WO2013125425A1 - Power conversion device and direct-current system - Google Patents
Power conversion device and direct-current system Download PDFInfo
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- WO2013125425A1 WO2013125425A1 PCT/JP2013/053464 JP2013053464W WO2013125425A1 WO 2013125425 A1 WO2013125425 A1 WO 2013125425A1 JP 2013053464 W JP2013053464 W JP 2013053464W WO 2013125425 A1 WO2013125425 A1 WO 2013125425A1
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- target value
- power conversion
- path
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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
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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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
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
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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
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
- H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Definitions
- the present invention relates to a power converter, and more particularly to power conversion control of a power converter applied to a DC system that supplies DC power.
- each of a plurality of power supply units connected to a DC bus has a current control unit, and the current control unit A configuration having a function of autonomously changing a DC voltage command value or DC voltage controllability in accordance with a current input / output to / from a corresponding power supply unit is disclosed.
- the DC system described in Patent Document 1 allows a plurality of distributed power supplies to autonomously operate in a coordinated manner and easily add a power supply unit without depending on the device capacity.
- the voltage of the DC bus is stabilized without control by directly connecting a voltage source having a high voltage stabilizing capability such as a storage battery to the DC bus without using a power converter. Is possible.
- a storage battery normally has “allowable charging current” and “allowable discharge current” that can be passed through the storage battery according to its specifications.
- the storage battery is likely to deteriorate. Therefore, it is necessary to control the charging / discharging current of the storage battery so as not to exceed the allowable charging current and the allowable discharging current.
- the allowable charging current and the allowable discharging current may be described as a rated current.
- the influence of fluctuations in power transferred to and from the DC bus extends to a power conversion device that performs power conversion between the DC bus and the system power. If the power sent to or received from the DC bus fluctuates, the balance of power balance between the DC bus and the power converter may be disrupted, possibly resulting in power exceeding the rated output of the power converter. There is.
- the present invention has been made to solve such a problem, and an object thereof is to protect the power storage device in a DC system in which the power storage device is directly connected to the DC bus without using a power converter.
- Another object of the present invention is to protect a power converter that converts power between the DC bus and system power in a DC system in which a power storage device is directly connected to the DC bus without a power converter.
- the power converter is connected to a DC bus disposed between the power storage device and the system power.
- the power conversion device includes a power conversion unit that converts power between a DC bus and system power, a self-path current detection unit that detects a self-path current flowing through the power conversion unit, and a charge / discharge that acquires a charge / discharge current of the power storage device A current acquisition unit and a control unit that controls the power conversion unit are provided.
- the control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the self-path current becomes a control target value, and the acquired charge / discharge current is predetermined during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
- the adjustment means responds to the charge / discharge current when the charge / discharge current when the power conversion control means is executed with the predetermined control target value set to an initial value exceeds a predetermined current range.
- the control target value is set to the initial value while controlling the charging / discharging current within a predetermined current range. And return means for returning to.
- the adjustment means responds to the charge / discharge current when the charge / discharge current when the power conversion control means is executed with the predetermined control target value set to an initial value exceeds a predetermined current range.
- the charge / discharge current is in a state where the charge / discharge current is within a predetermined current range. Returning means for returning the control target value to the initial value when it has changed is included.
- the power converter is connected to a DC bus disposed between the power storage device and the system power.
- the power converter includes a power converter that converts power between the DC bus and the grid power, a self-path current detector that detects a self-path current that flows through the power converter, and a charge / discharge that acquires a charge / discharge current of the power storage device
- a current acquisition unit and a control unit that controls the power conversion unit are provided.
- the control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the charge / discharge current becomes a control target value, and a detected value of the own path current is predetermined during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
- the adjusting means sets the predetermined control target value as an initial value, and when the detected value of the self-path current when the power conversion control means is executed exceeds a predetermined current range, the self-path current During the execution of the change means for changing the control target value according to the detected value and the power conversion control means using the changed control target value, the detected value of the own path current is controlled within a predetermined current range.
- a return means for returning the control target value to the initial value is included.
- the adjusting means sets the predetermined control target value as an initial value, and when the detected value of the self-path current when the power conversion control means is executed exceeds a predetermined current range, the self-path current During the execution of the changing means for changing the control target value according to the detected value and the power conversion control means using the changed control target value, the detected value of the own path current falls within a predetermined current range. And a return means for returning the control target value to the initial value when the detected value of the self-path current changes.
- a DC system includes a DC bus, a power storage device that outputs a power supply voltage to the DC bus, a power converter connected between the DC bus and the system power, and a power converter.
- a self-path current detection unit that detects a flowing self-path current and a charge / discharge current detection unit that detects a charge / discharge current of the power storage device.
- the power conversion device includes a power conversion unit that converts power between a DC bus and system power, and a control unit that controls the power conversion unit.
- the control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the self-path current becomes a control target value, and a detection value of the charge / discharge current is predetermined during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
- a DC system includes a DC bus, a power storage device that outputs a power supply voltage to the DC bus, a power converter connected between the DC bus and the system power, and a power converter.
- a self-path current detection unit that detects a flowing self-path current and a charge / discharge current detection unit that detects a charge / discharge current of the power storage device.
- the power conversion device includes a power conversion unit that converts power between a DC bus and system power, and a control unit that controls the power conversion unit.
- the control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the charge / discharge current becomes a control target value, and a detection value of the own path current is a predetermined value during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
- the power storage device and the power conversion device can be protected in the DC system in which the power storage unit is directly connected to the DC bus without the power converter.
- FIG. 1 is a diagram schematically showing an overall configuration of a DC system to which a power conversion device according to an embodiment of the present invention is applied.
- FIG. It is a circuit diagram which shows the detailed structure of the bidirectional
- FIG. 1 schematically shows an overall configuration of a DC system to which a power conversion device according to an embodiment of the present invention is applied.
- the DC system includes a DC bus 1, a photovoltaic power generation system 2, a power storage device 3, a grid power system 4, a DC load 5, and a battery monitoring unit 6. Prepare.
- the DC bus 1 supplies DC power to DC load 5.
- the DC load 5 is, for example, an electric device such as an air conditioner, a refrigerator, a washing machine, a television, a lighting device, or a personal computer used at home. Alternatively, it may be an electric device such as a computer, a copier or a facsimile used in an office, or an electric device such as a showcase or a lighting device used in a store.
- a solar power generation system 2, a power storage device 3, and a system power system 4 are connected to the DC bus 1.
- the power storage device 3 includes, for example, a secondary battery configured to be chargeable / dischargeable, such as a lithium ion secondary battery.
- the power storage device 3 is configured by connecting a plurality of battery cells in series.
- the power storage device 3 has a rated voltage of 400 V and a rated capacity of 4 kWh.
- the power storage device 3 is “directly connected” to the DC bus 1, and exchanges DC power with the DC bus 1.
- “directly connected” means that a power converter such as a DC / DC converter is not interposed between the DC bus 1 and the power storage device 3. Therefore, the voltage of DC bus 1 is substantially equal to the power supply voltage of power storage device 3.
- Battery monitoring unit 6 detects the state value of power storage device 3 based on the outputs of current sensor 60, voltage sensor 62 and temperature sensor 64 provided in power storage device 3. Specifically, current sensor 60 detects charge / discharge current Ib that is inserted in DC bus 1 and input / output to / from power storage device 3, and outputs the detected value to battery monitoring unit 6. Voltage sensor 62 detects charge / discharge voltage Vb of power storage device 3 and outputs the detected value to battery monitoring unit 6. Temperature sensor 64 detects temperature Tb of power storage device 3 and outputs the detected value to battery monitoring unit 6. As described above, since a secondary battery is typically used as power storage device 3, current Ib, voltage Vb, and temperature Tb of power storage device 3 will be described below as battery current Ib, battery voltage Vb, and battery temperature Tb. Called.
- Current sensor 60 detects charging current Ich to power storage device 3 as positive battery current Ib, and detects discharge current Idc from power storage device 3 as negative battery current Ib.
- the current sensor 60 corresponds to a “charge / discharge current detector”.
- power storage device 3 is directly connected to direct current bus 1, and bidirectional DC / AC converter 40 is configured by a full bridge inverter, as will be described later.
- bidirectional DC / AC converter 40 is configured by a full bridge inverter, as will be described later.
- the current sensor 60 detects the average value of the battery current Ib. Alternatively, the peak value of the battery current Ib may be detected.
- the battery monitoring unit 6 Based on the detected value of the battery current Ib from the current sensor 60, the detected value of the battery voltage Vb from the voltage sensor 62, and the detected value of the battery temperature Tb from the temperature sensor 64, the battery monitoring unit 6 Estimate the remaining amount (SOC: State of Charge). The SOC is a percentage of the current remaining capacity with respect to the full charge capacity. For example, the battery monitoring unit 6 calculates the estimated SOC value based on the relationship between the open circuit voltage (OCV) of the power storage device 3 and the SOC. Alternatively, the estimated SOC value may be calculated sequentially based on the integrated value of the charge / discharge amount of power storage device 3.
- OCV open circuit voltage
- the integrated value of the charge / discharge amount can be obtained by temporally integrating the product (electric power) of the battery current Ib and the battery voltage Vb.
- the battery current Ib, the battery voltage Vb, the battery temperature Tb, and the estimated SOC value are collectively referred to as “battery data”.
- the solar power generation system 2 includes a solar cell 20 and a DC / DC converter 22.
- the solar cell 20 is composed of a crystalline solar cell, a polycrystalline solar cell, a thin film solar cell, or the like.
- the DC / DC converter 22 is disposed between the solar cell 20 and the DC bus 1, converts the DC power received from the solar cell 20 into a voltage, and supplies it to the DC bus 1.
- the voltage conversion operation in the DC / DC converter 22 is performed by a control unit (not shown) according to the output voltage of the solar battery 20 and the voltage of the DC bus 1 (the line voltage between the positive bus PL and the negative bus NL). It is controlled according to the switching command. Specifically, when the voltage of DC bus 1 is lower than 420 V (corresponding to the power supply voltage of power storage device 3 when fully charged), DC / DC converter 22 causes solar cell 20 to follow the maximum power point ( MPPT) control. When the voltage of the DC bus 1 reaches 420V, the DC / DC converter 22 controls the solar battery 20 by switching from the maximum power point control to the control for maintaining the voltage of the DC bus 1 at 420V.
- system power system 4 exchanges DC power with DC bus 1.
- the grid power system 4 includes a bidirectional DC / AC converter 40 and a grid power 42.
- the grid power 42 is power received from an electric power company or the like (for example, AC 200V).
- the system power 42 is supplied from, for example, a single-phase three-phase commercial AC power system.
- the neutral wire is grounded via a resistor, and AC200V is supplied using two wires (R-phase wire RL and T-phase wire TL) other than the neutral wire. .
- the bidirectional DC / AC converter 40 is connected between the DC bus 1 and the system power 42.
- Bidirectional DC / AC converter 40 converts the DC power received from DC bus 1 into AC power and supplies it to system power 42. Further, the bidirectional DC / AC converter 40 converts AC power received from the system power 42 into DC power and supplies it to the DC bus 1.
- system power is purchased from an electric power company or the like (power purchase) via bidirectional DC / AC converter 40, and surplus power is supplied via bidirectional DC / AC converter 40. It is configured to be able to sell (power sale) to companies.
- the self-path current during power purchase is Ibuy
- the self-path current during power sale is Icell. Is written. Further, the current supplied to the DC load 5 is expressed as Iload, and the current supplied from the solar power generation system 2 to the DC bus 1 is expressed as Ipv.
- a current obtained by subtracting the current Iload from the sum of the current Ipv and the current Ibuy becomes the charging current Ich of the power storage device 3.
- a current obtained by subtracting current Iload from the sum of current Ipv and discharge current Idc of power storage device 3 is current Icell.
- the values of the currents Isel and Ibuy can be freely set by the user or administrator of the DC system.
- bidirectional DC / AC converter 40 (Configuration of bidirectional DC / AC converter) Next, with reference to the drawings, the configuration of bidirectional DC / AC converter 40 which is one form of the power conversion device according to the embodiment of the present invention will be described.
- FIG. 2 is a circuit diagram showing a detailed configuration of the bidirectional DC / AC converter 40 in FIG.
- bidirectional DC / AC converter 40 includes a bidirectional inverter 400, interconnection reactors 410 and 412, a current sensor 430, a voltage sensor 440, and a control unit 420.
- the bidirectional inverter 400 converts the DC power received from the DC bus 1 into AC power and outputs it to the system power 42 in response to the switching control signals S1 to S4 from the control unit 420 at the time of power sale.
- Bidirectional inverter 400 converts AC power received from system power 42 into DC power and outputs it to DC bus 1 in accordance with switching control signals S 1 to S 4 from control unit 420 during power purchase.
- the bidirectional inverter 400 includes transistors Q1 to Q4, which are switching elements, and diodes D1 to D4. Transistors Q1 and Q2 are connected in series between positive bus PL and negative bus NL constituting DC bus 1. An intermediate point between transistors Q1 and Q2 is connected to R-phase line RL. Interconnection reactor 410 is connected to R-phase line RL.
- Transistors Q3 and Q4 are connected in series between positive bus PL and negative bus NL. An intermediate point between transistors Q3 and Q4 is connected to T-phase line TL. Interconnected reactor 412 is connected to T-phase line TL. Between the collector and emitter of each of the transistors Q1 to Q4, diodes D1 to D4 that flow current from the emitter side to the collector side are respectively connected. Transistors Q1-Q4 and diodes D1-D4 constitute a full bridge circuit.
- IGBTs Insulated Gate Bipolar Transistors
- MOSFET Metal Oxide Semiconductor Field-Effect Transistor
- Current sensor 430 is inserted in negative bus SL, detects a current value (own path current) Iinv of power exchanged between DC bus 1 and bidirectional inverter 400, and outputs the detection result to control unit 420. To do.
- the current sensor 430 corresponds to a “self-path current detection unit”.
- Voltage sensor 440 is connected between positive bus PL and negative bus SL, detects voltage value Vdc of power transferred between bidirectional inverter 400 and system power 42, and outputs the detection result to control unit 420. Output.
- the voltage Vdc of the DC bus 1 is equal to the battery voltage Vb. In reality, a slight voltage difference is generated between the voltage value Vd1 and the battery voltage Vb due to the wiring impedance, but it is assumed to be negligibly small in the present embodiment.
- the control unit 420 includes the own path current Iinv received from the current sensor 430, the voltage Vdc received from the voltage sensor 44, the battery current Ib received from the current sensor 60, and battery data (battery voltage Vb from the battery monitoring unit 6). Based on the battery temperature Tb and the remaining battery charge SOC), the switching control signals S1 to S4 for controlling on / off of the transistors Q1 to Q4 are generated according to the control structure described later, and the bidirectional inverter 400 is controlled. To do.
