤＰの送信時に発生する電圧値を用いる例に限定されることはない。Ｓｅｌｅｃｔｉｏｎ　ＰｈａｓｅにてＴＸがＡＰを送信する時に発生するＶ１からＶ５のいずれかの電圧値を用いてもよい。 Or it may be a Configuration Data packet. Or it may be a packet in the Calibration Phase or Power Transfer Phase. In other words, it may be RP1, RP2, or RP0. Note that this is not limited to the example in which the voltage value generated when the TX transmits a DP is used. Any of the voltage values V1 to V5 generated when the TX transmits an AP in the Selection Phase may be used.
　ＲＸは第１の測定方法を実施する際、共振コンデンサ２１１と受電部２０３との間に設けられるスイッチ部（不図示）をＯＦＦにして受電アンテナ２０５と共振コンデンサ２１１で構成される回路の端子が開放状態になるように制御してもよい。これにより、第１の測定方法の実施において受電部２０３、充電部２０６、バッテリ２０７による影響を受けることがないので、より高精度に結合状態指標の測定が可能となる。 When implementing the first measurement method, the RX may control the switch unit (not shown) provided between the resonant capacitor 211 and the power receiving unit 203 to be turned OFF so that the terminals of the circuit formed by the power receiving antenna 205 and the resonant capacitor 211 are in an open state. This allows the coupling state index to be measured with higher accuracy since the implementation of the first measurement method is not affected by the power receiving unit 203, the charging unit 206, or the battery 207.
　次に、送電アンテナと受電アンテナの結合状態指標測定法の別例として、第２の測定方法について説明する。図１１（Ｂ）は、第２の測定方法を説明するための等価回路図である。ｒ１，ｒ２とＬ１，Ｌ２については図１１（Ａ）と同じである。１次側（ＴＸ）の送電アンテナ（コイル）に関する諸量の定義を下記に示す。 Next, a second measurement method will be explained as another example of a method for measuring the coupling state indicator between the transmitting antenna and the receiving antenna. Figure 11(B) is an equivalent circuit diagram for explaining the second measurement method. r1, r2 and L1, L2 are the same as in Figure 11(A). The various quantities related to the transmitting antenna (coil) on the primary side (TX) are defined below.
・Ｖ６：受電アンテナ側がショート状態のときの送電アンテナの入力電圧。
・Ｖ７：受電アンテナ側がオープン状態のときの送電アンテナの入力電圧。
・Ｉ１：受電アンテナ側がショート状態のときの送電アンテナに流れる電流。
・Ｉ２：受電アンテナ側がオープン状態のときの送電アンテナに流れる電流。 V6: Input voltage of the transmitting antenna when the receiving antenna is shorted.
V7: Input voltage of the transmitting antenna when the receiving antenna is in an open state.
I1: The current flowing through the transmitting antenna when the receiving antenna is shorted.
I2: The current flowing through the transmitting antenna when the receiving antenna is in an open state.
　結合係数ｋは、下記式３により算出することができる。
　ｋ＝√（１－Ｌｓｃ／Ｌｏｐｅｎ）　　　（式３） The coupling coefficient k can be calculated by the following formula 3.
k = √(1-Lsc/Lopen) (Equation 3)
　式３中のＬｓｃは、受電アンテナの両端を短絡させた場合の、送電アンテナのインダンクタンスを表す。例えば制御部２０１は第２スイッチ部２１０をＯＮ状態（短絡状態）にする。この状態で送電アンテナのインダクタンス値を測定することでＬｓｃ値を取得できる。送電アンテナのインダクタンス値は、送電アンテナの入力電圧Ｖ６および電流Ｉ１から求めることができる。 Lsc in Equation 3 represents the inductance of the power transmitting antenna when both ends of the power receiving antenna are short-circuited. For example, the control unit 201 sets the second switch unit 210 to the ON state (short-circuit state). In this state, the Lsc value can be obtained by measuring the inductance value of the power transmitting antenna. The inductance value of the power transmitting antenna can be found from the input voltage V6 and current I1 of the power transmitting antenna.
　式３中のＬｏｐｅｎは、受電アンテナの両端を開放させた場合の、送電アンテナのインダンクタンスを表す。例えば制御部２０１は第２スイッチ部２１０をＯＦＦ状態（開放状態）にする。この状態で送電アンテナのインダクタンス値を測定することでＬｏｐｅｎ値を取得できる。 In Equation 3, Lopen represents the inductance of the power transmitting antenna when both ends of the power receiving antenna are open. For example, the control unit 201 sets the second switch unit 210 to the OFF state (open state). In this state, the Lopen value can be obtained by measuring the inductance value of the power transmitting antenna.
　送電アンテナのインダクタンス値は、送電アンテナの入力電圧Ｖ７および電流Ｉ２から求めることができる。第２の測定方法では、結合状態指標（結合係数）を、受電アンテナの両端を短絡にした場合と開放にした場合におけるそれぞれの、送電アンテナの入力電圧と電流から求めることが可能である。 The inductance value of the transmitting antenna can be determined from the input voltage V7 and current I2 of the transmitting antenna. In the second measurement method, the coupling state index (coupling coefficient) can be determined from the input voltage and current of the transmitting antenna when both ends of the receiving antenna are short-circuited and open.
　またＴＸは、送電部１０３が含む回路（例えばインバータ）にかかる送電電圧と電流に基づいて結合状態指標を算出することが可能である。この場合、入力電圧Ｖ６，Ｖ７は送電部１０３が含む回路（例えばインバータ）にかかる送電電圧を表す。また入力電圧Ｖ６，Ｖ７は送電アンテナと共振コンデンサから成る直列共振回路の両端子にかかる電圧であってもよい。 The TX can also calculate the coupling state index based on the transmission voltage and current applied to a circuit (e.g., an inverter) included in the power transmitting unit 103. In this case, the input voltages V6 and V7 represent the transmission voltage applied to a circuit (e.g., an inverter) included in the power transmitting unit 103. The input voltages V6 and V7 may also be the voltages applied to both terminals of a series resonant circuit consisting of a power transmitting antenna and a resonant capacitor.
　あるいは、送電部１０３が含む回路（例えばインバータ）にかかる送電電圧と、共振コンデンサ１０７の両端にかかる電圧を測定し、その結果から送電アンテナにかかる電圧を算出してもよい。つまり、送電部１０３が含む回路（例えばインバータ）にかかる送電電圧と、共振コンデンサ１０７の両端にかかる電圧の測定結果から、結合状態指標を求めることが可能である。この場合の送電部１０３が含む回路（例えばインバータ）にかかる送電電圧は、ＴＸが送電電力の設定値から算出してもよい。 Alternatively, the transmission voltage across a circuit (e.g., an inverter) included in the power transmitting unit 103 and the voltage across both ends of the resonant capacitor 107 may be measured, and the voltage across the power transmitting antenna may be calculated from the results. In other words, it is possible to obtain a coupling state index from the measurement results of the transmission voltage across a circuit (e.g., an inverter) included in the power transmitting unit 103 and the voltage across both ends of the resonant capacitor 107. In this case, the transmission voltage across a circuit (e.g., an inverter) included in the power transmitting unit 103 may be calculated by the TX from the set value of the transmission power.
　また、図１１（Ｂ）にて電流Ｉ１またはＩ２は送電アンテナに流れる電流に限定されず、例えば送電部１０３が含む回路（例えばインバータ）に流れる電流であってもよい。受電アンテナのオープン状態およびショート状態については、制御部２０１が第２スイッチ部２１０の制御により実現する例を説明した。これらの状態は受電部２０３で実現されてもよい。またショート状態に代えて、Ｌｉｇｈｔ　Ｌｏａｄ状態（軽負荷状態）としてもよい。 In addition, in FIG. 11(B), the current I1 or I2 is not limited to a current flowing through the power transmitting antenna, and may be, for example, a current flowing through a circuit (e.g., an inverter) included in the power transmitting unit 103. The open state and short state of the power receiving antenna have been described as being realized by the control unit 201 through control of the second switch unit 210. These states may also be realized by the power receiving unit 203. Also, instead of the short state, a light load state may be used.
　第２の測定方法にてＴＸは、入力電圧Ｖ６，Ｖ７および電流Ｉ１，Ｉ２を測定することによって結合状態指標の算出が可能である。よってＲＸが測定する電圧値や受電アンテナのインダクタンス値等の情報は必要ないので、ＲＸからＴＸに対する当該情報の通知は不要である。 In the second measurement method, the TX can calculate the coupling state index by measuring the input voltages V6 and V7 and the currents I1 and I2. Therefore, information such as the voltage value measured by the RX or the inductance value of the receiving antenna is not required, so there is no need for the RX to notify the TX of this information.