- control unit 420 sets a control target value in the bidirectional inverter 400.
- This control target value includes a current target value Inv * of the own path current Iinv and a current target value Ib * of the battery current Ib.
- the current target value Iinv * of the own path current Iinv is also referred to as “own path current target value”
- the current target value Ib * of the battery current Ib is also referred to as “battery current target value”.
- the control target values are determined in advance so as to be different values depending on, for example, the date and time or the remaining battery level (SOC) of the power storage device 3, and are not illustrated. Can be stored in memory.
- FIG. 3 is a diagram illustrating an example of a target value setting table used by the bidirectional DC / AC converter 40.
- the battery current is represented with the charging direction of the power storage device 3 as a positive direction and the discharge direction of the power storage device 3 as a negative direction.
- the self-path current Iinv is described with the power selling direction as the positive direction and the power purchase direction as the negative direction.
- Battery current target value Ib * includes current target value Ich * of charging current Ich and current target value Idc * of discharge current Idc.
- the own path current target value Iinv * includes a current target value Isel * of the own path current Isel at the time of power sale and a current target value Ibuy * of the own path current Ibuy at the time of power purchase.
- Control unit 420 sets own path current target value Iinv * or battery current target value Ib * according to the date and time and the remaining battery level of power storage device 3 in accordance with the target value setting table shown in FIG. Or you may make it acquire the control target value set according to the target value setting table
- the control unit 420 controls the bidirectional inverter 400 by generating the switching control signals S1 to S4 so that the own path current Iinv becomes the own path current target value Iinv *.
- the control unit 420 controls the bidirectional inverter 400 by generating the switching control signals S1 to S4 so that the battery current Ib becomes the battery current target value Ib *.
- the current control based on the own path current target value Iinv * is also referred to as “own path current control”, and the current control based on the battery current target value Ib * is “ Also referred to as “battery current control”.
- FIGS. 4 and 5 are diagrams for explaining self-path current control in bidirectional DC / AC converter 40 according to the embodiment of the present invention.
- the range of current that can be passed through the power storage device 3 is determined due to its specifications. This current range is determined based on the rated capacity of power storage device 3, for example.
- 1C 10 A is set as the upper and lower limit values of the current range. That is, the battery current Ib needs to fall within the range of ⁇ 10A to 10A.
- the battery current Ib when the battery current Ib deviates from a predetermined current range during execution of current control according to the self-path current target value Iinv *, the battery current Ib is within the current range.
- the own path current target value Iinv * is adjusted.
- the bidirectional DC / AC converter 40 sets the self-path current target value Iinv *.
- the self-path current target is set so that battery current Ib falls within the current range with self-path current target value Iinv * set based on the target value setting table of FIG. 3 as an initial value. Adjust the value Iinv *.
- FIG. 6 is a diagram illustrating a control structure of the control unit 420 in FIG.
- control unit 420 includes a control target value generation unit 500, a switching element control signal generation unit 510, and a memory 520.
- the control target value generation unit 500 generates the own path current target value Iinv ** as the control target value of the bidirectional DC / AC converter 40.
- the self-path current target value Iinv ** is set to the initial value of the self-path current target value Iinv * determined according to the target value setting table of FIG. 3, and the battery current Ib during execution of the self-path current control It corresponds to the self-path current target value after being adjusted according to.
- the switching element control signal generation unit 510 When the switching element control signal generation unit 510 receives the own path current target value Iinv ** from the control target value generation unit 500, the switching element control signal generation unit 510 switches the switching control signals S1 to S1 so that the own path current Iinv becomes the own path current target value Iinv **. S4 is generated and the bidirectional DC / AC converter 40 is controlled.
- the switching element control signal generation unit 510 is configured to include at least a proportional element (P) and an integral element (I), and the self-path current with respect to the self-path current target value Iinv **. An operation signal is generated according to the deviation of Iinv. Then, switching element control signal generation unit 510 generates a duty command that defines the on-duty of transistors Q1 to Q4 of bidirectional inverter 400 (FIG. 2) based on this operation signal. Are generated, the switching control signals S1 to S4 are generated.
- the memory 520 can read and write information, and is composed of, for example, a RAM (Random Access Memory).
- Memory 520 has a storage area for storing target value setting table (FIG. 3), a predetermined current range in power storage device 3, and battery data that is sequentially updated according to the specifications of power storage device 3.
- target value setting table FIG. 3
- detection information of the battery current Ib transmitted from the current sensor 60 battery current detection information
- detection information of the own path current Iinv transmitted from the current sensor 430 own path current detection information
- Control target value generation unit 500 receives self-path current Iinv from current sensor 430, battery current Ib from current sensor 60, and battery remaining amount (SOC) of power storage device 3 from battery monitoring unit 6.
- the control target value generation unit 500 generates the own path current target value Iinv ** based on the input information and the information stored in the memory 520.
- the control target value generation unit 500 receives the remaining battery level of the power storage device 3 from the battery monitoring unit 6, but the control target value generation unit 500 itself detects the detection information of the battery current Ib and / or Or it is good also as a structure which estimates the battery remaining charge of the electrical storage apparatus 3 based on the detection information of the battery voltage Vb.
- the estimated SOC value may be calculated by referring to the relationship between the OCV and the SOC of the power storage device 3 based on the detected value of the battery voltage Vb transmitted from the voltage sensor 62.
- FIG. 7 is a flowchart showing a control processing procedure for realizing the self-path current control of the power conversion device according to the present embodiment.
- the control process according to the flowchart shown in FIG. 7 is executed by the control unit 420 at regular intervals.
- each step illustrated in FIG. 7 is realized by software processing and / or hardware processing by the control unit 420.
- control unit 420 sets current target value Iinv ** of self-path current Iinv in step S100.
- control unit 420 refers to target value setting table (FIG. 3) stored in memory 520 to determine self-path current target value Iinv * based on the date and time and the remaining battery level of power storage device 3.
- target value setting table FIG. 3
- the process of step S100 corresponds to the function of the control target value generation unit 500.
- Control unit 420 sets self-path current target value Iinv * determined according to the target value setting table (FIG. 3) as an initial value of self-path current target value Iinv **. That is, initial value Iinv * is a variable value that changes according to the date and time and the remaining battery level of power storage device 3.
- control unit 420 generates switching control signals S1 to S4 so that self-path current Iinv becomes self-path current target value Iinv **, and controls bidirectional inverter 400 (current control). ).
- control unit 420 acquires the battery current Ib (battery current detection information) detected by the current sensor 60 during the power conversion operation in the bidirectional inverter 400 in step S300, the acquired battery current is acquired. Based on Ib, the self-path current target value Iinv ** is adjusted. Specifically, control unit 420 compares the current range of power storage device 3 stored in memory 520 with battery current Ib. Then, the control unit 420 adjusts the own path current target value Iinv ** based on the comparison result.
- the function of step S300 corresponds to the function of the control target value generation unit 500 shown in FIG.
- FIG. 8 is a flowchart for explaining the processing in steps S200 and S300 in FIG. 7 in more detail.
- control unit 420 compares self-path current Iinv detected by current sensor 430 with self-path current target value Iinv **.
- the control unit 420 performs the self-path current Iinv and the self-path current target value Iinv ** in step S02.
- the switching control signals S1 to S4 are generated based on the current deviation.
- the control unit 420 performs the self-path current Iinv and the self-path current target value Iinv in step S03.
- Switching control signals S1 to S4 are generated based on the current deviation from **.
- the own path current Iinv changes in the negative direction (the power purchase direction) (that is, the own path current Iinv decreases).
- the processing in steps S01 to S03 corresponds to the processing in step S200 shown in FIG.
- the control unit 420 acquires the battery current Ib (battery current detection information) from the current sensor 60 during the execution of the current control shown in S01 to S03. Then, control unit 420 determines whether or not battery current Ib is within the current range of power storage device 3. Specifically, in step S04, control unit 420 determines whether or not battery current Ib is greater than or equal to the lower limit value (eg, ⁇ 10 A) of the current range. When the battery current Ib is smaller than the lower limit (when NO is determined in step S04), the control unit 420 decreases the own path current target value Iinv ** by a predetermined amount ⁇ I1 in step S05.
- the lower limit value eg, ⁇ 10 A
- control unit 420 causes self-path current target value Iinv to decrease self-path current target value Iinv **. Adjust **.
- the power conversion operation is executed in accordance with the adjusted self-path current target value Iinv **, thereby reducing the self-path current Isel at the time of power sale while purchasing power.
- the self-path current Ibuy at increases.
- the self-path current target value Iinv ** is adjusted so that the electric power supplied from the power storage device 3 to the DC bus 1 is decreased at the time of both selling and buying power, thereby discharging the power storage device 3.
- the current Idc is within the current range.
- control unit 420 when battery current Ib is equal to or greater than the lower limit value of the current range (when YES is determined in step S04), control unit 420 further determines that battery current Ib is the upper limit value (10A) of the current range in step S06. ) Determine whether or not: When battery current Ib is larger than the upper limit value (when NO is determined in step S06), control unit 420 increases own path current target value Iinv ** by a predetermined amount ⁇ I1 in step S07.
- control unit 420 causes self-path current target value Iinv to increase self-path current target value Iinv **. Adjust **.
- the power conversion operation is executed in accordance with the adjusted self-path current target value Iinv **, thereby increasing the self-path current Isel at the time of power sale while purchasing power.
- the self-path current Ibuy at is reduced.
- the self-path current target value Iinv ** is adjusted so that the power supplied from the DC bus 1 to the power storage device 3 is reduced at the time of selling and buying power, thereby charging the power storage device 3.
- the current Ich falls within the current range.
- the own path current target value Iinv ** is increased or decreased by a predetermined amount ⁇ I1 so that the battery current Ib is within the current range.
- the predetermined amount ⁇ I1 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40.
- step S06 when the battery current Ib is equal to or lower than the upper limit value of the current range in step S06 (when YES is determined in step S06), that is, when the battery current Ib is within the current range of the power storage device 3, the control unit In step S08 to S11, 420 executes a return process for returning the own path current target value Iinv ** to the initial value Iinv *.
- control unit 420 determines whether or not the own path current target value Iinv ** is larger than the initial value Iinv * in step S08.
- control unit 420 decreases own path current target value Iinv ** by a predetermined amount ⁇ I2 in step S09.
- control unit 420 when the own path current target value Iinv ** is equal to or less than the initial value Iinv * (when NO is determined in step S08), the control unit 420 further performs step S10 to set the own path current target value Iinv ** to the initial value. It is determined whether it is smaller than Iinv *.
- control unit 420 increases own path current target value Iinv ** by a predetermined amount ⁇ I2 in step S11. Let The predetermined amount ⁇ I2 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40.
- the own path current target value Iinv ** when the own path current target value Iinv ** is equal to the initial value Iinv * (when NO is determined in step S10), the above-described return processing of the own path current target value Iinv ** is not performed.
- steps S08 to S11 is processing for returning the own path current target value Iinv ** to the initial value Iinv * while controlling the battery current Ib within the current range. Further, the processes in steps S04 to S11 correspond to the process in step S300 shown in FIG.
- control unit 420 adjusts self-path current target value Iinv ** so that battery current Ib is within the current range of power storage device 3 during execution of self-path current control.
- the current limitation in the power storage device 3 is limited. Electric power can be transferred to the DC bus 1 while complying.
- FIG. 9 is a flowchart for explaining a modified example of the processing in steps S200 and S300 in FIG.
- control unit 420 acquires battery current Ib (battery current detection information) from current sensor 60 in step S21.
- control unit 420 compares the obtained battery current Ib with the battery current Ib # stored in memory 520.
- This battery current Ib # corresponds to the battery current Ib acquired after adjustment of the own path current target value Inv ** in step S24 described later.
- control unit 420 When battery current Ib is equal to battery current Ib # (when YES is determined in step S22), control unit 420 performs steps S01 to S07 similar to FIG. 8 according to battery current Ib acquired from current sensor 60. The own path current target value Iinv ** is adjusted. Then, in step S24, control unit 420 obtains battery current Ib when current control is performed in accordance with adjusted self-path current target value Iinv ** and stores it in memory 520.
- control unit 420 changes own path current target value Iinv ** to initial value Iinv * in step S23. return. Then, control unit 420 adjusts own path current target value Iinv ** according to battery current Ib acquired from current sensor 60 through steps S01 to S07 similar to those in FIG. Further, in step S24, control unit 420 acquires battery current Ib when current control is performed in accordance with adjusted self-path current target value Iinv ** and stores it in memory 520.
- the adjusted self-path The current target value Iinv ** is returned to the initial value Iinv * and the self-path current target value Iinv ** is adjusted again. That is, the self-path current target value Iinv ** is returned to the initial value Iinv *, triggered by a change in the battery current Ib due to an external factor different from the self-path current control.
- the current range of power storage device 3 is not limited to the above example. That is, instead of the configuration in which the rated current (allowable charging / discharging current) of the power storage device 3 is set to the current range ( ⁇ 10A to 10A), 80% of the rated current is increased above the current range, for example, from the viewpoint of extending the battery life. You may set to a lower limit. Note that what percentage of the rated current is set to the upper and lower limit values can be arbitrarily selected according to the design concept considering the battery life.
- Some power storage devices have different allowable charge currents and allowable discharge currents. Therefore, the upper limit value (for example, 3A) and the lower limit value (for example, ⁇ 6A) are different depending on the specifications of the power storage device to be used. Even if it makes it, the same effect can be acquired.
- control target value generation unit 500 generates battery current target value Ib ** as a control target value of bidirectional DC / AC converter 40.
- the battery current target value Ib ** corresponds to the self-path current Iinv during execution of the battery current control, with the battery current target value Ib * determined according to the target value setting table of FIG. 3 as an initial value. This corresponds to the target battery current value after adjustment.
- switching element control signal generator 510 When switching element control signal generator 510 receives battery current target value Ib ** from control target value generator 500, switching element control signal generator 510 generates switching control signals S1 to S4 such that battery current Ib becomes battery current target value Ib **. Then, the bidirectional DC / AC converter 40 is controlled.
- the switching element control signal generation unit 510 generates an operation signal according to the deviation of the battery current Ib from the battery current target value Ib **, similarly to the self-path current control described above. Then, switching element control signal generation unit 510 generates a duty command that defines the on-duty of transistors Q1 to Q4 of bidirectional inverter 400 (FIG. 2) based on this operation signal. Are generated, the switching control signals S1 to S4 are generated.
- a predetermined current range in the bidirectional DC / AC converter 40 is stored instead of the predetermined current range in the power storage device 3.