　ただし、ＴＸが入力電圧Ｖ６および電流Ｉ１を測定するときに、ＲＸは受電アンテナが含まれる回路の両端子をＳＨＯＲＴ（短絡）にする必要がある。また、ＴＸが入力電圧Ｖ７および電流Ｉ２を測定するときに、ＲＸは受電アンテナが含まれる回路の両端子をＯＰＥＮ（開放）にする必要がある。 However, when the TX measures the input voltage V6 and the current I1, the RX needs to keep both terminals of the circuit that includes the receiving antenna in SHORT. Also, when the TX measures the input voltage V7 and the current I2, the RX needs to keep both terminals of the circuit that includes the receiving antenna in OPEN.
　つまり、ＴＸが入力電圧および電流を測定するタイミングに応じて、ＲＸは受電アンテナが含まれる回路の両端子をＳＨＯＲＴ（短絡）またはＯＰＥＮ（開放）の状態に制御することが必要である。測定のタイミングについては、ＴＸが決定してＲＸに通知するか、または、ＲＸが決定してＴＸに通知する。この通知は、ＴＸの通信部１０４とＲＸの通信部２０４とが行う通信によって実施される。 In other words, depending on the timing at which the TX measures the input voltage and current, the RX needs to control both terminals of the circuit containing the receiving antenna to a SHORT or OPEN state. The TX decides on the measurement timing and notifies the RX, or the RX decides on the measurement timing and notifies the TX. This notification is performed by communication between the communication unit 104 of the TX and the communication unit 204 of the RX.
　入力電圧Ｖ６，Ｖ７および電流Ｉ１，Ｉ２の測定は、例えばＰｉｎｇ　Ｐｈａｓｅに実行される。Ｐｉｎｇ　Ｐｈａｓｅでは、ＴＸはＲＸに対してＤＰを送信する。よって、ＤＰの送信時に発生するＶ６，Ｖ７や電流Ｉ１，Ｉ２の値を用いることができる。 The input voltages V6, V7 and currents I1, I2 are measured, for example, in the Ping Phase. In the Ping Phase, the TX transmits a DP to the RX. Therefore, the values of V6, V7 and currents I1, I2 generated when the DP is transmitted can be used.
　Ｐｉｎｇ　Ｐｈａｓｅにおいて、ＴＸはＶ６，Ｖ７，Ｉ１，Ｉ２の値を取得してメモリ１０６に保持し、結合状態指標を算出する。なお、ＴＸがＤＰの送信時に発生する前記電圧値、電流値を用いる例に限定されることはない。例えばＳｅｌｅｃｔｉｏｎ　ＰｈａｓｅにてＴＸがＡＰの送信時に発生するＶ６，Ｖ７，Ｉ１，Ｉ２の値を用いてもよい。 In the Ping Phase, the TX acquires the values of V6, V7, I1, and I2, stores them in the memory 106, and calculates the binding state index. Note that the TX is not limited to using the voltage and current values generated when transmitting a DP. For example, the TX may use the values of V6, V7, I1, and I2 generated when transmitting an AP in the Selection Phase.
　本開示では、送電アンテナと受電アンテナの結合状態指標測定法に関し、第１の測定方法および第２の測定方法のいずれも適用可能であるものとする。第１または第２の測定方法により取得される結合状態指標に対する状態判定用閾値が設定される。 In this disclosure, both the first and second measurement methods are applicable to the method of measuring the coupling status index of the transmitting antenna and the receiving antenna. A status determination threshold is set for the coupling status index obtained by the first or second measurement method.
　状態判定とは、送電アンテナと受電アンテナとの間の異物検出に関する判定や、送電アンテナと受電アンテナとの位置ずれの検出に関する判定や、送電アンテナと受電アンテナとが離れていることの検出に関する判定等である。第１または第２の測定方法を実施して、状態判定用閾値を用いて状態異常の有無（または可能性）を判定することが可能である。 The status determination includes a determination regarding the detection of a foreign object between the power transmitting antenna and the power receiving antenna, a determination regarding the detection of a misalignment between the power transmitting antenna and the power receiving antenna, a determination regarding the detection of the separation between the power transmitting antenna and the power receiving antenna, etc. By implementing the first or second measurement method, it is possible to determine the presence (or possibility) of a status abnormality using a status determination threshold value.
　図１２と図１３を参照して、受電装置４０１および送電装置４０２が実行する処理について説明する。図１２は、送電中の波形減衰法による異物検出を実行する際、送電装置４０２（ＴＸ）の処理を説明するフローチャートであり、図１３は受電装置４０１（ＲＸ）の処理を説明するフローチャートである。Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにて、波形減衰法による異物検出処理の例を示す。 The processing executed by the power receiving device 401 and the power transmitting device 402 will be described with reference to Figs. 12 and 13. Fig. 12 is a flowchart explaining the processing of the power transmitting device 402 (TX) when performing foreign object detection using the waveform attenuation method during power transmission, and Fig. 13 is a flowchart explaining the processing of the power receiving device 401 (RX). An example of foreign object detection processing using the waveform attenuation method in the Power Transfer Phase is shown.
　図１２のＳ１２０１でＴＸはＲＸに対して送電コイルグループでの送電を開始する。送電制御部３０２は複数のスイッチ部１０８を制御することで、選択された送電コイルを用いて送電を行う。例えば、図７の送電コイルグループ１１０１での送電が開始され、送電制御部３０２は所定の送電コイルに対応するスイッチ部１０８を有効（ＯＮ）に設定する。 In S1201 in FIG. 12, TX starts transmitting power to RX using the power transmission coil group. The power transmission control unit 302 controls multiple switch units 108 to transmit power using a selected power transmission coil. For example, power transmission is started in the power transmission coil group 1101 in FIG. 7, and the power transmission control unit 302 sets the switch unit 108 corresponding to a specific power transmission coil to enabled (ON).
　Ｓ１２０２でＴＸは、送電期間中にＲＸからのメッセージを受信したか否かを判定する。通信制御部３０１は通信部１０４の受信情報を確認する。ＲＸからのメッセージの受信が確認された場合、ＴＸは受信したメッセージの情報をメモリ１０６に保存し、Ｓ１２０３の処理に進む。また、ＲＸからのメッセージの受信が確認されない場合、ＴＸはＳ１２０２の判定処理を繰り返し実行する。 In S1202, the TX judges whether or not a message has been received from the RX during the power transmission period. The communication control unit 301 checks the reception information of the communication unit 104. If reception of a message from the RX is confirmed, the TX stores the information of the received message in the memory 106 and proceeds to the processing of S1203. If reception of a message from the RX is not confirmed, the TX repeatedly executes the judgment processing of S1202.
　Ｓ１２０３でＴＸは、ＲＸから受信したメッセージが異物検出実行要求のメッセージであるか否かを判定する。制御部１０１はメモリ１０６上のメッセージの情報を確認し、その種別を判断する。異物検出実行要求のメッセージとしては、ＷＰＣ規格のＲｅｃｅｉｖｅｄ　Ｐｏｗｅｒ　Ｄａｔａ　Ｐａｃｋｅｔ（ＲＰパケット）を用いることができる。 In S1203, TX determines whether the message received from RX is a message requesting execution of foreign object detection. The control unit 101 checks the message information in memory 106 and determines the type of the message. The message requesting execution of foreign object detection can be a Received Power Data Packet (RP packet) of the WPC standard.
　ＲＰパケットには、波形減衰法による異物検出のための送電停止時間の情報が含まれている。Ｓ１２０３で異物検出実行要求のメッセージが受信されたことが判断された場合、Ｓ１２０４の処理に進んで波形減衰法による異物検出を開始する。Ｓ１２０３で異物検出実行要求のメッセージではないと判断された場合、Ｓ１２１０の処理に移行する。 The RP packet contains information about the power transmission stop time for foreign object detection using the waveform attenuation method. If it is determined in S1203 that a message requesting execution of foreign object detection has been received, the process proceeds to S1204 and foreign object detection using the waveform attenuation method is started. If it is determined in S1203 that the message is not a message requesting execution of foreign object detection, the process proceeds to S1210.
　Ｓ１２０４でＴＸは、受信した異物検出実行要求に含まれる送電停止時間の情報に基づき、送電コイルグループ１１０１の各送電コイルに対して送電停止時間を設定する。送電制御部３０２は、送電コイルグループ１１０１を構成する各送電コイル（送電アンテナ）と送電停止時間との関連付けを行う。 In S1204, the TX sets a power transmission stop time for each power transmission coil of the power transmission coil group 1101 based on the information on the power transmission stop time included in the received request to execute foreign object detection. The power transmission control unit 302 associates each power transmission coil (power transmission antenna) constituting the power transmission coil group 1101 with the power transmission stop time.