- This predetermined current range corresponds to the range of current that can be passed through the bidirectional DC / AC converter 40 due to its specifications.
- This current range is determined based on the rated output of the bidirectional DC / AC converter 40, for example.
- 15 A is set as the upper and lower limit values of the current range. That is, the self-path current Iinv needs to be within the range of ⁇ 15A to 15A.
- Control target value generation unit 500 receives self-path current Iinv from current sensor 430, battery current Ib from current sensor 60, and battery remaining amount (SOC) of power storage device 3 from battery monitoring unit 6. Control target value generation unit 500 generates battery current target value Ib ** based on these input information and information stored in memory 520.
- FIG. 11 is a flowchart showing a control processing procedure for realizing battery current control of the power conversion device according to the present embodiment.
- the control process according to the flowchart shown in FIG. 11 is executed by the control unit 420 at regular intervals.
- Each step shown in FIG. 11 is realized by software processing and / or hardware processing by the control unit 420.
- control unit 420 sets current target value (battery current target value) Ib ** of battery current Ib in step S400.
- control unit 420 refers to a target value setting table (FIG. 3) stored in memory 520 to set battery current target value Ib * based on the date and time and the remaining battery level of power storage device 3.
- the process of step S400 corresponds to the function of the control target value generation unit 500.
- Control unit 420 sets battery current target value Ib * determined according to this target value setting table (FIG. 3) as an initial value of battery current target value Ib **. That is, initial value Ib * is a variable value that changes according to the date and time and the remaining battery level of power storage device 3.
- step S500 the control unit 420 generates switching control signals S1 to S4 so that the battery current Ib becomes the battery current target value Ib **, and controls the bidirectional inverter 400 (current control).
- step S600 when the control unit 420 acquires the self-path current Iinv (self-path current detection information) detected by the current sensor 430 during execution of the power conversion operation in the bidirectional inverter 400 in step S600, the acquired The battery current target value Ib ** is adjusted based on the own path current Iinv. Specifically, the control unit 420 compares the current range of the bidirectional DC / AC converter 40 stored in the memory 520 with the own path current Iinv. Then, the battery current target value Ib ** is adjusted based on the comparison result.
- the function of step S600 corresponds to the function of the control target value generation unit 500 shown in FIG.
- FIG. 12 is a flowchart for explaining the processing of steps S500 and S600 of FIG. 11 in more detail.
- control unit 420 compares battery current Ib detected by current sensor 60 with battery current target value Ib **.
- battery current Ib is smaller than battery current target value Ib ** (when YES is determined in step S31)
- control unit 420 performs current deviation between battery current Ib and battery current target value Ib ** in step S32.
- the switching control signals S1 to S4 based on the above are generated. By performing such control, the battery current Ib changes in the positive direction (charging direction) (that is, the battery current Ib increases).
- the control unit 420 determines whether the battery current Ib and the battery current target value Ib ** are set in step S33. Switching control signals S1 to S4 based on the current deviation are generated. By performing such control, the battery current Ib changes in the negative direction (discharge direction) (that is, the battery current Ib decreases).
- the processing in steps S31 to S33 corresponds to the processing in step S500 shown in FIG.
- the control unit 420 acquires the own path current Iinv (own path current detection information) from the current sensor 430 during the execution of the current control shown in S31 to S33. Then, the control unit 420 determines whether or not the self-path current Iinv is within the current range of the bidirectional DC / AC converter 40. Specifically, in step S34, control unit 420 determines whether or not self-path current Iinv is greater than or equal to the lower limit value (eg, ⁇ 15 A) of the current range. When the self-path current Iinv is smaller than the lower limit (when NO is determined in step S34), the control unit 420 decreases the battery current target value Ib ** by a predetermined amount ⁇ I3 in step S35.
- the lower limit value eg, ⁇ 15 A
- control unit 420 decreases battery current target value Ib **.
- the battery current target value Ib ** is adjusted so that Then, by executing the power conversion operation in bidirectional DC / AC converter 40 according to adjusted battery current target value Ib **, battery current (charging current) Ich at the time of charging is reduced in power storage device 3.
- the battery current (discharge current) Idc during discharge increases.
- the battery current target value Ib ** is such that the power supplied from the DC bus 1 to the power storage device 3 during charging decreases while the power supplied from the power storage device 3 to the DC bus 1 increases during discharging. Is adjusted so that the self-path current Iinv at the time of power purchase falls within the current range.
- control unit 420 when the own path current Iinv is equal to or greater than the lower limit value of the current range (when YES is determined in step S34), the control unit 420 further causes the own path current Iinv to exceed the upper limit value of the current range in step S36. (15A) It is determined whether or not. When own path current Iinv is larger than the upper limit value (NO determination in step S36), control unit 420 increases battery current target value Ib ** by a predetermined amount ⁇ I3 in step S37.
- control unit 420 increases battery current target value Ib **.
- the battery current target value Ib ** is adjusted so that Then, by executing the power conversion operation in bidirectional DC / AC converter 40 according to the adjusted battery current target value Ib **, battery current (charging current) Ich during charging increases in power storage device 3.
- the battery current (discharge current) Idc during discharge decreases.
- the battery current target value Ib ** is such that the power supplied from the DC bus 1 to the power storage device 3 during charging increases while the power supplied from the power storage device 3 to the DC bus 1 decreases during discharging. Is adjusted so that the self-path current Iinv at the time of power sale falls within the current range.
- the battery current target value Ib ** is set to a predetermined amount so that the own path current Iinv is within the current range. Increase or decrease by ⁇ I3.
- the predetermined amount ⁇ I3 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40.
- step S36 when the own path current Iinv is equal to or lower than the upper limit value of the current range in step S36 (when YES is determined in step S36), that is, the own path current Iinv falls within the current range of the bidirectional DC / AC converter 30. If so, the control unit 420 executes a return process for returning the battery current target value Ib ** to the initial value Ib *.
- control unit 420 determines whether or not battery current target value Ib ** is greater than initial value Ib *.
- control unit 420 decreases battery current target value Ib ** by a predetermined amount ⁇ I4 in step S39.
- control unit 420 when battery current target value Ib ** is equal to or smaller than initial value Ib * (when NO is determined in step S38), control unit 420 further performs battery current target value Ib ** to initial value Ib * in step S40. It is determined whether it is smaller. When battery current target value Ib ** is smaller than initial value Ib * (when YES is determined in step S40), control unit 420 increases battery current target value Ib ** by a predetermined amount ⁇ I4 in step S41. The predetermined amount ⁇ I4 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40. On the other hand, when battery current target value Ib ** is equal to initial value Ib * (when NO is determined in step S40), the above-described return processing of battery current target value Ib ** is not performed.
- the processing shown in the above steps S38 to S41 is processing for returning the battery current target value Ib ** to the initial value Ib * while keeping the self-path current Iinv within the current range. Further, the processing in steps S34 to S41 corresponds to the processing in step S600 shown in FIG.
- control unit 420 adjusts battery current target value Ib ** so that self-path current Iinv is within the current range of bidirectional DC / AC converter 40 during execution of battery current control. .
- the power exchanged between the DC bus 1 and the bidirectional DC / AC converter 40 fluctuates in response to fluctuations in the amount of power generated by the photovoltaic power generation system 2 and / or the amount of power consumed by the DC load 5. Even in this case, power can be transferred to the DC bus 1 while observing the current limitation of the bidirectional DC / AC converter 40.
- FIG. 13 is a flowchart for explaining a modified example of the processing of steps S500 and S600 of FIG.
- control unit 420 acquires own path current Iinv (own path current detection information) from current sensor 430 in step S51. Then, in step S52, control unit 420 compares acquired self path current Iinv with self path current Iinv # stored in memory 520. This own path current Iinv # corresponds to the own path current Iinv acquired after adjustment of the battery current target value Ib ** in step S54 described later.
- control unit 420 When self-path current Iinv is equal to self-path current Iinv # (when YES is determined in step S52), control unit 420 performs self-path current Iinv acquired from current sensor 430 in steps S31 to S37 similar to FIG. The battery current target value Ib ** is adjusted according to the above. Then, in step S54, control unit 420 obtains self-path current Iinv when current control is performed according to the adjusted battery current target value Ib **, and stores it in memory 520.
- the current range of the bidirectional DC / AC converter 40 is not limited to the above example. That is, instead of the configuration in which the rated output of the bidirectional DC / AC converter 40 is set to the current range, for example, 80% of the rated output may be set to the upper and lower limit values of the current range. It should be noted that what percentage of the rated output is set as the upper and lower limit values can be arbitrarily selected according to the design concept in consideration of the component life. Further, the same effect can be obtained even if the upper limit value and the lower limit value are made different according to the specifications of the bidirectional DC / AC converter to be used.
- DC system configuration example In the above description, as an example of the DC system, the configuration in which the photovoltaic power generation system 2, the power storage device 3, the system power system 4, and the DC load 5 are connected to the DC bus 1 has been described. However, the application of the present invention is not limited to such a DC system. Specifically, the present invention can be applied as long as the power storage device 3 and the grid power system 4 are connected to at least the DC bus 1. Therefore, for example, as shown in FIG. 14, a DC system configured by connecting the photovoltaic power generation system 2, the power storage device 3, and the system power system 4 to the DC bus 1, or as shown in FIG. 15, The present invention is also applicable to a DC system configured by connecting the power storage device 3 and the system power system 4.
- the solar power generation system has been described as an example of the distributed power supply device, a wind power generation device, a fuel cell, and the like may be used.
- the bidirectional DC / AC converter that performs bidirectional power conversion between the DC bus and the system power has been described as an example of the power conversion device.
- DC / AC converter for converting AC power into AC power and supplying it to system power and AC / DC converter for converting AC power received from system power into a DC bus and supplying it to the DC bus
- the present invention can also be applied to a conversion device.
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Abstract
In a direct-current system in which an electrical storage device (3) is directly coupled to a direct-current bus (1), a bidirectional DC/AC converter (40) is equipped with: a power conversion unit that converts power in a bidirectional manner between the direct-current bus (1) and system power (42); a local-path current detection unit that detects local-path current that passes through the power conversion unit; a charging/discharging current detection unit that detects charging/discharging current of the electrical storage device (3); and a control unit that controls the power conversion unit. The control unit includes: a power conversion control means for controlling power conversion in the power conversion unit in such a way that the local-path current assumes a control target value; and an adjustment means for adjusting the control target value during execution of the power conversion control means, in such a way that the detection value for the charging/discharging current stays within a predetermined current range.
Description
この発明は、電力変換装置に関し、より特定的には、直流電力を給電する直流システムに適用される電力変換装置の電力変換制御に関する。
The present invention relates to a power converter, and more particularly to power conversion control of a power converter applied to a DC system that supplies DC power.
近年、太陽電池、風力発電装置および燃料電池のような分散電源装置が普及し始めている。現状では、分散電源装置が発電した直流電力を交流電力に変換し、さらに、その交流電力を、電力を消費する機器において直流電力に変換して使用する。このように、直流-交流変換および交流-直流変換が行なわれるため、その電力変換のたびに電力損失が生じる。そこで、分散電源装置が発電する直流電力を交流電力に変換することなく、直流電力のまま送電して機器で使用することにより、変換損失を低減させる直流システムが提案されている。
In recent years, distributed power supply devices such as solar cells, wind power generators and fuel cells have begun to spread. At present, the DC power generated by the distributed power supply device is converted into AC power, and the AC power is converted into DC power and used in a device that consumes the power. Thus, since DC-AC conversion and AC-DC conversion are performed, a power loss occurs at each power conversion. Therefore, a DC system has been proposed that reduces conversion loss by transmitting DC power as it is and using it in equipment without converting the DC power generated by the distributed power supply into AC power.
このような直流システムとして、たとえば特開2005-224009号公報(特許文献1)には、直流バスに接続された複数の電源ユニットの各々が電流制御部を有しており、該電流制御部が、対応する電源ユニットに入出力する電流に従って自律的に直流電圧指令値または直流電圧の制御性を変更する機能を備える構成が開示されている。この特許文献1に記載の直流システムは、複数の分散電源が自律的に協調運転するとともに、装置容量に依存せずに、簡単に電源ユニットを追加することを可能としている。
As such a DC system, for example, in JP 2005-224209 A (Patent Document 1), each of a plurality of power supply units connected to a DC bus has a current control unit, and the current control unit A configuration having a function of autonomously changing a DC voltage command value or DC voltage controllability in accordance with a current input / output to / from a corresponding power supply unit is disclosed. The DC system described in Patent Document 1 allows a plurality of distributed power supplies to autonomously operate in a coordinated manner and easily add a power supply unit without depending on the device capacity.
しかしながら、上記の特許文献1に記載の直流システムにおいては、複数の分散電源を自律的に協調運転することが可能になる一方で、各電源ユニットにおける入出力電流が変化すると、この変化に応じて直流バスの電圧の制御目標値が変更されるため、システム全体の制御が複雑化するという問題があった。
However, in the DC system described in Patent Document 1 described above, a plurality of distributed power supplies can be autonomously operated in a coordinated manner. On the other hand, when the input / output current in each power supply unit changes, Since the control target value of the voltage of the DC bus is changed, there is a problem that the control of the entire system becomes complicated.
また、電源ユニットごとに電力変換器を設ける必要あるため、該電力変換器における変換損失が増大するとともに、システムのコストアップが発生するという問題があった。
Further, since it is necessary to provide a power converter for each power supply unit, there is a problem that conversion loss in the power converter increases and the cost of the system increases.
このような課題を解決するためには、蓄電池のような電圧安定化能力の高い電圧源を電力変換器を介さず直流バスに直結することによって、直流バスの電圧を無制御で安定化させることが可能である。
In order to solve such a problem, the voltage of the DC bus is stabilized without control by directly connecting a voltage source having a high voltage stabilizing capability such as a storage battery to the DC bus without using a power converter. Is possible.
しかしながら、上述した蓄電池を直流バスに直結させる構成においては、直流バスと蓄電池との間で直接的に電力のやり取りが行なわれるため、分散電源および/または系統電力と直流バスとの間で授受される電力の変動の影響を直接受けて、蓄電池に対して入出力される充放電電流に変動を生じさせやすい。そのため、蓄電池の充放電電流が予め定められた電流範囲を逸脱してしまう可能性がある。
However, in the above-described configuration in which the storage battery is directly connected to the DC bus, power is directly exchanged between the DC bus and the storage battery, so that the power is exchanged between the distributed power source and / or the system power and the DC bus. Directly affected by fluctuations in power, the charge / discharge current input / output to / from the storage battery tends to fluctuate. Therefore, the charge / discharge current of the storage battery may deviate from a predetermined current range.