　Ｓ１２０５でＴＸは、送電コイルグループ１１０１の各送電コイルに設定された時間で送電を停止する制御を行う。送電制御部３０２は送電コイル（送電アンテナ）のスイッチ部１０８を制御することで、複数の送電コイルによる送電を、設定された送電停止時間で同時に停止させることができる。次にＳ１２０６の処理に進む。 In S1205, the TX performs control to stop power transmission at the time set for each power transmission coil in the power transmission coil group 1101. The power transmission control unit 302 controls the switch unit 108 of the power transmission coil (power transmission antenna) to simultaneously stop power transmission by the multiple power transmission coils at the set power transmission stop time. Next, the process proceeds to S1206.
　Ｓ１２０６でＴＸは、送電停止による波形（図８）の減衰の推移を測定し、波形減衰指標として、例えばＱ値を取得する処理を行う。測定部３０３が波形の減衰の測定を行うことで各送電コイルに係るＱ値の取得が可能である。つまり、送電停止が実行された、すべての送電コイルに対してＱ値が取得される。 In S1206, the TX measures the attenuation of the waveform (FIG. 8) due to the power transmission being stopped, and performs processing to obtain, for example, the Q value as an index of waveform attenuation. The measurement unit 303 measures the attenuation of the waveform, making it possible to obtain the Q value for each power transmission coil. In other words, the Q value is obtained for all power transmission coils for which power transmission has been stopped.
　次にＳ１２０７でＴＸは、各送電コイルに係るＱ値の測定値と、閾値（基準のＱ値）とを比較する。基準のＱ値は、例えば図６のＦ５０６で取得されたＱ値である。異物検出部３０５は基準のＱ値と、Ｓ１２０６で取得されたＱ値の測定値とを比較して異物検出を行う。送電コイルグループ１１０１を構成する各送電コイルに対し、送電コイルの数だけ異物検出結果が取得される。次にＳ１２０８の処理に進む。 Next, in S1207, the TX compares the measured Q value for each transmitting coil with a threshold value (reference Q value). The reference Q value is, for example, the Q value acquired in F506 in FIG. 6. The foreign object detection unit 305 compares the reference Q value with the measured Q value acquired in S1206 to detect a foreign object. For each transmitting coil constituting the transmitting coil group 1101, foreign object detection results are acquired for each transmitting coil. Next, the process proceeds to S1208.
　Ｓ１２０８では、Ｓ１２０７で取得された複数の異物検出結果に対し、多数決原理に基づいて最終的な異物検出結果を確定する処理が行われる。異物検出部３０５は、複数の異物検出結果を解析し、最多数の異物検出結果を最終的な異物検出結果として判定する。 In S1208, a process is performed to determine the final foreign object detection result based on the majority rule for the multiple foreign object detection results obtained in S1207. The foreign object detection unit 305 analyzes the multiple foreign object detection results and determines the foreign object detection result with the greatest number as the final foreign object detection result.
　次にＳ１２０９でＴＸは、異物検出実行要求に対する応答として、異物検出結果の取得を依頼するメッセージ（以下、依頼メッセージという）をＲＸに送信する。通信制御部３０１が通信部１０４に依頼メッセージを書き込むことでＲＸに依頼メッセージを送信することができる。依頼メッセージとしては、上記ＲＰパケットに対する応答として「ＡＴＮ」を用いることができる。Ｓ１２０９の後、Ｓ１２０２の処理に移行する。 Next, in S1209, TX sends a message (hereinafter, "request message") to RX requesting to obtain the foreign object detection result as a response to the request to execute foreign object detection. The request message can be sent to RX by the communication control unit 301 writing the request message to the communication unit 104. As the request message, "ATN" can be used as a response to the above RP packet. After S1209, the process proceeds to S1202.
　Ｓ１２０３からＳ１２１０の処理に進む場合、Ｓ１２１０でＴＸは、ＲＸから異物検出結果の取得を要求するメッセージ（以下、取得要求メッセージという）を受信したか否かを判断する。制御部１０１はメモリ１０６内のメッセージを確認することで、その種別を判断できる。 When the process proceeds from S1203 to S1210, in S1210, the TX determines whether or not it has received a message from the RX requesting to obtain the foreign object detection result (hereinafter, referred to as an acquisition request message). The control unit 101 can determine the type of message by checking the message in the memory 106.
　異物検出結果の取得要求メッセージとしては、ＷＰＣ規格のＤａｔａ　Ｓｔｒｅａｍ　Ｒｅｓｐｏｎｓｅを用いることができる。Ｓ１２１０で取得要求メッセージが受信されたことが判断された場合、Ｓ１２１１の処理に進み、取得要求メッセージが受信されていないと判断された場合にはＳ１２０２の処理に移行する。 The data stream response of the WPC standard can be used as the message requesting acquisition of the foreign object detection result. If it is determined in S1210 that the acquisition request message has been received, the process proceeds to S1211, and if it is determined that the acquisition request message has not been received, the process proceeds to S1202.
　Ｓ１２１１でＴＸは、Ｓ１２０８で確定した異物検出結果をＲＸに送信する。通信制御部３０１は異物検出部３０５が保持している異物検出結果を通知するメッセージを生成し、通信部１０４に書き込むことでＲＸにメッセージを送信することができる。 In S1211, TX transmits the foreign object detection result determined in S1208 to RX. The communication control unit 301 generates a message notifying the foreign object detection result held by the foreign object detection unit 305, and writes the message to the communication unit 104, thereby enabling the message to be transmitted to RX.
　異物検出結果を通知するメッセージには、ＷＰＣ規格のＦＯＤ　Ｓｔａｔｕｓ　Ｄａｔａ　Ｐａｃｋｅｔを用いることができる。Ｓ１２１１の後、Ｓ１２０２の処理に移行する。図１２に示す処理はＰｏｗｅｒ　Ｔｒａｎｓｆｅｒ　ＰｈａｓｅにてＲＸが異物検出の実行要求のメッセージをＴＸに送信するたびに繰り返し実行される処理を含む。 The message notifying the foreign object detection result can use the FOD Status Data Packet of the WPC standard. After S1211, the process proceeds to S1202. The process shown in FIG. 12 includes a process that is repeatedly executed every time the RX transmits a message requesting the execution of foreign object detection to the TX in the Power Transfer Phase.
　図１３を参照して、ＲＸの処理について説明する。以下の処理はＰｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにて所定のタイミングで繰り返し実行される。Ｓ１３０１にてＰｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅに移行すると、Ｓ１３０２でＲＸは受電を開始する。受電部２０３は受電アンテナ２０５による電力を受電し、充電部２０６に供給することでバッテリ２０７の充電が可能になる。 The RX process will be described with reference to FIG. 13. The following process is repeatedly executed at a predetermined timing in the Power Transfer Phase. When the process moves to the Power Transfer Phase in S1301, the RX starts receiving power in S1302. The power receiving unit 203 receives power from the power receiving antenna 205 and supplies it to the charging unit 206, thereby enabling charging of the battery 207.
　Ｓ１３０３でＲＸは、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにて異物検出実行要求のメッセージを送信するタイミングであるか否かを判定する。制御部２０１はタイマ等により、当該メッセージの送信のタイミングを決定することができる。異物検出実行要求のメッセージを送信するタイミングであると判定された場合、Ｓ１３０４の処理に進み、当該メッセージを送信するタイミングではない判定された場合にはＳ１３０３の判定処理が繰り返し実行される。 In S1303, RX determines whether or not it is time to send a message requesting execution of foreign object detection in the Power Transfer Phase. The control unit 201 can determine the timing of sending the message using a timer or the like. If it is determined that it is time to send a message requesting execution of foreign object detection, the process proceeds to S1304, and if it is determined that it is not time to send the message, the determination process of S1303 is repeated.
　Ｓ１３０４でＲＸは、異物検出実行要求のメッセージを生成してＴＸに送信する。例えば、制御部２０１はＲＰパケットに含める上記送電停止時間を決定し、通信部２０４に送電停止時間を含むＲＰパケットを書き込むことにより送信処理を行う。 In S1304, the RX generates a message requesting execution of foreign object detection and transmits it to the TX. For example, the control unit 201 determines the power transmission stop time to be included in the RP packet, and performs the transmission process by writing the RP packet including the power transmission stop time to the communication unit 204.
　この処理の後、図１２のＳ１２０３以降の処理が行われる。次にＳ１３０５でＲＸは、異物検出実行要求に対するＴＸからの応答を受信したか否かを判定する。これは制御部２０１が通信部２０４を監視することで実現可能である。当該応答が受信されない場合、所定時間の待機後にＳ１３０５の判定処理が繰り返し実行される。また当該応答が受信されたことが判定された場合、Ｓ１３０６の処理に進む。 After this process, the processes from S1203 onwards in FIG. 12 are carried out. Next, in S1305, RX judges whether or not a response to the request to execute foreign object detection has been received from TX. This can be achieved by the control unit 201 monitoring the communication unit 204. If the response is not received, the judgment process of S1305 is repeated after waiting for a predetermined time. If it is determined that the response has been received, the process proceeds to S1306.