蓄電池には、通常、その仕様に応じて、蓄電池に流すことのできる「許容充電電流」および「許容放電電流」が定められている。この許容充電電流および許容放電電流を超える充放電電流が蓄電池に流れると、蓄電池の劣化が進行しやすい。よって、蓄電池の充放電電流を許容充電電流および許容放電電流を超えないように制御する必要がある。なお、この許容充電電流および許容放電電流は、定格電流とも記載される場合がある。
A storage battery normally has “allowable charging current” and “allowable discharge current” that can be passed through the storage battery according to its specifications. When a charge / discharge current exceeding the allowable charge current and the allowable discharge current flows to the storage battery, the storage battery is likely to deteriorate. Therefore, it is necessary to control the charging / discharging current of the storage battery so as not to exceed the allowable charging current and the allowable discharging current. Note that the allowable charging current and the allowable discharging current may be described as a rated current.
さらに、直流バスに対して授受される電力の変動の影響は、直流バスと系統電力との間で電力変換を行なう電力変換装置にも及ぶ。直流バスに対して授受される電力が変動した場合には、直流バスと電力変換装置との間の電力収支のバランスが崩れることにより、電力変換装置の定格出力を超える電力が出力される可能性がある。
Furthermore, the influence of fluctuations in power transferred to and from the DC bus extends to a power conversion device that performs power conversion between the DC bus and the system power. If the power sent to or received from the DC bus fluctuates, the balance of power balance between the DC bus and the power converter may be disrupted, possibly resulting in power exceeding the rated output of the power converter. There is.
それゆえ、この発明はかかる課題を解決するためになされたものであり、その目的は、直流バスに電力変換器を介さず蓄電装置を直結した直流システムにおいて、蓄電装置を保護することである。
Therefore, the present invention has been made to solve such a problem, and an object thereof is to protect the power storage device in a DC system in which the power storage device is directly connected to the DC bus without using a power converter.
この発明の別の目的は、直流バスに電力変換器を介さず蓄電装置を直結した直流システムにおいて、直流バスおよび系統電力の間で電力変換する電力変換装置を保護することである。
Another object of the present invention is to protect a power converter that converts power between the DC bus and system power in a DC system in which a power storage device is directly connected to the DC bus without a power converter.
この発明のある局面では、電力変換装置は、蓄電装置および系統電力の間に配設された直流バスに接続される。電力換装置は、直流バスおよび系統電力の間で電力変換する電力変換部と、電力変換部を流れる自経路電流を検出する自経路電流検出部と、蓄電装置の充放電電流を取得する充放電電流取得部と、電力変換部を制御する制御部とを備える。制御部は、自経路電流が制御目標値になるように電力変換部における電力変換を制御するための電力変換制御手段と、電力変換制御手段の実行中に、取得された充放電電流が所定の電流範囲に収まるように、制御目標値を調整するための調整手段とを含む。
In one aspect of the present invention, the power converter is connected to a DC bus disposed between the power storage device and the system power. The power conversion device includes a power conversion unit that converts power between a DC bus and system power, a self-path current detection unit that detects a self-path current flowing through the power conversion unit, and a charge / discharge that acquires a charge / discharge current of the power storage device A current acquisition unit and a control unit that controls the power conversion unit are provided. The control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the self-path current becomes a control target value, and the acquired charge / discharge current is predetermined during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
好ましくは、調整手段は、予め定められた制御目標値を初期値に設定して電力変換制御手段を実行したときの充放電電流が所定の電流範囲を超えているときに、充放電電流に応じて制御目標値を変更するための変更手段と、変更後の制御目標値を用いた電力変換制御手段の実行中に、充放電電流を所定の電流範囲に制御しつつ、制御目標値を初期値に戻すための復帰手段とを含む。
Preferably, the adjustment means responds to the charge / discharge current when the charge / discharge current when the power conversion control means is executed with the predetermined control target value set to an initial value exceeds a predetermined current range. During the execution of the changing means for changing the control target value and the power conversion control means using the changed control target value, the control target value is set to the initial value while controlling the charging / discharging current within a predetermined current range. And return means for returning to.
好ましくは、調整手段は、予め定められた制御目標値を初期値に設定して電力変換制御手段を実行したときの充放電電流が所定の電流範囲を超えているときに、充放電電流に応じて制御目標値を変更するための変更手段と、変更後の制御目標値を用いた電力変換制御手段の実行中に、充放電電流が所定の電流範囲に収まっている状態で、充放電電流が変化したときには、制御目標値を初期値に戻すための復帰手段とを含む。
Preferably, the adjustment means responds to the charge / discharge current when the charge / discharge current when the power conversion control means is executed with the predetermined control target value set to an initial value exceeds a predetermined current range. During the execution of the change means for changing the control target value and the power conversion control means using the changed control target value, the charge / discharge current is in a state where the charge / discharge current is within a predetermined current range. Returning means for returning the control target value to the initial value when it has changed is included.
この発明の別の局面では、電力変換装置は、蓄電装置および系統電力の間に配設された直流バスに接続される。電力変換装置は、直流バスおよび系統電力の間で電力変換する電力変換部と、電力変換部を流れる自経路電流を検出する自経路電流検出部と、蓄電装置の充放電電流を取得する充放電電流取得部と、電力変換部を制御する制御部とを備える。制御部は、充放電電流が制御目標値になるように電力変換部における電力変換を制御するための電力変換制御手段と、電力変換制御手段の実行中に、自経路電流の検出値が所定の電流範囲に収まるように、制御目標値を調整するための調整手段とを含む。
In another aspect of the present invention, the power converter is connected to a DC bus disposed between the power storage device and the system power. The power converter includes a power converter that converts power between the DC bus and the grid power, a self-path current detector that detects a self-path current that flows through the power converter, and a charge / discharge that acquires a charge / discharge current of the power storage device A current acquisition unit and a control unit that controls the power conversion unit are provided. The control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the charge / discharge current becomes a control target value, and a detected value of the own path current is predetermined during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
好ましくは、調整手段は、予め定められた制御目標値を初期値に設定して電力変換制御手段を実行したときの自経路電流の検出値が所定の電流範囲を超えているときには、自経路電流の検出値に応じて制御目標値を変更するための変更手段と、変更後の制御目標値を用いた電力変換制御手段の実行中に、自経路電電流の検出値を所定の電流範囲に制御しつつ、制御目標値を初期値に戻すための復帰手段とを含む。
Preferably, the adjusting means sets the predetermined control target value as an initial value, and when the detected value of the self-path current when the power conversion control means is executed exceeds a predetermined current range, the self-path current During the execution of the change means for changing the control target value according to the detected value and the power conversion control means using the changed control target value, the detected value of the own path current is controlled within a predetermined current range. However, a return means for returning the control target value to the initial value is included.
好ましくは、調整手段は、予め定められた制御目標値を初期値に設定して電力変換制御手段を実行したときの自経路電流の検出値が所定の電流範囲を超えているときには、自経路電流の検出値に応じて制御目標値を変更するための変更手段と、変更後の制御目標値を用いた電力変換制御手段の実行中に、自経路電流の検出値が所定の電流範囲に収まっている状態で、自経路電流の検出値が変化したときには、制御目標値を初期値に戻すための復帰手段とを含む。
Preferably, the adjusting means sets the predetermined control target value as an initial value, and when the detected value of the self-path current when the power conversion control means is executed exceeds a predetermined current range, the self-path current During the execution of the changing means for changing the control target value according to the detected value and the power conversion control means using the changed control target value, the detected value of the own path current falls within a predetermined current range. And a return means for returning the control target value to the initial value when the detected value of the self-path current changes.
この発明の別の局面によれば、直流システムは、直流バスと、電源電圧を直流バスに出力する蓄電装置と、直流バスおよび系統電力の間に接続される電力変換装置と、電力変換装置を流れる自経路電流を検出する自経路電流検出部と、蓄電装置の充放電電流を検出する充放電電流検出部とを備える。電力変換装置は、直流バスおよび系統電力の間で電力変換する電力変換部と、電力変換部を制御する制御部とを含む。制御部は、自経路電流が制御目標値になるように電力変換部における電力変換を制御するための電力変換制御手段と、電力変換制御手段の実行中に、充放電電流の検出値が所定の電流範囲に収まるように、制御目標値を調整するための調整手段とを含む。
According to another aspect of the present invention, a DC system includes a DC bus, a power storage device that outputs a power supply voltage to the DC bus, a power converter connected between the DC bus and the system power, and a power converter. A self-path current detection unit that detects a flowing self-path current and a charge / discharge current detection unit that detects a charge / discharge current of the power storage device. The power conversion device includes a power conversion unit that converts power between a DC bus and system power, and a control unit that controls the power conversion unit. The control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the self-path current becomes a control target value, and a detection value of the charge / discharge current is predetermined during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
この発明の別の局面によれば、直流システムは、直流バスと、電源電圧を直流バスに出力する蓄電装置と、直流バスおよび系統電力の間に接続される電力変換装置と、電力変換装置を流れる自経路電流を検出する自経路電流検出部と、蓄電装置の充放電電流を検出する充放電電流検出部とを備える。電力変換装置は、直流バスおよび系統電力の間で電力変換する電力変換部と、電力変換部を制御する制御部とを含む。制御部は、充放電電流が制御目標値となるように電力変換部における電力変換を制御するための電力変換制御手段と、電力変換制御手段の実行中に、自経路電流の検出値が所定の電流範囲に収まるように、制御目標値を調整するための調整手段とを含む。
According to another aspect of the present invention, a DC system includes a DC bus, a power storage device that outputs a power supply voltage to the DC bus, a power converter connected between the DC bus and the system power, and a power converter. A self-path current detection unit that detects a flowing self-path current and a charge / discharge current detection unit that detects a charge / discharge current of the power storage device. The power conversion device includes a power conversion unit that converts power between a DC bus and system power, and a control unit that controls the power conversion unit. The control unit includes a power conversion control unit for controlling power conversion in the power conversion unit so that the charge / discharge current becomes a control target value, and a detection value of the own path current is a predetermined value during execution of the power conversion control unit. Adjusting means for adjusting the control target value so as to be within the current range.
この発明によれば、直流バスに電力変換器を介さず蓄電部を直結した直流システムにおいて、蓄電装置および電力変換装置を保護することができる。
According to the present invention, the power storage device and the power conversion device can be protected in the DC system in which the power storage unit is directly connected to the DC bus without the power converter.
以下、本発明の実施の形態について、図面を参照しながら詳細に説明する。なお、図中の同一または相当する部分には同一符号を付してその説明は繰返さない。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.
(直流システムの構成)
図1は、この発明の実施の形態に従う電力変換装置が適用される直流システムの全体の構成を概略的に示す図である。 (Configuration of DC system)
FIG. 1 schematically shows an overall configuration of a DC system to which a power conversion device according to an embodiment of the present invention is applied.
図1は、この発明の実施の形態に従う電力変換装置が適用される直流システムの全体の構成を概略的に示す図である。 (Configuration of DC system)
FIG. 1 schematically shows an overall configuration of a DC system to which a power conversion device according to an embodiment of the present invention is applied.
図1を参照して、本実施の形態に従う直流システムは、直流バス1と、太陽光発電システム2と、蓄電装置3と、系統電力システム4と、直流負荷5と、電池監視ユニット6とを備える。
Referring to FIG. 1, the DC system according to the present embodiment includes a DC bus 1, a photovoltaic power generation system 2, a power storage device 3, a grid power system 4, a DC load 5, and a battery monitoring unit 6. Prepare.
直流バス1は、直流負荷5に直流電力を供給する。直流負荷5は、一例として、家庭で使用される空調機、冷蔵庫、洗濯機、テレビ、照明装置またはパーソナルコンピュータのような電気機器である。あるいは、オフィスで使用されるコンピュータ、複写機またはファクシミリのような電気機器や、または、店舗で使用されるショーケースまたは照明装置のような電気機器であってもよい。直流バス1には、太陽光発電システム2、蓄電装置3および系統電力システム4が接続されている。
DC bus 1 supplies DC power to DC load 5. The DC load 5 is, for example, an electric device such as an air conditioner, a refrigerator, a washing machine, a television, a lighting device, or a personal computer used at home. Alternatively, it may be an electric device such as a computer, a copier or a facsimile used in an office, or an electric device such as a showcase or a lighting device used in a store. A solar power generation system 2, a power storage device 3, and a system power system 4 are connected to the DC bus 1.
なお、本実施の形態に従う直流システムにおいては、直流バス1、太陽光発電システム2、蓄電装置3、系統電力システム4および直流負荷5をそれぞれ1個ずつ備える場合について説明するが、これらの個数には制限がなく、1個でも複数個であってもよい。
In the DC system according to the present embodiment, a case will be described in which one DC bus 1, a photovoltaic power generation system 2, a power storage device 3, a grid power system 4, and one DC load 5 are provided. There is no limitation, and one or more may be used.
(蓄電装置の構成)
蓄電装置3は、一例として、リチウムイオン二次電池などの充放電可能に構成された二次電などからなる。蓄電装置3は、複数の電池セルを直列接続して構成されており、一例として、定格電圧400Vおよび定格容量4kWhを有している。 (Configuration of power storage device)
The power storage device 3 includes, for example, a secondary battery configured to be chargeable / dischargeable, such as a lithium ion secondary battery. The power storage device 3 is configured by connecting a plurality of battery cells in series. As an example, the power storage device 3 has a rated voltage of 400 V and a rated capacity of 4 kWh.
蓄電装置3は、一例として、リチウムイオン二次電池などの充放電可能に構成された二次電などからなる。蓄電装置3は、複数の電池セルを直列接続して構成されており、一例として、定格電圧400Vおよび定格容量4kWhを有している。 (Configuration of power storage device)
The power storage device 3 includes, for example, a secondary battery configured to be chargeable / dischargeable, such as a lithium ion secondary battery. The power storage device 3 is configured by connecting a plurality of battery cells in series. As an example, the power storage device 3 has a rated voltage of 400 V and a rated capacity of 4 kWh.
蓄電装置3は、直流バス1に「直結」されており、直流バス1との間で直流電力の授受を行なう。ここで、「直結」とは、直流バス1と蓄電装置3との間に、DC/DC変換器のような電力変換器が介在していないことを意味する。したがって、直流バス1の電圧は、蓄電装置3の電源電圧とほぼ等しくなる。このように蓄電装置3を直流バス1に直結する構成としたことにより、蓄電装置3が有する高い電圧安定化能力を活かして、急激な負荷変動による直流バス1の電圧変動を抑制することが可能となる。
The power storage device 3 is “directly connected” to the DC bus 1, and exchanges DC power with the DC bus 1. Here, “directly connected” means that a power converter such as a DC / DC converter is not interposed between the DC bus 1 and the power storage device 3. Therefore, the voltage of DC bus 1 is substantially equal to the power supply voltage of power storage device 3. By adopting a configuration in which the power storage device 3 is directly connected to the DC bus 1 in this way, it is possible to suppress voltage fluctuations of the DC bus 1 due to sudden load fluctuations by utilizing the high voltage stabilization capability of the power storage device 3. It becomes.