　Ｓ１３０６でＲＸは、ＴＸから上記依頼メッセージ（ＲＰパケットレスポンスの「ＡＴＮ」）を受信したか否かを判定する。依頼メッセージが受信されたことが判定された場合、Ｓ１３０７の処理に進み、依頼メッセージが受信されないと判定された場合にはＳ１３１１の処理に移行する。 In S1306, RX determines whether or not the above request message (the "ATN" in the RP packet response) has been received from TX. If it is determined that the request message has been received, it proceeds to S1307, and if it is determined that the request message has not been received, it proceeds to S1311.
　Ｓ１３０７でＲＸはＴＸに対し、異物検出結果の取得要求メッセージ（Ｄａｔａ　Ｓｔｒｅａｍ　Ｒｅｓｐｏｎｓｅ）を送信する。制御部２０１は通信部２０４が受信したメッセージを確認した後、通信部２０４に取得要求メッセージを書き込むことで送信処理を行う。 In S1307, RX transmits a request message (Data Stream Response) for the foreign object detection result to TX. After confirming the message received by communication unit 204, control unit 201 performs transmission processing by writing the request message to communication unit 204.
　この処理により図１２のＳ１２１０の処理が開始される。Ｓ１３０８でＲＸは、Ｓ１３０５と同様に、ＴＸからの応答を受信したか否かを判定する。図１２のＳ１２１１における異物検出結果の通知メッセージが送信されるまで待機処理が実行される。ＴＸからの応答が受信されない場合、Ｓ１３０８の判定処理が繰り返し実行される。また、ＴＸからの応答が受信されたと判定された場合、Ｓ１３０９の処理に進む。 This process starts the process of S1210 in FIG. 12. In S1308, RX determines whether or not a response has been received from TX, similar to S1305. Waiting process is executed until a notification message of the foreign object detection result is sent in S1211 in FIG. 12. If a response is not received from TX, the determination process of S1308 is repeatedly executed. Also, if it is determined that a response has been received from TX, the process proceeds to S1309.
　Ｓ１３０９でＲＸは、ＴＸからの応答として、異物検出結果の通知メッセージ（ＦＯＤ　Ｓｔａｔｕｓ　Ｄａｔａ　Ｐａｃｋｅｔ）を受信したか否かを判定する。当該通知メッセージが受信されたことが判定された場合、Ｓ１３１０の処理に進み、当該通知メッセージが受信されていないと判定された場合、Ｓ１３１２の処理に移行する。 In S1309, RX determines whether or not it has received a foreign object detection result notification message (FOD Status Data Packet) as a response from TX. If it determines that the notification message has been received, it proceeds to S1310, and if it determines that the notification message has not been received, it proceeds to S1312.
　Ｓ１３１０でＲＸは異物検出結果を取得する。これは制御部２０１が通信部２０４により受信したメッセージから異物検出結果を取得することで実現できる。その後、Ｓ１３０３の処理に移行し、ＲＸは次の異物検出要求のタイミングを計る処理を実行する。 In S1310, RX obtains the foreign object detection result. This can be achieved by the control unit 201 obtaining the foreign object detection result from the message received by the communication unit 204. Then, the process proceeds to S1303, and RX executes a process to time the next foreign object detection request.
　Ｓ１３１１、Ｓ１３１２でＲＸは該当するメッセージの処理を実行する。Ｓ１３０６からＳ１３１１の処理に進む場合、Ｓ１３１１でＲＸは依頼メッセージ以外のメッセージに対応する所定の処理を実行した後、Ｓ１３０５の処理に移行する。また、Ｓ１３０９からＳ１３１２の処理に進む場合、Ｓ１３１２でＲＸは異物検出結果の通知メッセージ以外のメッセージに対応する所定の処理を実行した後、Ｓ１３０８の処理に移行する。 In S1311 and S1312, RX processes the corresponding message. When proceeding to S1311 from S1306, RX executes the predetermined process corresponding to a message other than a request message in S1311, and then proceeds to S1305. When proceeding to S1312 from S1309, RX executes the predetermined process corresponding to a message other than a foreign object detection result notification message in S1312, and then proceeds to S1308.
　本実施形態では、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにおいて図７（Ｃ）のようにＴＸが送電コイルグループを用いてＲＸに送電する。ＲＸが発行する異物検出実行要求（ＲＰパケット）を契機として、送電コイルグループを構成する全ての送電コイルで同時に波形減衰法による異物検出処理が実行される。 In this embodiment, in the Power Transfer Phase, the TX transmits power to the RX using the power transmission coil group as shown in FIG. 7(C). When the RX issues a foreign object detection execution request (RP packet), foreign object detection processing using the waveform attenuation method is executed simultaneously in all the power transmission coils that make up the power transmission coil group.
　取得される複数の異物検出結果に対して多数決原理により最終的な異物検出結果を得ることができる。ＴＸは、単一の送電コイルで実施される波形減衰法による異物検出処理に比較して、より正確な異物検出結果を取得してＲＸに通知することが可能である。 The final foreign object detection result can be obtained by majority voting from the multiple foreign object detection results obtained. The TX can obtain a more accurate foreign object detection result and notify the RX, compared to foreign object detection processing using the waveform attenuation method performed with a single transmitting coil.
　また、図１３のフローチャートでは図示を省略するが、Ｓ１３１０でＲＸは異物が存在することを示す情報を取得した場合、ＴＸに対して送電の制限を要求する信号を送信する。例えば送電の制限は、送電の停止や送電電力の低減を含む。ＴＸは送電の制限の要求にしたがって送電を停止させ、または送電電力を低下させる制御を行う。これにより、異物の発熱等にともなう損傷の回避が可能である。 Although not shown in the flowchart of FIG. 13, if the RX acquires information indicating the presence of a foreign object in S1310, it transmits a signal to the TX requesting a restriction on power transmission. For example, a restriction on power transmission includes stopping power transmission or reducing the transmission power. The TX performs control to stop power transmission or reduce the transmission power in accordance with the request to limit power transmission. This makes it possible to avoid damage caused by heat generation by the foreign object, etc.
　本実施形態によれば、送電コイルグループを構成し、単一の受電コイルを有する受電装置への送電を継続しつつ、波形減衰法による異物検出を適切に行うことができる。送電コイルグループによる送電中に異物が原因で引き起こされる事態を回避可能である。 According to this embodiment, a power transmission coil group is configured, and power transmission to a power receiving device having a single power receiving coil can be continued while foreign object detection using the waveform attenuation method can be appropriately performed. This makes it possible to avoid situations caused by foreign objects during power transmission by the power transmission coil group.
［第２実施形態］
　図１４を参照して、第２実施形態について説明する。本実施形態において第１実施形態と同様の事項に関する説明を割愛し、主に相違点を説明する。このような説明の省略方法は後述の実施形態でも同じである。 [Second embodiment]
A second embodiment will be described with reference to Fig. 14. In this embodiment, the description of the same matters as in the first embodiment will be omitted, and the description will be mainly focused on the differences. The method of omitting such description will be the same in the embodiments described later.
　図１４は、ＴＸが行う処理を説明するフローチャートである。以下の処理は、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　ＰｈａｓｅにてＲＸが異物検出実行要求をＴＸに送信するたびに繰り返し実行される。Ｓ１４０１からＳ１４０４の処理はそれぞれ、図１２のＳ１２０１からＳ１２０４の処理と同じである。 FIG. 14 is a flowchart explaining the processing performed by the TX. The following processing is repeatedly executed every time the RX sends a request to execute foreign object detection to the TX in the Power Transfer Phase. The processing from S1401 to S1404 is the same as the processing from S1201 to S1204 in FIG. 12, respectively.
　Ｓ１４０４の後、Ｓ１４０５の処理に進み、ＴＸは、波形減衰法による異物検出を実行する送電コイルの順番を確定する。本実施形態のＴＸは、送電コイルグループでの波形減衰法による異物検出として、複数の送電コイルで同時に電力を制御することはない。 After S1404, the process proceeds to S1405, where the TX determines the order of the power transmission coils that will perform foreign object detection using the waveform attenuation method. In this embodiment, the TX does not control power simultaneously in multiple power transmission coils for foreign object detection using the waveform attenuation method in a power transmission coil group.
　ＴＸは、複数の送電コイルの時分割制御を行い、逐次的に波形減衰法による異物検出を行う。Ｓ１４０５にてＴＸは、異物検出に係る実行順番を確定させる。実行順番の決定方法には、例えば、制御部１０１がランダムに決定する方法がある。この方法に限定されることなく、任意の決定方法の採用が可能である。次にＳ１４０６の処理に進む。 The TX performs time-sharing control of multiple power transmission coils and sequentially performs foreign object detection using the waveform attenuation method. In S1405, the TX determines the execution order for foreign object detection. The execution order can be determined, for example, by the control unit 101 randomly. However, the method is not limited to this, and any method can be used. Next, the process proceeds to S1406.
　Ｓ１４０６でＴＸは、Ｓ１４０５で確定した最初の送電コイルに対して波形減衰法による異物検出を行うための電力制御を実行する。送電制御部３０２は制御対象の送電コイルに対応するスイッチ部１０８を制御することにより、設定した時間だけ送電を停止することが可能である。 In S1406, the TX executes power control for the first power transmission coil determined in S1405 to detect a foreign object using the waveform attenuation method. The power transmission control unit 302 can stop power transmission for a set period of time by controlling the switch unit 108 corresponding to the power transmission coil to be controlled.
　次にＳ１４０７でＴＸは、電力制御を行った送電コイルに係るＱ値を取得する。そしてＳ１４０８でＴＸは、Ｓ１４０５で確定した実行順番に従い、対象となる全ての送電コイルで波形減衰法による異物検出を実行したか否かを判定する。 Next, in S1407, the TX acquires the Q value for the transmitting coil for which power control was performed. Then, in S1408, the TX determines whether or not foreign object detection using the waveform attenuation method has been performed for all target transmitting coils, according to the execution order determined in S1405.
　全ての送電コイルで波形減衰法による異物検出を実行したと判定された場合、Ｓ１４０９の処理に進み、まだ実行されていない送電コイルがある場合にはＳ１４０６に移行して次に指定される送電コイルに対して処理を続行する。 If it is determined that foreign object detection using the waveform attenuation method has been performed on all transmitting coils, the process proceeds to S1409, and if there are any transmitting coils that have not yet been detected, the process proceeds to S1406 and continues with the next specified transmitting coil.
　このように、本実施形態では、送電コイルグループ１１０１を構成する全ての送電コイルについて波形減衰法による異物検出が時分割方式で実行され、各送電コイルに係るＱ値が取得される。Ｓ１４０９からＳ１４１３までの処理は、Ｓ１２０７からＳ１２１１までの処理と同じである。またＲＸが行う処理については図１３にて説明したとおりである。 In this way, in this embodiment, foreign object detection using the waveform attenuation method is performed in a time-division manner for all of the power transmission coils that make up the power transmission coil group 1101, and the Q value for each power transmission coil is obtained. The processing from S1409 to S1413 is the same as the processing from S1207 to S1211. The processing performed by the RX is as described in FIG. 13.
　本実施形態では、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにおいて、図７（Ｃ）のようにＴＸが送電コイルグループを用いてＲＸに送電する。ＲＸが発行する異物検出実行要求（ＲＰパケット）を契機として、ＴＸは送電コイルグループを構成する全ての送電コイルを対象にして時分割で波形減衰法による異物検出を実行する。 In this embodiment, in the Power Transfer Phase, the TX transmits power to the RX using the power transmission coil group as shown in FIG. 7(C). When the RX issues a foreign object detection execution request (RP packet), the TX executes foreign object detection using the waveform attenuation method in a time-division manner for all the power transmission coils that make up the power transmission coil group.
　取得される複数の異物検出結果に対して多数決原理により最終的な異物検出結果を得ることができる。ＴＸは、より正確な異物検出結果を取得してＲＸに通知することが可能である。 The final foreign object detection result can be obtained by majority voting from the multiple foreign object detection results obtained. The TX can obtain a more accurate foreign object detection result and notify the RX.
［第２実施形態の変形実施形態］
　図１４のＳ１４０５では、時分割方式にて波形減衰法による異物検出に係る送電コイルの実行順番を無作為（ランダム）に決定する方法を説明した。変形実施形態では、各送電コイルに係る波形減衰指標（例えばＱ値）の順序にしたがって各送電コイルの実行順番が決定される。 [Modification of the second embodiment]
14, a method for randomly determining the execution order of the power transmitting coils related to foreign object detection using the waveform attenuation method in a time division manner has been described. In a modified embodiment, the execution order of the power transmitting coils is determined according to the order of the waveform attenuation indexes (e.g., Q values) related to the power transmitting coils.
　測定部３０３はＱ値計測法を用いて各送電コイルに係るＱ値を取得し、制御部１０１はＱ値の高低に従って実行順番を決定する。Ｑ値に基づく実行順番（順位）の決定方法には、Ｑ値が高い順に実行順番を高くする方法、またはＱ値が低い順に実行順番を高くする方法がある。 The measurement unit 303 obtains the Q value for each power transmission coil using a Q value measurement method, and the control unit 101 determines the execution order according to the high or low Q value. Methods for determining the execution order (rank) based on the Q value include a method of giving the highest execution order to the highest Q value, and a method of giving the highest execution order to the lowest Q value.
　あるいは、各送電コイルに係る結合状態指標（例えばｋ値）の順序にしたがって各送電コイルの実行順番を決定する方法がある。測定部３０３は各送電コイルに係るｋ値を計測し、制御部１０１はｋ値の高低に従って実行順番を決定する。ｋ値に基づく実行順番（順位）の決定方法には、ｋ値が高い順に実行順番を高くする方法、またはｋ値が低い順に実行順番を高くする方法がある。 Alternatively, there is a method of determining the execution order of each transmitting coil according to the order of the coupling state index (e.g., k value) for each transmitting coil. The measurement unit 303 measures the k value for each transmitting coil, and the control unit 101 determines the execution order according to the high or low k value. Methods for determining the execution order (rank) based on the k value include a method of assigning higher execution order to higher k value, or a method of assigning higher execution order to lower k value.
　また、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにおいて波形減衰法による異物検出は繰り返し実行される処理である。そのため、現時点よりの所定回数前（例えば１回前）に実行された、波形減衰法による異物検出の結果から各送電コイルの実行順番を決定する方法がある。 Furthermore, in the Power Transfer Phase, foreign object detection using the waveform attenuation method is a process that is executed repeatedly. Therefore, there is a method of determining the execution order of each power transmission coil from the result of foreign object detection using the waveform attenuation method executed a predetermined number of times before the current time (for example, one time before).
　過去に取得された異物検出結果（例えば前回検出された異物の存在確率）に基づく実行順番（順位）の決定方法には、異物の存在確率が高い順に実行順番を高くする方法、または異物の存在確率が低い順に実行順番を高くする方法がある。 The method of determining the execution order (rank) based on previously obtained foreign object detection results (for example, the probability of the presence of a foreign object detected last time) includes a method of assigning higher execution orders to the results with the highest probability of the presence of a foreign object, and a method of assigning higher execution orders to the results with the lowest probability of the presence of a foreign object.
［第３実施形態］
　本実施形態では、第１実施形態と第２実施形態に対して共通に適用可能な実施形態について説明する。図１２のＳ１２０４とＳ１２０５では、送電コイルグループ１１０１を構成する全ての送電コイルで波形減衰法による異物検出を実行する例を説明した。 [Third embodiment]
In this embodiment, an embodiment that can be commonly applied to the first and second embodiments will be described. In S1204 and S1205 in Fig. 12, an example in which foreign object detection is performed by the waveform attenuation method in all power transmitting coils that make up the power transmitting coil group 1101 has been described.
　本実施形態では、例えば図７のように３つの送電コイルによって送電コイルグループ１１０１が構成される場合、そのうちの１または２つの送電コイルを選択して波形減衰法による異物検出が実行される。 In this embodiment, for example, when a power transmission coil group 1101 is composed of three power transmission coils as shown in FIG. 7, one or two of the power transmission coils are selected and foreign object detection is performed using the waveform attenuation method.
　波形減衰法による異物検出を実行する送電コイルの選択方法を説明する。図１２と図１３に示す処理は、Ｐｏｗｅｒ　Ｔｒａｎｓｆｅｒ　Ｐｈａｓｅにおいて定期的に繰り返し実行される処理である。よって、処理の実行ごとに送電コイルを持ち回りで変更することが可能である。 A method for selecting a power transmission coil to perform foreign object detection using the waveform attenuation method will be described. The process shown in Figures 12 and 13 is a process that is periodically and repeatedly executed in the Power Transfer Phase. Therefore, it is possible to change the power transmission coil in a rotating manner each time the process is executed.
　例えば、送電コイルグループ１１０１（図７）を構成する３つの送電コイルをそれぞれ送電コイル１、送電コイル２、送電コイル３と表記する。１回目の処理の実行時には送電コイル１と送電コイル２の組が選択され、２回目の処理の実行時には送電コイル２と送電コイル３の組が選択される。 For example, the three power transmission coils that make up the power transmission coil group 1101 (Figure 7) are denoted as power transmission coil 1, power transmission coil 2, and power transmission coil 3, respectively. When the first process is executed, the pair of power transmission coil 1 and power transmission coil 2 is selected, and when the second process is executed, the pair of power transmission coil 2 and power transmission coil 3 is selected.