電池監視ユニット6は、蓄電装置3に設けられた電流センサ60、電圧センサ62および温度センサ64の出力に基づいて、蓄電装置3の状態値を検出する。具体的には、電流センサ60は、直流バス1に介挿され、蓄電装置3に対して入出力される充放電電流Ibを検出し、その検出値を電池監視ユニット6へ出力する。電圧センサ62は、蓄電装置3の充放電電圧Vbを検出し、その検出値を電池監視ユニット6へ出力する。温度センサ64は、蓄電装置3の温度Tbを検出し、その検出値を電池監視ユニット6へ出力する。上述のように、蓄電装置3として代表的には二次電池が用いられるため、蓄電装置3の電流Ib、電圧Vbおよび温度Tbについて、以下では、電池電流Ib、電池電圧Vbおよび電池温度Tbとも称する。
Battery monitoring unit 6 detects the state value of power storage device 3 based on the outputs of current sensor 60, voltage sensor 62 and temperature sensor 64 provided in power storage device 3. Specifically, current sensor 60 detects charge / discharge current Ib that is inserted in DC bus 1 and input / output to / from power storage device 3, and outputs the detected value to battery monitoring unit 6. Voltage sensor 62 detects charge / discharge voltage Vb of power storage device 3 and outputs the detected value to battery monitoring unit 6. Temperature sensor 64 detects temperature Tb of power storage device 3 and outputs the detected value to battery monitoring unit 6. As described above, since a secondary battery is typically used as power storage device 3, current Ib, voltage Vb, and temperature Tb of power storage device 3 will be described below as battery current Ib, battery voltage Vb, and battery temperature Tb. Called.
電流センサ60は、蓄電装置3への充電電流Ichを、正値の電池電流Ibとして検出し、蓄電装置3からの放電電流Idcを、負値の電池電流Ibとして検出する。電流センサ60は「充放電電流検出部」に対応する。
Current sensor 60 detects charging current Ich to power storage device 3 as positive battery current Ib, and detects discharge current Idc from power storage device 3 as negative battery current Ib. The current sensor 60 corresponds to a “charge / discharge current detector”.
なお、本実施の形態による直流システムでは、直流バス1に蓄電装置3を直結するとともに、後述するように、双方向DC/AC変換器40をフルブリッジインバータにより構成したことにより、双方向DC/AC変換器40の電力変換動作によって電池電流Ibには系統電力42の周波数に応じた周波数の交流成分が重畳される。電流センサ60は、この電池電流Ibの平均値を検出する。あるいは、電池電流Ibのピーク値を検出してもよい。
In the direct current system according to the present embodiment, power storage device 3 is directly connected to direct current bus 1, and bidirectional DC / AC converter 40 is configured by a full bridge inverter, as will be described later. By the power conversion operation of the AC converter 40, an AC component having a frequency corresponding to the frequency of the system power 42 is superimposed on the battery current Ib. The current sensor 60 detects the average value of the battery current Ib. Alternatively, the peak value of the battery current Ib may be detected.
電池監視ユニット6は、電流センサ60からの電池電流Ibの検出値、電圧センサ62からの電池電圧Vbの検出値および温度センサ64からの電池温度Tbの検出値に基づいて、蓄電装置3の電池残量(SOC:State of Charge)を推定する。SOCは、満充電容量に対する現在の残容量を百分率で示したものである。たとえば、電池監視ユニット6は、蓄電装置3の開放電圧(OCV:Open Circuit Voltage)とSOCとの関係に基づいてSOC推定値を算出する。あるいは、蓄電装置3の充放電量の積算値に基づいてSOC推定値を順次演算してもよい。充放電量の積算値は、電池電流Ibおよび電池電圧Vbの積(電力)を時間的に積分することで得られる。以下では、電池電流Ib、電池電圧Vb、電池温度Tb、およびSOC推定値を包括的に「電池データ」とも総称する。
Based on the detected value of the battery current Ib from the current sensor 60, the detected value of the battery voltage Vb from the voltage sensor 62, and the detected value of the battery temperature Tb from the temperature sensor 64, the battery monitoring unit 6 Estimate the remaining amount (SOC: State of Charge). The SOC is a percentage of the current remaining capacity with respect to the full charge capacity. For example, the battery monitoring unit 6 calculates the estimated SOC value based on the relationship between the open circuit voltage (OCV) of the power storage device 3 and the SOC. Alternatively, the estimated SOC value may be calculated sequentially based on the integrated value of the charge / discharge amount of power storage device 3. The integrated value of the charge / discharge amount can be obtained by temporally integrating the product (electric power) of the battery current Ib and the battery voltage Vb. Hereinafter, the battery current Ib, the battery voltage Vb, the battery temperature Tb, and the estimated SOC value are collectively referred to as “battery data”.
(太陽光発電システムの構成)
太陽光発電システム2は、太陽電池20と、DC/DC変換器22とを含む。太陽電池20は、結晶型太陽電池、多結晶型太陽電池または薄膜型太陽電池などで構成される。DC/DC変換器22は、太陽電池20と直流バス1と間に配置されており、太陽電池20から受ける直流電力を電圧変換して直流バス1へ供給する。 (Configuration of solar power generation system)
The solarpower generation system 2 includes a solar cell 20 and a DC / DC converter 22. The solar cell 20 is composed of a crystalline solar cell, a polycrystalline solar cell, a thin film solar cell, or the like. The DC / DC converter 22 is disposed between the solar cell 20 and the DC bus 1, converts the DC power received from the solar cell 20 into a voltage, and supplies it to the DC bus 1.
太陽光発電システム2は、太陽電池20と、DC/DC変換器22とを含む。太陽電池20は、結晶型太陽電池、多結晶型太陽電池または薄膜型太陽電池などで構成される。DC/DC変換器22は、太陽電池20と直流バス1と間に配置されており、太陽電池20から受ける直流電力を電圧変換して直流バス1へ供給する。 (Configuration of solar power generation system)
The solar
DC/DC変換器22における電圧変換動作は、太陽電池20の出力電圧と、直流バス1の電圧(正母線PLおよび負母線NLの間の線間電圧)とに応じて、図示しない制御部からのスイッチング指令に従って制御される。具体的には、直流バス1の電圧が420V(満充電状態のときの蓄電装置3の電源電圧に相当)よりも低いときには、DC/DC変換器22は、太陽電池20を最大電力点追従(MPPT)制御する。そして、直流バス1の電圧が420Vに到達すると、DC/DC変換器22は、最大電力点制御から直流バス1の電圧を420Vに維持するための制御に切替えて太陽電池20を制御する。
The voltage conversion operation in the DC / DC converter 22 is performed by a control unit (not shown) according to the output voltage of the solar battery 20 and the voltage of the DC bus 1 (the line voltage between the positive bus PL and the negative bus NL). It is controlled according to the switching command. Specifically, when the voltage of DC bus 1 is lower than 420 V (corresponding to the power supply voltage of power storage device 3 when fully charged), DC / DC converter 22 causes solar cell 20 to follow the maximum power point ( MPPT) control. When the voltage of the DC bus 1 reaches 420V, the DC / DC converter 22 controls the solar battery 20 by switching from the maximum power point control to the control for maintaining the voltage of the DC bus 1 at 420V.
(系統電力システムの構成)
図1に示す構成において、系統電力システム4は、直流バス1との間で直流電力の授受を行なう。系統電力システム4は、双方向DC/AC変換器40と、系統電力42とを含む。 (System power system configuration)
In the configuration shown in FIG. 1, system power system 4 exchanges DC power withDC bus 1. The grid power system 4 includes a bidirectional DC / AC converter 40 and a grid power 42.
図1に示す構成において、系統電力システム4は、直流バス1との間で直流電力の授受を行なう。系統電力システム4は、双方向DC/AC変換器40と、系統電力42とを含む。 (System power system configuration)
In the configuration shown in FIG. 1, system power system 4 exchanges DC power with
系統電力42は、電力会社等から受電する電力(たとえば、AC200Vとする)である。系統電力42は、例えば、単相3相式の商用交流電力系統から供給される。単相3線式商用交流電力系統は、中性線が抵抗を介して接地されており、中性線以外の2線(R相線RLおよびT相線TL)を使用してAC200Vを供給する。
The grid power 42 is power received from an electric power company or the like (for example, AC 200V). The system power 42 is supplied from, for example, a single-phase three-phase commercial AC power system. In the single-phase three-wire commercial AC power system, the neutral wire is grounded via a resistor, and AC200V is supplied using two wires (R-phase wire RL and T-phase wire TL) other than the neutral wire. .
双方向DC/AC変換器40は、直流バス1および系統電力42の間に接続される。双方向DC/AC変換器40は、直流バス1から受ける直流電力を交流電力に変換して系統電力42へ供給する。また、双方向DC/AC変換器40は、系統電力42から受ける交流電力を直流電力に変換して直流バス1へ供給する。本実施の形態に従う直流システムにおいては、双方向DC/AC変換器40を介して電力会社等から系統電力を買う(買電)とともに、双方向DC/AC変換器40を介して余剰電力を電力会社等に売る(売電)することを可能に構成されている。
The bidirectional DC / AC converter 40 is connected between the DC bus 1 and the system power 42. Bidirectional DC / AC converter 40 converts the DC power received from DC bus 1 into AC power and supplies it to system power 42. Further, the bidirectional DC / AC converter 40 converts AC power received from the system power 42 into DC power and supplies it to the DC bus 1. In the DC system according to the present embodiment, system power is purchased from an electric power company or the like (power purchase) via bidirectional DC / AC converter 40, and surplus power is supplied via bidirectional DC / AC converter 40. It is configured to be able to sell (power sale) to companies.
なお、図1では、双方向DC/AC変換器40に流れる電流(以下、「自経路電流」とも称する)Iinvについて、買電時の自経路電流をIbuy、売電時の自経路電流をIsellと表記する。また、直流負荷5に供給される電流をIloadと表記し、太陽光発電システム2から直流バス1に供給される電流をIpvと表記する。買電時においては、電流Ipvおよび電流Ibuyの和から電流Iloadを差し引いた電流が、蓄電装置3の充電電流Ichとなる。また、売電時においては、電流Ipvおよび蓄電装置3の放電電流Idcの和から電流Iloadを差し引いた電流が、電流Isellとなる。電流IsellおよびIbuyをどのような値にするかについては、直流システムの使用者または管理者が自在に設定することができる。
In FIG. 1, for the current flowing through the bidirectional DC / AC converter 40 (hereinafter also referred to as “self-path current”) Iinv, the self-path current during power purchase is Ibuy, and the self-path current during power sale is Icell. Is written. Further, the current supplied to the DC load 5 is expressed as Iload, and the current supplied from the solar power generation system 2 to the DC bus 1 is expressed as Ipv. At the time of power purchase, a current obtained by subtracting the current Iload from the sum of the current Ipv and the current Ibuy becomes the charging current Ich of the power storage device 3. At the time of power sale, a current obtained by subtracting current Iload from the sum of current Ipv and discharge current Idc of power storage device 3 is current Icell. The values of the currents Isel and Ibuy can be freely set by the user or administrator of the DC system.
(双方向DC/AC変換器の構成)
次に、図面を参照して、この発明の実施の形態に従う電力変換装置の一形態である双方向DC/AC変換器40の構成について説明する。 (Configuration of bidirectional DC / AC converter)
Next, with reference to the drawings, the configuration of bidirectional DC /AC converter 40 which is one form of the power conversion device according to the embodiment of the present invention will be described.
次に、図面を参照して、この発明の実施の形態に従う電力変換装置の一形態である双方向DC/AC変換器40の構成について説明する。 (Configuration of bidirectional DC / AC converter)
Next, with reference to the drawings, the configuration of bidirectional DC /
図2は、図1における双方向DC/AC変換器40の詳細な構成を示す回路図である。
図2を参照して、双方向DC/AC変換器40は、双方向インバータ400と、連系リアクトル410,412と、電流センサ430と、電圧センサ440と、制御部420とを含む。 FIG. 2 is a circuit diagram showing a detailed configuration of the bidirectional DC /AC converter 40 in FIG.
Referring to FIG. 2, bidirectional DC /AC converter 40 includes a bidirectional inverter 400, interconnection reactors 410 and 412, a current sensor 430, a voltage sensor 440, and a control unit 420.
図2を参照して、双方向DC/AC変換器40は、双方向インバータ400と、連系リアクトル410,412と、電流センサ430と、電圧センサ440と、制御部420とを含む。 FIG. 2 is a circuit diagram showing a detailed configuration of the bidirectional DC /
Referring to FIG. 2, bidirectional DC /
双方向インバータ400は、売電時には、制御部420からのスイッチング制御信号S1~S4に応じて、直流バス1から受けた直流電力を交流電力に変換して系統電力42に出力する。また、双方向インバータ400は、買電時には、制御部420からのスイッチング制御信号S1~S4に応じて、系統電力42から受けた交流電力を直流電力に変換して直流バス1に出力する。
The bidirectional inverter 400 converts the DC power received from the DC bus 1 into AC power and outputs it to the system power 42 in response to the switching control signals S1 to S4 from the control unit 420 at the time of power sale. Bidirectional inverter 400 converts AC power received from system power 42 into DC power and outputs it to DC bus 1 in accordance with switching control signals S 1 to S 4 from control unit 420 during power purchase.
具体的には、双方向インバータ400は、スイッチング素子であるトランジスタQ1~Q4と、ダイオードD1~D4とを含む。トランジスタQ1,Q2は、直流バス1を構成する正母線PLおよび負母線NLの間に直列に接続される。トランジスタQ1とトランジスタQ2との中間点はR相線RLに接続される。連系リアクトル410は、R相線RLに介挿接続される。
Specifically, the bidirectional inverter 400 includes transistors Q1 to Q4, which are switching elements, and diodes D1 to D4. Transistors Q1 and Q2 are connected in series between positive bus PL and negative bus NL constituting DC bus 1. An intermediate point between transistors Q1 and Q2 is connected to R-phase line RL. Interconnection reactor 410 is connected to R-phase line RL.
トランジスタQ3,Q4は、正母線PLおよび負母線NLの間に直列に接続される。トランジスタQ3とトランジスタQ4との中間点はT相線TLに接続される。連系リアクトル412は、T相線TLに介挿接続される。各トランジスタQ1~Q4のコレクタ-エミッタ間には、エミッタ側からコレクタ側へ電流を流すダイオードD1~D4がそれぞれ接続されている。トランジスタQ1~Q4およびダイオードD1~D4は、フルブリッジ回路を構成する。
Transistors Q3 and Q4 are connected in series between positive bus PL and negative bus NL. An intermediate point between transistors Q3 and Q4 is connected to T-phase line TL. Interconnected reactor 412 is connected to T-phase line TL. Between the collector and emitter of each of the transistors Q1 to Q4, diodes D1 to D4 that flow current from the emitter side to the collector side are respectively connected. Transistors Q1-Q4 and diodes D1-D4 constitute a full bridge circuit.
なお、トランジスタQ1~Q4として、例えば、IGBT(Insulated Gate Bipolar Transistor)を用いることができる。または、パワーMOSFET(Metal Oxide Semiconductor Field-Effect Transistor)等の電力スイッチング素子を用いてもよい。
For example, IGBTs (Insulated Gate Bipolar Transistors) can be used as the transistors Q1 to Q4. Alternatively, a power switching element such as a power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) may be used.
電流センサ430は、負母線SLに介挿され、直流バス1および双方向インバータ400の間で授受される電力の電流値(自経路電流)Iinvを検出し、その検出結果を制御部420へ出力する。電流センサ430は「自経路電流検出部」に対応する。
Current sensor 430 is inserted in negative bus SL, detects a current value (own path current) Iinv of power exchanged between DC bus 1 and bidirectional inverter 400, and outputs the detection result to control unit 420. To do. The current sensor 430 corresponds to a “self-path current detection unit”.
電圧センサ440は、正母線PLと負母線SLとの間に接続され、双方向インバータ400および系統電力42の間で授受される電力の電圧値Vdcを検出し、その検出結果を制御部420へ出力する。なお、上記のように、蓄電装置3は直流バス1に「直結」されていることから、直流バス1の電圧Vdcは電池電圧Vbに等しい。現実には、電圧値Vd1および電池電圧Vbとの間には、配線インピーダンスによって若干の電圧差が生じるが、本実施の形態では無視できるほど小さいものとする。
Voltage sensor 440 is connected between positive bus PL and negative bus SL, detects voltage value Vdc of power transferred between bidirectional inverter 400 and system power 42, and outputs the detection result to control unit 420. Output. As described above, since the power storage device 3 is “directly connected” to the DC bus 1, the voltage Vdc of the DC bus 1 is equal to the battery voltage Vb. In reality, a slight voltage difference is generated between the voltage value Vd1 and the battery voltage Vb due to the wiring impedance, but it is assumed to be negligibly small in the present embodiment.
制御部420は、電流センサ430から受けた自経路電流Iinvと、電圧センサ44から受けた電圧Vdcと、電流センサ60から受けた電池電流Ibと、電池監視ユニット6からの電池データ(電池電圧Vb、電池温度Tbおよび電池残量SOC)とに基づいて、後述する制御構造に従って、トランジスタQ1~Q4のオン・オフを制御するためのスイッチング制御信号S1~S4を生成し、双方向インバータ400を制御する。
The control unit 420 includes the own path current Iinv received from the current sensor 430, the voltage Vdc received from the voltage sensor 44, the battery current Ib received from the current sensor 60, and battery data (battery voltage Vb from the battery monitoring unit 6). Based on the battery temperature Tb and the remaining battery charge SOC), the switching control signals S1 to S4 for controlling on / off of the transistors Q1 to Q4 are generated according to the control structure described later, and the bidirectional inverter 400 is controlled. To do.
具体的には、制御部420は、双方向インバータ400における制御目標値を設定する。この制御目標値には、自経路電流Iinvの電流目標値Inv*と、電池電流Ibの電流目標値Ib*とが含まれる。以下の説明では、自経路電流Iinvの電流目標値Iinv*を「自経路電流目標値」とも記し、電池電流Ibの電流目標値Ib*を「電池電流目標値」とも表記する。
Specifically, the control unit 420 sets a control target value in the bidirectional inverter 400. This control target value includes a current target value Inv * of the own path current Iinv and a current target value Ib * of the battery current Ib. In the following description, the current target value Iinv * of the own path current Iinv is also referred to as “own path current target value”, and the current target value Ib * of the battery current Ib is also referred to as “battery current target value”.
制御目標値(自経路電流目標値Iinv*および電池電流目標値Ib*)は、たとえば日時や蓄電装置3の電池残量(SOC)に応じて異なる値となるように事前に決定し、図示しないメモリに格納しておくことができる。図3は、双方向DC/AC変換器40が用いる目標値設定表の一例を示す図である。同図では、電池電流は、上記のように、蓄電装置3の充電方向を正方向とし、蓄電装置3の放電方向を負方向として表記されている。また、自経路電流Iinvは、売電方向を正方向とし、買電方向を負方向として表記されている。電池電流目標値Ib*は、充電電流Ichの電流目標値Ich*と、放電電流Idcの電流目標値Idc*とを含む。自経路電流目標値Iinv*は、売電時の自経路電流Isellの電流目標値Isell*と、買電時の自経路電流Ibuyの電流目標値Ibuy*とを含む。
The control target values (the self-path current target value Iinv * and the battery current target value Ib *) are determined in advance so as to be different values depending on, for example, the date and time or the remaining battery level (SOC) of the power storage device 3, and are not illustrated. Can be stored in memory. FIG. 3 is a diagram illustrating an example of a target value setting table used by the bidirectional DC / AC converter 40. In the figure, as described above, the battery current is represented with the charging direction of the power storage device 3 as a positive direction and the discharge direction of the power storage device 3 as a negative direction. The self-path current Iinv is described with the power selling direction as the positive direction and the power purchase direction as the negative direction. Battery current target value Ib * includes current target value Ich * of charging current Ich and current target value Idc * of discharge current Idc. The own path current target value Iinv * includes a current target value Isel * of the own path current Isel at the time of power sale and a current target value Ibuy * of the own path current Ibuy at the time of power purchase.
制御部420は、図3に示す目標値設定表に従って、日時および蓄電装置3の電池残量に応じて、自経路電流目標値Iinv*または電池電流目標値Ib*を設定する。あるいは、制御部420と直流システムの外部との間で通信を行なうことによって、図3の目標値設定表に従って設定された制御目標値を取得するようにしてもよい。
Control unit 420 sets own path current target value Iinv * or battery current target value Ib * according to the date and time and the remaining battery level of power storage device 3 in accordance with the target value setting table shown in FIG. Or you may make it acquire the control target value set according to the target value setting table | surface of FIG. 3 by communicating between the control part 420 and the exterior of a DC system.
図3を参照して、たとえば7時~17時の時間帯であって、蓄電装置3の電池残量(SOC)が20%以上80%未満の場合には、太陽光発電システム2が発電した電力を積極的に売電するように、自経路電流目標値Iinv*を10Aに設定する。すなわち、売電時の自経路電流目標値Isell*を10Aに設定する。この場合、制御部420は、自経路電流Iinvが自経路電流目標値Iinv*となるようにスイッチング制御信号S1~S4を生成して双方向インバータ400を制御する。
Referring to FIG. 3, for example, in the time zone from 7:00 to 17:00, when the remaining battery level (SOC) of power storage device 3 is 20% or more and less than 80%, solar power generation system 2 generates power. The self-path current target value Iinv * is set to 10 A so as to actively sell power. That is, the self-path current target value Isell * at the time of power sale is set to 10A. In this case, the control unit 420 controls the bidirectional inverter 400 by generating the switching control signals S1 to S4 so that the own path current Iinv becomes the own path current target value Iinv *.
一方、7時~17時の時間帯であって、蓄電装置3の電池残量が20%未満の場合には、太陽光発電システム2で発電した電力で蓄電装置3が充電されるように、電池電流目標値Ib*を8Aに設定する。すなわち、蓄電装置3の充電電流Ichの電流目標値Ich*を8Aに設定する。この場合、制御部420は、電池電流Ibが電池電流目標値Ib*となるようにスイッチング制御信号S1~S4を生成して双方向インバータ400を制御する。
On the other hand, in the time zone from 7:00 to 17:00, when the remaining battery level of the power storage device 3 is less than 20%, the power storage device 3 is charged with the power generated by the solar power generation system 2. The battery current target value Ib * is set to 8A. That is, current target value Ich * of charging current Ich of power storage device 3 is set to 8A. In this case, the control unit 420 controls the bidirectional inverter 400 by generating the switching control signals S1 to S4 so that the battery current Ib becomes the battery current target value Ib *.
以下の説明では、それぞれの電流制御を区別するために、自経路電流目標値Iinv*に基づいた電流制御を「自経路電流制御」とも記し、電池電流目標値Ib*に基づいた電流制御を「電池電流制御」とも表記する。
In the following description, in order to distinguish each current control, the current control based on the own path current target value Iinv * is also referred to as “own path current control”, and the current control based on the battery current target value Ib * is “ Also referred to as “battery current control”.
(1)自経路電流制御
図4および図5は、本発明の実施の形態による双方向DC/AC変換器40における自経路電流制御を説明するための図である。 (1) Self-path current control FIGS. 4 and 5 are diagrams for explaining self-path current control in bidirectional DC /AC converter 40 according to the embodiment of the present invention.
図4および図5は、本発明の実施の形態による双方向DC/AC変換器40における自経路電流制御を説明するための図である。 (1) Self-path current control FIGS. 4 and 5 are diagrams for explaining self-path current control in bidirectional DC /
図4を参照して、図3に示す目標値設定表に従って自経路電流目標値Iinv*が-10Aに設定された場合(電流目標値Ibuy*=10Aに設定された場合)を想定する。
Referring to FIG. 4, it is assumed that the own path current target value Iinv * is set to −10 A according to the target value setting table shown in FIG. 3 (the current target value Ibuy * = 10 A).
この場合、双方向DC/AC変換器40は、自経路電流Iinv=-10A(Ibuy=10A)で買電するように電力変換動作を行なう。具体的には、双方向DC/AC変換器40は、自経路電流目標値Iinv*に対する自経路電流Iinvの電流偏差に応じて生成されたスイッチング制御信号S1~S4に応答したスイッチング動作により、系統電力42から受ける交流電力を直流電力に変換して直流バス1へ供給する。
In this case, the bidirectional DC / AC converter 40 performs a power conversion operation so as to purchase power with its own path current Iinv = −10 A (Ibuy = 10 A). Specifically, the bidirectional DC / AC converter 40 performs the switching operation in response to the switching control signals S1 to S4 generated according to the current deviation of the own path current Iinv with respect to the own path current target value Iinv *. The AC power received from the power 42 is converted into DC power and supplied to the DC bus 1.
ここで、太陽光発電システム2の出力電流Ipv=5Aであり、直流負荷5に供給される電流Iload=3Aであるとすると、自経路電流Iinv=-10Aで買電することによって、電流Ipvおよび電流Iinvの和から電流Iloadを差し引いた電流=12Aで蓄電装置3が充電されることとなる(電池電流Ib=12A)。
Here, assuming that the output current Ipv = 5 A of the photovoltaic power generation system 2 and the current Iload = 3 A supplied to the DC load 5, the current Ipv and the current Ipv can be obtained by purchasing with the own path current Iinv = −10 A. The power storage device 3 is charged with a current obtained by subtracting the current Iload from the sum of the currents Iinv = 12 A (battery current Ib = 12 A).
その一方で、蓄電装置3においては、その仕様上、蓄電装置3に流すことのできる電流の範囲が定められている。この電流範囲は、たとえば蓄電装置3の定格容量に基づいて定められる。本実施の形態では、一例として、1C=10Aを電流範囲の上下限値とする。すなわち、電池電流Ibを、-10A~10Aの範囲内に収める必要がある。
On the other hand, in the power storage device 3, the range of current that can be passed through the power storage device 3 is determined due to its specifications. This current range is determined based on the rated capacity of power storage device 3, for example. In this embodiment, as an example, 1C = 10 A is set as the upper and lower limit values of the current range. That is, the battery current Ib needs to fall within the range of −10A to 10A.
しかしながら図4においては、蓄電装置3は電池電流Ib=12Aで充電されることとなり、電流範囲の上限値10Aを上回る電流が蓄電装置3に流れてしまう。これにより、蓄電装置3の性能劣化が進行する虞がある。
However, in FIG. 4, the power storage device 3 is charged with the battery current Ib = 12 A, and a current exceeding the upper limit value 10 A of the current range flows to the power storage device 3. Thereby, there exists a possibility that the performance degradation of the electrical storage apparatus 3 may advance.
そこで、本実施の形態では、自経路電流目標値Iinv*に従った電流制御を実行中に電池電流Ibが所定の電流範囲から外れた場合には、電池電流Ibが当該電流範囲に収まるように、自経路電流目標値Iinv*を調整する。
Therefore, in the present embodiment, when the battery current Ib deviates from a predetermined current range during execution of current control according to the self-path current target value Iinv *, the battery current Ib is within the current range. The own path current target value Iinv * is adjusted.
具体的には、図4で示したように、電池電流Ibが電流範囲の上限値を超える場合には、その超過分を減らすように自経路電流目標値Iinv*を変更する。図5を参照して、双方向DC/AC変換器40における自経路電流目標値Iinv*を-10Aから-8Aに変更する。すなわち、電流目標値Ibuy*を10Aから8Aに変更する。これにより、双方向DC/AC変換器40は、変更後の自経路電流目標値Iinv*に従って、自経路電流Iinv=-8A(Ibuy=8A)で買電するように電力変換動作を行なう。その結果、蓄電装置3は、電流Ipvおよび電流Iinvの和から電流Iloadを差し引いた電流=10Aで蓄電装置3が充電されることとなり(電池電流Ib=10A)、電池電流Ibが電流範囲内に収められる。
Specifically, as shown in FIG. 4, when the battery current Ib exceeds the upper limit value of the current range, the own path current target value Iinv * is changed so as to reduce the excess amount. Referring to FIG. 5, self-path current target value Iinv * in bidirectional DC / AC converter 40 is changed from −10A to −8A. That is, the current target value Ibuy * is changed from 10A to 8A. Thus, bidirectional DC / AC converter 40 performs a power conversion operation so as to purchase power with self-path current Iinv = −8 A (Ibuy = 8 A) in accordance with target path current target value Iinv * after the change. As a result, power storage device 3 is charged with current = 10 A obtained by subtracting current Iload from the sum of current Ipv and current Iinv (battery current Ib = 10 A), and battery current Ib is within the current range. Can be stored.