　３回目の処理の実行時では送電コイル３と送電コイル１の組が選択される。このような処理の実行ごとに組み合わせを変更する方法により、３回分の処理の実行が終了した時点で、送電コイル１、送電コイル２、送電コイル３が全て選択されて送電電力制御が行われたことになる。 When the process is executed a third time, the pair of transmitting coil 3 and transmitting coil 1 is selected. By changing the combination for each execution of the process in this way, when the process has been executed three times, transmitting coil 1, transmitting coil 2, and transmitting coil 3 have all been selected and transmission power control has been performed.
　また各送電コイルに係る波形減衰指標（例えばＱ値）の順序にしたがって送電コイルを選択する方法がある。測定部３０３はＱ値計測法によるＱ値を取得する。その値の高い順に所定の数だけ送電コイルが選択される。例えばＮ個の送電コイルに係るＱ値を、Ｑｊと表記し、ｊは１からＮのいずれかの自然数を表す変数である。 There is also a method of selecting transmitting coils according to the order of waveform attenuation indexes (e.g., Q values) associated with each transmitting coil. The measuring unit 303 acquires Q values using a Q value measurement method. A predetermined number of transmitting coils are selected in descending order of Q value. For example, the Q values associated with N transmitting coils are represented as Qj , where j is a variable representing any natural number from 1 to N.
　Ｑ値が高い順にＱｊを並べ替えて上位のＭ個のＱｊに対応する送電コイルが選択され、当該送電コイルで波形減衰法による異物検出が行われる。またＱ値が閾値（Ｑｓｈと記す）よりも高い送電コイル（Ｑｊ＞Ｑｓｈ）と、Ｑ値がＱｓｈよりも低い送電コイル（Ｑｊ＜Ｑｓｈ）の双方から所定数の送電コイルを選択する方法がある。 The Qj are sorted in descending order of Q value, and the power transmitting coils corresponding to the top M Qj are selected, and foreign object detection is performed using the power transmitting coils by the waveform attenuation method. There is also a method of selecting a predetermined number of power transmitting coils from both power transmitting coils whose Q value is higher than a threshold value (denoted as Qsh) ( Qj > Qsh) and power transmitting coils whose Q value is lower than Qsh ( Qj < Qsh).
　また各送電コイルに係る結合状態指標（例えばｋ値）の順序にしたがって送電コイルを選択する方法がある。測定部３０３は各送電コイルに係るｋ値を計測する。その値の高い順に所定の数だけ送電コイルが選択される。例えばＮ個の送電コイルに係るｋ値を、ｋｊと表記し、ｊは１からＮのいずれかの自然数を表す変数である。 There is also a method of selecting transmitting coils according to the order of coupling state indexes (e.g., k values) associated with each transmitting coil. The measurement unit 303 measures the k value associated with each transmitting coil. A predetermined number of transmitting coils are selected in descending order of the k value. For example, the k value associated with N transmitting coils is represented as kj , where j is a variable representing any natural number from 1 to N.
　ｋ値が高い順にｋｊを並べ替えて上位のＭ個のｋｊに対応する送電コイルが選択され、当該送電コイルで波形減衰法による異物検出が行われる。またｋ値が閾値（ｋｓｈと記す）よりも高い送電コイル（ｋｊ＞ｋｓｈ）と、ｋ値がｋｓｈよりも低い送電コイル（ｋｊ＜ｋｓｈ）の双方から所定数の送電コイルを選択する方法がある。 The kj are sorted in descending order of k value, and the power transmitting coils corresponding to the top M kj are selected, and foreign object detection is performed using the power transmitting coils by the waveform attenuation method. Another method is to select a predetermined number of power transmitting coils from both power transmitting coils whose k value is higher than a threshold value (denoted as ksh) ( kj > ksh) and power transmitting coils whose k value is lower than ksh ( kj < ksh).
　送電コイルグループ１１０１から波形減衰法による異物検出を実行する特定の送電コイルを選択する方法の実施においては、必要に応じて、送電コイルグループを構成する全ての送電コイルで波形減衰法による異物検出を実行することもできる。この場合、毎回特定の送電コイルを選択する処理が行われるのではなく、総回数のうちの所定の回数（例えば１回）では送電コイルグループ１１０１を構成する全ての送電コイルで波形減衰法による異物検出が実行される。 In implementing the method of selecting a specific power transmission coil from the power transmission coil group 1101 for performing foreign object detection using the waveform attenuation method, it is also possible to perform foreign object detection using the waveform attenuation method on all power transmission coils constituting the power transmission coil group, as necessary. In this case, the process of selecting a specific power transmission coil is not performed every time, but foreign object detection using the waveform attenuation method is performed on all power transmission coils constituting the power transmission coil group 1101 a predetermined number of times (e.g., once) out of the total number of times.
　送電コイルグループ１１０１から特定の送電コイルを選択して波形減衰法による異物検出を実行する方法によれば、送電中の全ての送電コイルで送電が同時に停止することはない。よって、送電停止に伴う電源喪失の可能性を抑制可能である。 By selecting a specific power transmission coil from the power transmission coil group 1101 and performing foreign object detection using the waveform attenuation method, power transmission is not stopped simultaneously for all power transmission coils that are currently transmitting power. This makes it possible to reduce the possibility of a power loss due to a power transmission stop.
　また、図１２のＳ１２０８と図１４のＳ１４１０では、取得された複数の異物検出結果に対して多数決原理で最終的な異物検出結果を得る方法を例示したが、この方法に限定されるものではない。例えば、波形減衰法による異物検出の結果として、異物の有無ではなく、異物の存在確率がある。その場合、ＴＸは取得された複数の異物検出結果の統計値を算出し、統計値をＲＸに通知する。 Furthermore, in S1208 of FIG. 12 and S1410 of FIG. 14, a method is illustrated in which a final foreign object detection result is obtained from the multiple foreign object detection results obtained by majority voting, but this is not limited to this method. For example, the result of foreign object detection using the waveform attenuation method is not the presence or absence of a foreign object, but the probability of the presence of a foreign object. In this case, the TX calculates a statistical value of the multiple foreign object detection results obtained and notifies the RX of the statistical value.
　統計値としては相加平均値、相乗平均値、中央値、最頻値等がある。あるいは、ＴＸは取得された複数の異物検出結果から１つを選んでＲＸに通知する方法がある。異物検出結果の選択方法には、異物の存在確率の最高値、最低値、または中央値を選ぶ方法がある。 Statistical values include arithmetic mean, geometric mean, median, mode, etc. Alternatively, the TX can select one from the multiple foreign object detection results obtained and notify the RX. Methods for selecting a foreign object detection result include selecting the highest, lowest, or median probability of the presence of a foreign object.
　複数の異物検出結果から最終的な異物検出結果を算出する前に、各送電コイルから取得された異物検出結果を補正する方法がある。例えば、ＴＸは各送電コイルについて取得された異物の存在確率の値に対し、送電中の各送電コイルに係る波形減衰指標（例えばＱ値）や、結合状態指標（例えばｋ値）を乗算する。つまりＴＸはＱ値またはｋ値を用いて重みづけによる補正を行った上で最終的な異物検出結果を算出する。 There is a method for correcting the foreign object detection results obtained from each transmitting coil before calculating the final foreign object detection result from multiple foreign object detection results. For example, the TX multiplies the value of the foreign object presence probability obtained for each transmitting coil by a waveform attenuation index (e.g., Q value) or a coupling state index (e.g., k value) for each transmitting coil during power transmission. In other words, the TX uses the Q value or k value to perform weighting correction before calculating the final foreign object detection result.
　ＴＸがＲＸに通知する異物検出結果については、１つに限定されることはない。複数の送電コイルから取得された全ての異物検出結果をＴＸがＲＸに通知する方法がある。このようにＴＸがＲＸに通知するための異物検出結果の決定（確定）方法は様々である。無線電力伝送システムに応じて適切な決定方法を用いることで、異物の検出精度をより高めることが可能である。 The foreign object detection result that the TX notifies the RX of is not limited to one. There is a method in which the TX notifies the RX of all foreign object detection results obtained from multiple transmission coils. In this way, there are various methods for determining (confirming) the foreign object detection result that the TX notifies of to the RX. By using an appropriate determination method depending on the wireless power transmission system, it is possible to further improve the accuracy of foreign object detection.
　図６のＦ５０６において基準となるＱ値の取得を行う例を説明したが、これに限定されるものではない。例えば、波形減衰法に関する前記第２の閾値設定方法で示したように、ＲＸがＮｅｇｏｔｉａｔｉｏｎ　Ｐｈａｓｅで送信するＦＯＤ　Ｓｔａｔｕｓ　Ｄａｔａ　Ｐａｃｋｅｔから取得されるＱ値情報を用いても構わない。 Although an example of obtaining the reference Q value has been described in F506 of FIG. 6, this is not limiting. For example, as shown in the second threshold setting method related to the waveform attenuation method, it is also possible to use the Q value information obtained from the FOD Status Data Packet sent by the RX in the Negotiation Phase.