図4に示したように、直流バス1に太陽光発電システム2および直流負荷5が接続されて構成された直流システムにおいては、双方向DC/AC変換器40において自経路電流目標値Iinv*に従った電流制御を実行しているときに、太陽光発電システム2における発電電力量や直流負荷5における消費電力量が変動する可能性がある。このような事態となると、蓄電装置3で充放電される電力が変動するため、電池電流Ibが蓄電装置3の電流範囲から外れてしまう虞がある。本実施の形態による電力変換装置では、図3の目標値設定表に基づいて設定された自経路電流目標値Iinv*を初期値として、電池電流Ibが電流範囲内に収まるように自経路電流目標値Iinv*を調整する。これにより、電力変換装置における自経路電流制御によって電池電流の超過を解消することができる。その結果、蓄電装置3の性能劣化を回避することができる。
As shown in FIG. 4, in the DC system configured by connecting the photovoltaic power generation system 2 and the DC load 5 to the DC bus 1, the bidirectional DC / AC converter 40 sets the self-path current target value Iinv *. There is a possibility that the amount of generated power in the photovoltaic power generation system 2 or the amount of power consumed in the DC load 5 varies when the current control is executed. In such a situation, the electric power charged / discharged by the power storage device 3 fluctuates, so that the battery current Ib may be out of the current range of the power storage device 3. In the power conversion device according to the present embodiment, the self-path current target is set so that battery current Ib falls within the current range with self-path current target value Iinv * set based on the target value setting table of FIG. 3 as an initial value. Adjust the value Iinv *. Thereby, excess of battery current can be eliminated by self-path current control in the power converter. As a result, performance degradation of the power storage device 3 can be avoided.
以下、図6~図9を参照して、本実施の形態による電力変換装置における自経路電流目標値Iinv*の調整動作を説明する。
Hereinafter, with reference to FIG. 6 to FIG. 9, the adjustment operation of the own path current target value Iinv * in the power conversion device according to the present embodiment will be described.
図6は、図2における制御部420の制御構造を示す図である。
図6を参照して、制御部420は、制御目標値生成部500と、スイッチング素子制御信号生成部510と、メモリ520とを含む。 FIG. 6 is a diagram illustrating a control structure of thecontrol unit 420 in FIG.
Referring to FIG. 6,control unit 420 includes a control target value generation unit 500, a switching element control signal generation unit 510, and a memory 520.
図6を参照して、制御部420は、制御目標値生成部500と、スイッチング素子制御信号生成部510と、メモリ520とを含む。 FIG. 6 is a diagram illustrating a control structure of the
Referring to FIG. 6,
制御目標値生成部500は、双方向DC/AC変換器40の制御目標値として自経路電流目標値Iinv**を生成する。この自経路電流目標値Iinv**は、後述するように、図3の目標値設定表に従って定められた自経路電流目標値Iinv*を初期値とし、自経路電流制御の実行中における電池電流Ibに応じて調整された後の自経路電流目標値に相当する。
The control target value generation unit 500 generates the own path current target value Iinv ** as the control target value of the bidirectional DC / AC converter 40. As will be described later, the self-path current target value Iinv ** is set to the initial value of the self-path current target value Iinv * determined according to the target value setting table of FIG. 3, and the battery current Ib during execution of the self-path current control It corresponds to the self-path current target value after being adjusted according to.
スイッチング素子制御信号生成部510は、制御目標値生成部500から自経路電流目標値Iinv**を受けると、自経路電流Iinvが自経路電流目標値Iinv**となるようにスイッチング制御信号S1~S4を生成して、双方向DC/AC変換器40を制御する。
When the switching element control signal generation unit 510 receives the own path current target value Iinv ** from the control target value generation unit 500, the switching element control signal generation unit 510 switches the switching control signals S1 to S1 so that the own path current Iinv becomes the own path current target value Iinv **. S4 is generated and the bidirectional DC / AC converter 40 is controlled.
具体的には、スイッチング素子制御信号生成部510は、少なくとも比例要素(P:proportional element)および積分要素(I:integral element)を含んで構成され、自経路電流目標値Iinv**に対する自経路電流Iinvの偏差に応じて操作信号を生成する。そして、スイッチング素子制御信号生成部510は、この操作信号に基づいて双方向インバータ400(図2)のトランジスタQ1~Q4のオンデューティーを規定するデューティー指令を生成すると、この生成したデューティー指令と搬送波とを比較することにより、スイッチング制御信号S1~S4を生成する。
Specifically, the switching element control signal generation unit 510 is configured to include at least a proportional element (P) and an integral element (I), and the self-path current with respect to the self-path current target value Iinv **. An operation signal is generated according to the deviation of Iinv. Then, switching element control signal generation unit 510 generates a duty command that defines the on-duty of transistors Q1 to Q4 of bidirectional inverter 400 (FIG. 2) based on this operation signal. Are generated, the switching control signals S1 to S4 are generated.
メモリ520は、情報の読出しおよび書込みが可能であり、たとえばRAM(Random Access Memory)で構成される。メモリ520は、目標値設定表(図3)、蓄電装置3における所定の電流範囲、および蓄電装置3の仕様に応じて逐次更新される電池データを記憶するための記憶領域を有する。この記憶領域には、電流センサ60から送信される電池電流Ibの検出情報(電池電流検出情報)および電流センサ430から送信される自経路電流Iinvの検出情報(自経路電流検出情報)がさらに記憶される。
The memory 520 can read and write information, and is composed of, for example, a RAM (Random Access Memory). Memory 520 has a storage area for storing target value setting table (FIG. 3), a predetermined current range in power storage device 3, and battery data that is sequentially updated according to the specifications of power storage device 3. In this storage area, detection information of the battery current Ib transmitted from the current sensor 60 (battery current detection information) and detection information of the own path current Iinv transmitted from the current sensor 430 (own path current detection information) are further stored. Is done.
制御目標値生成部500は、電流センサ430から自経路電流Iinvを受け、電流センサ60から電池電流Ibを受け、電池監視ユニット6から蓄電装置3の電池残量(SOC)を受ける。制御目標値生成部500は、これらの入力情報と、メモリ520に格納された情報とに基づいて、自経路電流目標値Iinv**を生成する。
Control target value generation unit 500 receives self-path current Iinv from current sensor 430, battery current Ib from current sensor 60, and battery remaining amount (SOC) of power storage device 3 from battery monitoring unit 6. The control target value generation unit 500 generates the own path current target value Iinv ** based on the input information and the information stored in the memory 520.
なお、図6では、制御目標値生成部500が電池監視ユニット6から蓄電装置3の電池残量を受ける例を示したが、制御目標値生成部500自らが、電池電流Ibの検出情報および/または電池電圧Vbの検出情報に基づいて、蓄電装置3の電池残量を推定する構成としてもよい。たとえば、電圧センサ62から送信される電池電圧Vbの検出値に基づいて、蓄電装置3のOCVとSOCとの関係を参照することにより、SOC推定値を算出する態様としてもよい。
6 shows an example in which the control target value generation unit 500 receives the remaining battery level of the power storage device 3 from the battery monitoring unit 6, but the control target value generation unit 500 itself detects the detection information of the battery current Ib and / or Or it is good also as a structure which estimates the battery remaining charge of the electrical storage apparatus 3 based on the detection information of the battery voltage Vb. For example, the estimated SOC value may be calculated by referring to the relationship between the OCV and the SOC of the power storage device 3 based on the detected value of the battery voltage Vb transmitted from the voltage sensor 62.
図7は、本実施の形態による電力変換装置の自経路電流制御を実現するための制御処理手順を示したフローチャートである。図7に示すフローチャートによる制御処理は、一定の制御周期毎に制御部420によって実行される。また、図7に示した各ステップは、制御部420によるソフトウェア処理および/またはハードウェア処理によって実現されるものとする。
FIG. 7 is a flowchart showing a control processing procedure for realizing the self-path current control of the power conversion device according to the present embodiment. The control process according to the flowchart shown in FIG. 7 is executed by the control unit 420 at regular intervals. In addition, each step illustrated in FIG. 7 is realized by software processing and / or hardware processing by the control unit 420.
図7を参照して、制御部420は、ステップS100により、自経路電流Iinvの電流目標値Iinv**を設定する。具体的には、制御部420は、メモリ520に格納された目標値設定表(図3)を参照することにより、日時および蓄電装置3の電池残量に基づいて自経路電流目標値Iinv*を設定する。すなわち、ステップS100の処理は、制御目標値生成部500の機能に対応する。制御部420は、この目標値設定表(図3)に従って定められた自経路電流目標値Iinv*を、自経路電流目標値Iinv**の初期値とする。すなわち、初期値Iinv*は、日時および蓄電装置3の電池残量に応じて変化する可変値となる。
Referring to FIG. 7, control unit 420 sets current target value Iinv ** of self-path current Iinv in step S100. Specifically, control unit 420 refers to target value setting table (FIG. 3) stored in memory 520 to determine self-path current target value Iinv * based on the date and time and the remaining battery level of power storage device 3. Set. That is, the process of step S100 corresponds to the function of the control target value generation unit 500. Control unit 420 sets self-path current target value Iinv * determined according to the target value setting table (FIG. 3) as an initial value of self-path current target value Iinv **. That is, initial value Iinv * is a variable value that changes according to the date and time and the remaining battery level of power storage device 3.
次に、制御部420は、ステップS200により、自経路電流Iinvが自経路電流目標値Iinv**となるようにスイッチング制御信号S1~S4を生成して、双方向インバータ400を制御する(電流制御)。
Next, in step S200, control unit 420 generates switching control signals S1 to S4 so that self-path current Iinv becomes self-path current target value Iinv **, and controls bidirectional inverter 400 (current control). ).
さらに、制御部420は、ステップS300により、双方向インバータ400における電力変換動作の実行中に、電流センサ60により検出される電池電流Ib(電池電流検出情報)を取得すると、この取得された電池電流Ibに基づいて、自経路電流目標値Iinv**を調整する。具体的には、制御部420は、メモリ520に格納された蓄電装置3の電流範囲と、電池電流Ibとを比較する。そして、制御部420は、この比較結果に基づいて自経路電流目標値Iinv**を調整する。このステップS300の機能は、図6に示した制御目標値生成部500の機能に相当する。
Further, when the control unit 420 acquires the battery current Ib (battery current detection information) detected by the current sensor 60 during the power conversion operation in the bidirectional inverter 400 in step S300, the acquired battery current is acquired. Based on Ib, the self-path current target value Iinv ** is adjusted. Specifically, control unit 420 compares the current range of power storage device 3 stored in memory 520 with battery current Ib. Then, the control unit 420 adjusts the own path current target value Iinv ** based on the comparison result. The function of step S300 corresponds to the function of the control target value generation unit 500 shown in FIG.
図8は、図7のステップS200およびS300の処理をさらに詳細に説明するフローチャートである。
FIG. 8 is a flowchart for explaining the processing in steps S200 and S300 in FIG. 7 in more detail.
図8を参照して、制御部420は、ステップS01では、電流センサ430により検出される自経路電流Iinvと、自経路電流目標値Iinv**とを比較する。自経路電流Iinvが自経路電流目標値Iinv**よりも小さい場合(ステップS01のYES判定時)には、制御部420は、ステップS02により、自経路電流Iinvと自経路電流目標値Iinv**との電流偏差に基づいたスイッチング制御信号S1~S4を生成する。このような制御を行なうことにより、自経路電流Iinvは正方向(売電方向)に変化する(すなわち、自経路電流Iinvが増加)。
Referring to FIG. 8, in step S01, control unit 420 compares self-path current Iinv detected by current sensor 430 with self-path current target value Iinv **. When the self-path current Iinv is smaller than the self-path current target value Iinv ** (when YES is determined in step S01), the control unit 420 performs the self-path current Iinv and the self-path current target value Iinv ** in step S02. The switching control signals S1 to S4 are generated based on the current deviation. By performing such control, the own path current Iinv changes in the positive direction (the power selling direction) (that is, the own path current Iinv increases).
一方、自経路電流Iinvが自経路電流目標値Iinv**以上となる場合(ステップS01のNO判定時)には、制御部420は、ステップS03により、自経路電流Iinvと自経路電流目標値Iinv**との電流偏差に基づいたスイッチング制御信号S1~S4を生成する。このような制御を行なうことにより、自経路電流Iinvが負方向(買電方向)に変化する(すなわち、自経路電流Iinvが減少)。ステップS01~S03の処理は、図7に示したステップS200の処理に相当する。
On the other hand, when the self-path current Iinv is equal to or greater than the self-path current target value Iinv ** (when NO is determined in step S01), the control unit 420 performs the self-path current Iinv and the self-path current target value Iinv in step S03. Switching control signals S1 to S4 are generated based on the current deviation from **. By performing such control, the own path current Iinv changes in the negative direction (the power purchase direction) (that is, the own path current Iinv decreases). The processing in steps S01 to S03 corresponds to the processing in step S200 shown in FIG.
制御部420は、上記S01~S03に示した電流制御の実行中に、電流センサ60から電池電流Ib(電池電流検出情報)を取得する。そして、制御部420は、電池電流Ibが蓄電装置3の電流範囲内に収まっているか否かを判定する。具体的には、ステップS04では、制御部420は、電池電流Ibが電流範囲の下限値(たとえば-10A)以上であるか否かを判定する。電池電流Ibが当該下限値よりも小さい場合には(ステップS04のNO判定時)、制御部420は、ステップS05により、自経路電流目標値Iinv**を所定量ΔI1だけ減少させる。
The control unit 420 acquires the battery current Ib (battery current detection information) from the current sensor 60 during the execution of the current control shown in S01 to S03. Then, control unit 420 determines whether or not battery current Ib is within the current range of power storage device 3. Specifically, in step S04, control unit 420 determines whether or not battery current Ib is greater than or equal to the lower limit value (eg, −10 A) of the current range. When the battery current Ib is smaller than the lower limit (when NO is determined in step S04), the control unit 420 decreases the own path current target value Iinv ** by a predetermined amount ΔI1 in step S05.
すなわち、放電電流Idcが蓄電装置3の電流範囲から外れる場合(ステップS04のNO判定時)には、制御部420は、自経路電流目標値Iinv**を減少させるように自経路電流目標値Iinv**を調整する。双方向DC/AC変換器40においては、調整後の自経路電流目標値Iinv**に従って電力変換動作が実行されることにより、売電時における自経路電流Isellが減少する一方で、買電時における自経路電流Ibuyが増加する。このように売電時および買電時の各々において蓄電装置3から直流バス1に供給される電力が減少するように、自経路電流目標値Iinv**を調整することにより、蓄電装置3の放電電流Idcが電流範囲内に収まる。
That is, when discharge current Idc is out of the current range of power storage device 3 (when NO is determined in step S04), control unit 420 causes self-path current target value Iinv to decrease self-path current target value Iinv **. Adjust **. In the bidirectional DC / AC converter 40, the power conversion operation is executed in accordance with the adjusted self-path current target value Iinv **, thereby reducing the self-path current Isel at the time of power sale while purchasing power. The self-path current Ibuy at increases. As described above, the self-path current target value Iinv ** is adjusted so that the electric power supplied from the power storage device 3 to the DC bus 1 is decreased at the time of both selling and buying power, thereby discharging the power storage device 3. The current Idc is within the current range.