　第１乃至第３実施形態の開示内容を、適宜に組み合わせてもよい。また、前記実施形態では、ＴＸが送電電力制御を行い、波形減衰指標（例えばＱ値）を用いて異物検出を行う例を示した。その他の方法として、ＴＸが複数の周波数成分を有する信号（例えば、パルス波）を送信し、その波形の振幅または減衰状態等を測定し、測定結果に対して演算処理（例えば、フーリエ変換）を行うことでＱ値を測定する方法がある。この方法を実施形態に適用することも可能である。 The contents disclosed in the first to third embodiments may be combined as appropriate. In the above embodiment, an example has been shown in which the TX controls the transmission power and detects foreign objects using a waveform attenuation index (e.g., Q value). As another method, the TX transmits a signal having multiple frequency components (e.g., a pulse wave), measures the amplitude or attenuation state of the waveform, and measures the Q value by performing arithmetic processing (e.g., Fourier transform) on the measurement results. This method can also be applied to the embodiments.
［その他の実施形態］
　本開示は、上述の実施形態の１以上の機能を実現するプログラムを、ネットワーク又は記憶媒体を介してシステム又は装置に供給し、そのシステム又は装置のコンピュータにおける１つ以上のプロセッサーがプログラムを読出し実行する処理でも実現可能である。また、１以上の機能を実現する回路（例えば、ＡＳＩＣ）によっても実現可能である。 [Other embodiments]
The present disclosure can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present disclosure can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.
（関連出願の相互参照）
　本出願は、先に出願された、２０２２年１１月２日に出願された日本特許出願第２０２２－１７６１５２号の利益を主張するものである。また、上記日本特許出願の内容は本明細書において参照によりその全体が本明細書に組み込まれる。

  CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of earlier filed Japanese Patent Application No. 2022-176152, filed on November 2, 2022. The contents of the above Japanese patent application are incorporated herein by reference in their entirety.

Claims (28)

  1. 　複数の送電コイルにより無線で受電装置に送電する送電手段と、
    　前記受電装置または前記受電装置とは異なる物体を検出する検出手段と、
    　前記受電装置と通信する通信手段と、
    　選択した複数の送電コイルにより前記送電手段が行う送電を制御する制御手段と、を備え、
    　前記制御手段は、前記送電手段が送電を開始した後に、送電波形の減衰状態に基づく前記物体の検出処理の実行要求を前記通信手段が前記受電装置から受信した場合、選択した前記複数の送電コイルによる送電を制限し、送電コイルごとに測定される前記減衰状態を表す指標を用いて、選択した前記複数の送電コイルにそれぞれ対応する、前記物体の検出結果を取得する制御を行う
    　ことを特徴とする送電装置。     A power transmitting unit that wirelessly transmits power to a power receiving device using a plurality of power transmitting coils;
    A detection means for detecting the power receiving device or an object other than the power receiving device;
    A communication means for communicating with the power receiving device;
    a control unit that controls power transmission performed by the power transmitting unit using a selected number of power transmitting coils;
    The control means, when the communication means receives a request from the power receiving device to execute a detection process for the object based on the attenuation state of the transmitted radio wave after the power transmitting means has started transmitting power, controls to limit power transmission by the selected plurality of power transmitting coils and to obtain detection results for the object corresponding to each of the selected plurality of power transmitting coils using an index representing the attenuation state measured for each of the power transmitting coils.
  2. 　前記制御手段は、前記送電手段が送電を開始する前に、前記物体が存在しない状態での前記指標である第１の指標を取得し、前記送電手段が送電を開始した後に、前記実行要求を前記通信手段が前記受電装置から受信した場合に第２の指標を取得して、前記第１および第２の指標を用いて前記物体の検出結果を取得する制御を行う
    　ことを特徴とする請求項１に記載の送電装置。     The power transmission device according to claim 1, characterized in that the control means obtains a first index, which is the index in a state in which the object is not present, before the power transmission means starts power transmission, and obtains a second index when the communication means receives the execution request from the power receiving device after the power transmission means starts power transmission, and controls the control to obtain a detection result of the object using the first and second indexes.
  3. 　前記制御手段は、前記物体に係る複数の検出結果のうち、最多数の検出結果から最終的な検出結果を確定する処理を行う
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means performs a process of determining a final detection result from a maximum number of detection results among a plurality of detection results related to the object.
  4. 　前記制御手段は、前記物体に係る複数の検出結果から統計値を算出する
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means calculates a statistical value from a plurality of detection results relating to the object.
  5. 　前記制御手段は、前記統計値として相加平均値、相乗平均値、中央値、または最頻値を算出する
    　ことを特徴とする請求項４に記載の送電装置。     The power transmitting device according to claim 4 , wherein the control means calculates an arithmetic mean, a geometric mean, a median, or a mode as the statistical value.
  6. 　前記制御手段は、前記物体に係る複数の検出結果から前記物体の存在確率を示す値を算出する
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means calculates a value indicating a probability of the presence of the object from a plurality of detection results relating to the object.
  7. 　前記制御手段は、前記物体の存在確率の最高値、最低値、または中央値を算出する
    　ことを特徴とする請求項６に記載の送電装置。     The power transmitting device according to claim 6 , wherein the control means calculates a maximum value, a minimum value, or a median value of the probability of the presence of the object.
  8. 　前記制御手段は、前記物体に係る複数の検出結果に対する重みづけを行って最終的な検出結果を算出する処理を行う
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means performs a process of weighting a plurality of detection results relating to the object to calculate a final detection result.
  9. 　前記制御手段は、前記物体に係る複数の検出結果に対し、前記送電コイルに対応する前記指標をそれぞれ乗算することにより重みづけを行う
    　ことを特徴とする請求項８に記載の送電装置。     The power transmitting device according to claim 8 , wherein the control means weights a plurality of detection results relating to the object by multiplying each of the detection results by the index corresponding to the power transmitting coil.
  10. 　前記制御手段は、選択された前記送電コイルと前記受電装置が有する受電アンテナとの電磁的な結合状態を表す結合状態指標を取得し、複数の前記物体の検出結果に対し、前記送電コイルに対応する前記結合状態指標をそれぞれ乗算することにより重みづけを行う
    　ことを特徴とする請求項８に記載の送電装置。     The power transmitting device according to claim 8, characterized in that the control means obtains a coupling state index representing an electromagnetic coupling state between the selected power transmitting coil and a power receiving antenna of the power receiving device, and weights the detection results of the multiple objects by multiplying each of the detection results by the coupling state index corresponding to the power transmitting coil.
  11. 　前記制御手段は、前記指標を取得する前に、選択された複数の前記送電コイルのうち、前記物体の検出に用いる特定の送電コイルを選択する制御を行う
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means performs control to select a specific power transmitting coil to be used for detecting the object from among the selected plurality of power transmitting coils before acquiring the index.
  12. 　前記制御手段は、前記指標の値によって前記特定の送電コイルを決定する
    　ことを特徴とする請求項１１に記載の送電装置。     The power transmitting device according to claim 11 , wherein the control means determines the specific power transmitting coil based on a value of the index.
  13. 　前記制御手段は、選択された前記送電コイルと前記受電装置が有する受電アンテナとの電磁的な結合状態を表す結合状態指標を取得し、前記結合状態指標の値によって前記特定の送電コイルを決定する
    　ことを特徴とする請求項１１に記載の送電装置。     The power transmitting device according to claim 11, characterized in that the control means acquires a coupling state index representing an electromagnetic coupling state between the selected power transmitting coil and a power receiving antenna of the power receiving device, and determines the specific power transmitting coil based on a value of the coupling state index.
  14. 　前記制御手段は、選択された前記送電コイルのうち、前記特定の送電コイルを用いて前記検出手段により前記物体を検出する第１の制御と、選択された全ての送電コイルを用いて前記検出手段により前記物体を検出する第２の制御を行う
    　ことを特徴とする請求項１１に記載の送電装置。     The power transmitting device according to claim 11, characterized in that the control means performs a first control in which the object is detected by the detection means using the specific power transmitting coil among the selected power transmitting coils, and a second control in which the object is detected by the detection means using all of the selected power transmitting coils.
  15. 　前記制御手段は、予め定めた回数のうち、第１の回数で前記第１の制御を行い、第２の回数で前記第２の制御を行う
    　ことを特徴とする請求項１４に記載の送電装置。     The power transmitting device according to claim 14 , wherein the control unit performs the first control a first number of times and performs the second control a second number of times among a predetermined number of times.
  16. 　前記制御手段は、選択された前記複数の送電コイルを用いて前記検出手段により前記物体を検出する処理を同時に実行する
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means simultaneously executes a process of detecting the object by the detection means using the selected power transmitting coils.
  17. 　前記制御手段は、選択された前記複数の送電コイルを用いて前記検出手段により前記物体を検出する処理を時分割で実行する
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means executes a process of detecting the object by the detection means using the selected power transmitting coils in a time-division manner.
  18. 　前記制御手段は、選択された前記複数の送電コイルに対し、前記物体の検出に係る実行順番を無作為に決定する
    　ことを特徴とする請求項１７に記載の送電装置。     The power transmitting device according to claim 17 , wherein the control means randomly determines an execution order for the object detection for the selected power transmitting coils.
  19. 　前記制御手段は、選択された前記複数の送電コイルに対し、前記物体の検出に係る実行順番を前記指標の順序により決定する
    　ことを特徴とする請求項１７に記載の送電装置。     The power transmitting device according to claim 17 , wherein the control means determines an execution order of the object detection for the selected power transmitting coils based on an order of the indexes.
  20. 　前記制御手段は、選択された前記送電コイルと前記受電装置が有する受電アンテナとの電磁的な結合状態を表す結合状態指標を取得し、前記物体の検出に係る実行順番を前記結合状態指標の順序により決定する
    　ことを特徴とする請求項１７に記載の送電装置。     The power transmitting device according to claim 17, characterized in that the control means obtains a coupling state index representing an electromagnetic coupling state between the selected power transmitting coil and a power receiving antenna of the power receiving device, and determines an execution order for detecting the object based on an order of the coupling state indexes.
  21. 　前記制御手段は、選択された前記複数の送電コイルに対し、前記物体の検出に係る実行順番を過去に取得された前記物体の異物検出結果の順序により決定する
    　ことを特徴とする請求項１７に記載の送電装置。     The power transmitting device according to claim 17 , wherein the control means determines an execution order of the object detection for the selected power transmitting coils based on an order of previously obtained foreign object detection results for the object.
  22. 　前記制御手段は、取得された前記物体の検出結果を前記受電装置が取得することを依頼する制御を行う
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means performs control to request the power receiving device to acquire the acquired detection result of the object.
  23. 　前記制御手段は、前記通信手段により前記受電装置から前記物体の検出結果の取得を要求する信号を受信した場合、前記物体の検出結果を、前記通信手段により前記受電装置に送信する制御を行う
    　ことを特徴とする請求項２２に記載の送電装置。     The power transmitting device according to claim 22, characterized in that, when the control means receives a signal from the power receiving device via the communication means requesting acquisition of the object detection result, the control means controls the communication means to transmit the object detection result to the power receiving device.
  24. 　前記検出手段は、前記送電コイルを介して出力される信号により前記受電装置または物体の検出を行い、
    　前記制御手段は、前記送電コイルを介して出力される信号の変化に基づく前記第１の指標を取得する
    　ことを特徴とする請求項２に記載の送電装置。     the detection means detects the power receiving device or the object based on a signal output via the power transmitting coil;
    The power transmitting device according to claim 2 , wherein the control means obtains the first index based on a change in a signal output via the power transmitting coil.
  25. 　前記制御手段は、前記受電装置への送電を停止させる制御、または送電電力を低減させる制御によって、前記複数の送電コイルによる送電を制限する
    　ことを特徴とする請求項１に記載の送電装置。     The power transmitting device according to claim 1 , wherein the control means limits power transmission from the plurality of power transmitting coils by performing control to stop power transmission to the power receiving device or control to reduce transmitted power.
  26. 　請求項１に記載の送電装置から、受電アンテナを介して受電することが可能な受電手段と、
    　前記送電装置と通信する通信手段と、
    　前記受電手段を制御する制御手段と、を備え、
    　前記通信手段が、前記送電装置から、前記物体の検出結果を前記受電装置が取得することを依頼する信号を受信した場合、前記受電装置の制御手段は、前記物体の検出結果の取得を要求する信号を前記通信手段により前記送電装置に送信する制御を行う
    　ことを特徴とする受電装置。     A power receiving unit capable of receiving power from the power transmitting device according to claim 1 via a power receiving antenna;
    A communication means for communicating with the power transmitting device;
    A control means for controlling the power receiving means,
    A power receiving device characterized in that, when the communication means receives a signal from the power transmitting device requesting that the power receiving device obtain the detection results of the object, the control means of the power receiving device controls the communication means to send a signal requesting the acquisition of the detection results of the object to the power transmitting device.
  27. 　複数の送電コイルにより無線で受電装置に送電することが可能な送電装置にて実行される制御方法であって、
    　前記受電装置または前記受電装置とは異なる物体を検出する検出工程と、
    　通信手段が前記受電装置と通信する通信工程と、
    　前記受電装置に対して送電手段が送電を行う送電工程と、
    　選択した複数の送電コイルにより前記送電手段が行う送電を制御手段が制御する制御工程と、を有し、
    　前記制御工程にて制御手段は、前記送電手段が送電を開始した後に、送電波形の減衰状態に基づく前記物体の検出処理の実行要求を前記通信手段が前記受電装置から受信した場合、選択した前記複数の送電コイルによる送電を制限し、送電コイルごとに測定される前記減衰状態を表す指標を用いて、選択した前記複数の送電コイルにそれぞれ対応する、前記物体の検出結果を取得する制御を行う
    　ことを特徴とする送電装置の制御方法。     A control method executed in a power transmitting device capable of wirelessly transmitting power to a power receiving device using a plurality of power transmitting coils, comprising:
    A detection step of detecting the power receiving device or an object other than the power receiving device;
    a communication step in which a communication means communicates with the power receiving device;
    a power transmitting step in which a power transmitting unit transmits power to the power receiving device;
    A control step of controlling power transmission performed by the power transmission means through a selected plurality of power transmission coils by a control means,
    A control method for a power transmission device, characterized in that in the control step, when the communication means receives a request from the power receiving device to execute a detection process for the object based on an attenuation state of a transmitted radio wave after the power transmission means starts transmitting power, the control means performs control to limit power transmission by the selected multiple power transmission coils and obtain detection results for the object corresponding to each of the selected multiple power transmission coils using an index representing the attenuation state measured for each power transmission coil.
  28. 　複数の送電コイルにより無線で受電装置に送電することが可能な送電装置において以下の複数の工程をコンピュータに実行させるためのコンピュータプログラムを記憶した記憶媒体であって、
    　複数の工程は、
    　前記受電装置または前記受電装置とは異なる物体を検出する検出工程と、
    　通信手段が前記受電装置と通信する通信工程と、
    　前記受電装置に対して送電手段が送電を行う送電工程と、
    　選択した複数の送電コイルにより前記送電手段が行う送電を制御手段が制御する制御工程と、を有し、
    　前記制御工程にて制御手段は、前記送電手段が送電を開始した後に、送電波形の減衰状態に基づく前記物体の検出処理の実行要求を前記通信手段が前記受電装置から受信した場合、選択した前記複数の送電コイルによる送電を制限し、送電コイルごとに測定される前記減衰状態を表す指標を用いて、選択した前記複数の送電コイルにそれぞれ対応する、前記物体の検出結果を取得する制御を行うものであることを特徴とする記憶媒体。

          A storage medium storing a computer program for causing a computer to execute the following steps in a power transmission device capable of wirelessly transmitting power to a power receiving device using a plurality of power transmission coils,
    The multiple steps are
    A detection step of detecting the power receiving device or an object other than the power receiving device;
    a communication step in which a communication means communicates with the power receiving device;
    a power transmitting step in which a power transmitting unit transmits power to the power receiving device;
    A control step of controlling the power transmission performed by the power transmission means through the selected plurality of power transmission coils by a control means,
    A storage medium characterized in that in the control process, when the communication means receives a request from the power receiving device to execute a detection process for the object based on the attenuation state of the transmitted radio wave after the power transmitting means starts transmitting power, the control means controls to limit power transmission by the selected multiple power transmitting coils and obtain detection results for the object corresponding to each of the selected multiple power transmitting coils using an index representing the attenuation state measured for each power transmitting coil.
PCT/JP2023/031862 2022-11-02 2023-08-31 Electric power transfer device and method for controlling same, electric power receiver, and storage medium WO2024095592A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020114170A (en) * 2019-01-14 2020-07-27 エルジー エレクトロニクス インコーポレイティド Wireless power transmission device
WO2021161966A1 (en) * 2020-02-14 2021-08-19 キヤノン株式会社 Power transmission device and power receiving device, and control method and program therefor
US20220052561A1 (en) * 2020-08-16 2022-02-17 Aira, Inc. Adaptive Foreign Object Detection Avoidance In A Multi-Coil Wireless Charging Device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020114170A (en) * 2019-01-14 2020-07-27 エルジー エレクトロニクス インコーポレイティド Wireless power transmission device
WO2021161966A1 (en) * 2020-02-14 2021-08-19 キヤノン株式会社 Power transmission device and power receiving device, and control method and program therefor
US20220052561A1 (en) * 2020-08-16 2022-02-17 Aira, Inc. Adaptive Foreign Object Detection Avoidance In A Multi-Coil Wireless Charging Device

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