これに対して、電池電流Ibが電流範囲の下限値以上である場合(ステップS04のYES判定時)には、制御部420は、さらにステップS06により、電池電流Ibが電流範囲の上限値(10A)以下であるか否かを判定する。電池電流Ibが当該上限値よりも大きい場合(ステップS06のNO判定時)には、制御部420は、ステップS07により、自経路電流目標値Iinv**を所定量ΔI1だけ増加させる。
On the other hand, when battery current Ib is equal to or greater than the lower limit value of the current range (when YES is determined in step S04), control unit 420 further determines that battery current Ib is the upper limit value (10A) of the current range in step S06. ) Determine whether or not: When battery current Ib is larger than the upper limit value (when NO is determined in step S06), control unit 420 increases own path current target value Iinv ** by a predetermined amount ΔI1 in step S07.
すなわち、充電電流Ichが蓄電装置3の電流範囲から外れる場合(ステップS06のNO判定時)には、制御部420は、自経路電流目標値Iinv**を増加させるように自経路電流目標値Iinv**を調整する。双方向DC/AC変換器40においては、調整後の自経路電流目標値Iinv**に従って電力変換動作が実行されることにより、売電時における自経路電流Isellが増加する一方で、買電時における自経路電流Ibuyが減少する。このように売電時および買電時の各々において直流バス1から蓄電装置3に供給される電力が減少するように、自経路電流目標値Iinv**を調整することにより、蓄電装置3の充電電流Ichが電流範囲内に収まる。
That is, when charging current Ich is out of the current range of power storage device 3 (NO determination in step S06), control unit 420 causes self-path current target value Iinv to increase self-path current target value Iinv **. Adjust **. In the bidirectional DC / AC converter 40, the power conversion operation is executed in accordance with the adjusted self-path current target value Iinv **, thereby increasing the self-path current Isel at the time of power sale while purchasing power. The self-path current Ibuy at is reduced. As described above, the self-path current target value Iinv ** is adjusted so that the power supplied from the DC bus 1 to the power storage device 3 is reduced at the time of selling and buying power, thereby charging the power storage device 3. The current Ich falls within the current range.
このように、電池電流Ibが蓄電装置3の電流範囲から外れる場合には、電池電流Ibが当該電流範囲内に収まるように、自経路電流目標値Iinv**を所定量ΔI1だけ増加または減少させる。この所定量ΔI1は、双方向DC/AC変換器40における電流制御の制御速度などを考慮して定められる。
Thus, when the battery current Ib is out of the current range of the power storage device 3, the own path current target value Iinv ** is increased or decreased by a predetermined amount ΔI1 so that the battery current Ib is within the current range. . The predetermined amount ΔI1 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40.
一方、ステップS06において電池電流Ibが電流範囲の上限値以下である場合(ステップS06のYES判定時)、すなわち、電池電流Ibが蓄電装置3の電流範囲内に収まっている場合には、制御部420は、ステップS08~S11により、自経路電流目標値Iinv**を初期値Iinv*に戻すための復帰処理を実行する。
On the other hand, when the battery current Ib is equal to or lower than the upper limit value of the current range in step S06 (when YES is determined in step S06), that is, when the battery current Ib is within the current range of the power storage device 3, the control unit In step S08 to S11, 420 executes a return process for returning the own path current target value Iinv ** to the initial value Iinv *.
具体的には、制御部420は、ステップS08により、自経路電流目標値Iinv**が初期値Iinv*より大きいか否かを判定する。自経路電流目標値Iinv**が初期値Iinv*より大きい場合(ステップS08のYES判定時)には、制御部420は、ステップS09により、自経路電流目標値Iinv**を所定量ΔI2だけ減少させる。
Specifically, the control unit 420 determines whether or not the own path current target value Iinv ** is larger than the initial value Iinv * in step S08. When own path current target value Iinv ** is larger than initial value Iinv * (when YES is determined in step S08), control unit 420 decreases own path current target value Iinv ** by a predetermined amount ΔI2 in step S09. Let
一方、自経路電流目標値Iinv**が初期値Iinv*以下となる場合(ステップS08のNO判定時)には、制御部420はさらにステップS10により、自経路電流目標値Iinv**が初期値Iinv*より小さいか否かを判定する。自経路電流目標値Iinv**が初期値Iinv*より小さい場合(ステップS10のYES判定時)には、制御部420は、ステップS11により、自経路電流目標値Iinv**を所定量ΔI2だけ増加させる。この所定量ΔI2は、双方向DC/AC変換器40における電流制御の制御速度などを考慮して定められる。一方、自経路電流目標値Iinv**が初期値Iinv*と等しい場合(ステップS10のNO判定時)には、上述した自経路電流目標値Iinv**の復帰処理を行なわない。
On the other hand, when the own path current target value Iinv ** is equal to or less than the initial value Iinv * (when NO is determined in step S08), the control unit 420 further performs step S10 to set the own path current target value Iinv ** to the initial value. It is determined whether it is smaller than Iinv *. When own path current target value Iinv ** is smaller than initial value Iinv * (when YES is determined in step S10), control unit 420 increases own path current target value Iinv ** by a predetermined amount ΔI2 in step S11. Let The predetermined amount ΔI2 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40. On the other hand, when the own path current target value Iinv ** is equal to the initial value Iinv * (when NO is determined in step S10), the above-described return processing of the own path current target value Iinv ** is not performed.
上記のステップS08~S11に示した処理は、電池電流Ibを電流範囲内に制御しつつ、自経路電流目標値Iinv**を初期値Iinv*に戻すための処理である。また、ステップS04~S11の処理は、図7に示したステップS300による処理に対応する。
The processing shown in the above steps S08 to S11 is processing for returning the own path current target value Iinv ** to the initial value Iinv * while controlling the battery current Ib within the current range. Further, the processes in steps S04 to S11 correspond to the process in step S300 shown in FIG.
以上説明したように、制御部420は、自経路電流制御の実行中は、電池電流Ibが蓄電装置3の電流範囲内に収まるように自経路電流目標値Iinv**を調整する。これにより、太陽光発電システム2の発電電力量および/または直流負荷5の消費電力量の変動を受けて蓄電装置3で充放電される電力が変動した場合においても、蓄電装置3における電流制限を遵守しつつ、直流バス1に対して電力を授受することができる。
As described above, control unit 420 adjusts self-path current target value Iinv ** so that battery current Ib is within the current range of power storage device 3 during execution of self-path current control. As a result, even when the electric power charged / discharged in the power storage device 3 changes due to fluctuations in the power generation amount of the solar power generation system 2 and / or the power consumption amount of the DC load 5, the current limitation in the power storage device 3 is limited. Electric power can be transferred to the DC bus 1 while complying.
(変更例)
図9は、図7のステップS200およびS300の処理の変更例を説明するフローチャートである。 (Example of change)
FIG. 9 is a flowchart for explaining a modified example of the processing in steps S200 and S300 in FIG.
図9は、図7のステップS200およびS300の処理の変更例を説明するフローチャートである。 (Example of change)
FIG. 9 is a flowchart for explaining a modified example of the processing in steps S200 and S300 in FIG.
図9を参照して、制御部420は、ステップS21により、電流センサ60から電池電流Ib(電池電流検出情報)を取得する。そして、制御部420は、ステップS22により、取得した電池電流Ibとメモリ520に格納されている電池電流Ib♯とを比較する。この電池電流Ib♯は、後述するステップS24において自経路電流目標値Inv**の調整後に取得される電池電流Ibに相当する。
Referring to FIG. 9, control unit 420 acquires battery current Ib (battery current detection information) from current sensor 60 in step S21. In step S22, control unit 420 compares the obtained battery current Ib with the battery current Ib # stored in memory 520. This battery current Ib # corresponds to the battery current Ib acquired after adjustment of the own path current target value Inv ** in step S24 described later.
電池電流Ibが電池電流Ib♯に等しい場合(ステップS22のYES判定時)には、制御部420は、図8と同様のステップS01~S07により、電流センサ60から取得した電池電流Ibに応じて自経路電流目標値Iinv**を調整する。そして、制御部420は、ステップS24により、調整後の自経路電流目標値Iinv**に従って電流制御を行なったときの電池電流Ibを取得してメモリ520に保存する。
When battery current Ib is equal to battery current Ib # (when YES is determined in step S22), control unit 420 performs steps S01 to S07 similar to FIG. 8 according to battery current Ib acquired from current sensor 60. The own path current target value Iinv ** is adjusted. Then, in step S24, control unit 420 obtains battery current Ib when current control is performed in accordance with adjusted self-path current target value Iinv ** and stores it in memory 520.
これに対して、電池電流Ibが電池電流Ib♯と異なる場合(ステップS22のNO判定時)には、制御部420は、ステップS23により、自経路電流目標値Iinv**を初期値Iinv*に戻す。そして、制御部420は、図8と同様のステップS01~S07により、電流センサ60から取得した電池電流Ibに応じて自経路電流目標値Iinv**を調整する。さらに、制御部420は、ステップS24により、調整後の自経路電流目標値Iinv**に従って電流制御を行なったときの電池電流Ibを取得してメモリ520に保存する。
On the other hand, when battery current Ib is different from battery current Ib # (when NO is determined in step S22), control unit 420 changes own path current target value Iinv ** to initial value Iinv * in step S23. return. Then, control unit 420 adjusts own path current target value Iinv ** according to battery current Ib acquired from current sensor 60 through steps S01 to S07 similar to those in FIG. Further, in step S24, control unit 420 acquires battery current Ib when current control is performed in accordance with adjusted self-path current target value Iinv ** and stores it in memory 520.
本変更例では、太陽光発電システム2における発電電力量および/または直流負荷5における消費電力量の変動に起因して蓄電装置3に充放電される電流Ibが変化したときには、調整後の自経路電流目標値Iinv**を初期値Iinv*に戻して自経路電流目標値Iinv**の調整をやり直す。すなわち、自経路電流制御とは異なる外的要因によって電池電流Ibが変化したことをトリガとして、自経路電流目標値Iinv**を初期値Iinv*に戻す。
In this modified example, when the current Ib charged / discharged to / from the power storage device 3 changes due to fluctuations in the power generation amount in the solar power generation system 2 and / or the power consumption amount in the DC load 5, the adjusted self-path The current target value Iinv ** is returned to the initial value Iinv * and the self-path current target value Iinv ** is adjusted again. That is, the self-path current target value Iinv ** is returned to the initial value Iinv *, triggered by a change in the battery current Ib due to an external factor different from the self-path current control.
なお、本実施の形態による蓄電装置3の電流範囲は、上述の例に限定されるものではない。すなわち、蓄電装置3の定格電流(許容充放電電流)を電流範囲(-10A~10A)とする構成に代えて、より電池寿命を長くする観点から、例えば定格電流の80%を電
流範囲の上下限値に設定してもよい。なお、上下限値を定格電流の何%に設定するかについては、電池寿命を考慮した設計思想によって、任意に選択することができる。 The current range of power storage device 3 according to the present embodiment is not limited to the above example. That is, instead of the configuration in which the rated current (allowable charging / discharging current) of the power storage device 3 is set to the current range (−10A to 10A), 80% of the rated current is increased above the current range, for example, from the viewpoint of extending the battery life. You may set to a lower limit. Note that what percentage of the rated current is set to the upper and lower limit values can be arbitrarily selected according to the design concept considering the battery life.
流範囲の上下限値に設定してもよい。なお、上下限値を定格電流の何%に設定するかについては、電池寿命を考慮した設計思想によって、任意に選択することができる。 The current range of power storage device 3 according to the present embodiment is not limited to the above example. That is, instead of the configuration in which the rated current (allowable charging / discharging current) of the power storage device 3 is set to the current range (−10A to 10A), 80% of the rated current is increased above the current range, for example, from the viewpoint of extending the battery life. You may set to a lower limit. Note that what percentage of the rated current is set to the upper and lower limit values can be arbitrarily selected according to the design concept considering the battery life.
また、蓄電装置によっては、許容充電電流と許容放電電流とが異なるものも存在するため、使用する蓄電装置の仕様に応じて、上限値(たとえば3A)と下限値(たとえば-6A)とを異ならせても同様の効果を得ることができる。
Some power storage devices have different allowable charge currents and allowable discharge currents. Therefore, the upper limit value (for example, 3A) and the lower limit value (for example, −6A) are different depending on the specifications of the power storage device to be used. Even if it makes it, the same effect can be acquired.
(2)電池電流制御
次に、本実施の形態による電力変換装置における電池電流制御について説明する。図10を用いて、制御部420による電池電流目標値Ib**の調整動作を詳細に説明する。 (2) Battery Current Control Next, battery current control in the power conversion device according to the present embodiment will be described. The adjustment operation of the battery current target value Ib ** by thecontrol unit 420 will be described in detail with reference to FIG.
次に、本実施の形態による電力変換装置における電池電流制御について説明する。図10を用いて、制御部420による電池電流目標値Ib**の調整動作を詳細に説明する。 (2) Battery Current Control Next, battery current control in the power conversion device according to the present embodiment will be described. The adjustment operation of the battery current target value Ib ** by the
図10を参照して、電池電流制御においては、制御目標値生成部500は、双方向DC/AC変換器40の制御目標値として電池電流目標値Ib**を生成する。この電池電流目標値Ib**は、後述するように、図3の目標値設定表に従って定められた電池電流目標値Ib*を初期値とし、電池電流制御の実行中における自経路電流Iinvに応じて調整された後の電池電流目標値に相当する。
Referring to FIG. 10, in battery current control, control target value generation unit 500 generates battery current target value Ib ** as a control target value of bidirectional DC / AC converter 40. As will be described later, the battery current target value Ib ** corresponds to the self-path current Iinv during execution of the battery current control, with the battery current target value Ib * determined according to the target value setting table of FIG. 3 as an initial value. This corresponds to the target battery current value after adjustment.
スイッチング素子制御信号生成部510は、制御目標値生成部500から電池電流目標値Ib**を受けると、電池電流Ibが電池電流目標値Ib**となるようにスイッチング制御信号S1~S4を生成して、双方向DC/AC変換器40を制御する。
When switching element control signal generator 510 receives battery current target value Ib ** from control target value generator 500, switching element control signal generator 510 generates switching control signals S1 to S4 such that battery current Ib becomes battery current target value Ib **. Then, the bidirectional DC / AC converter 40 is controlled.
具体的には、スイッチング素子制御信号生成部510は、上述した自経路電流制御と同様に、電池電流目標値Ib**に対する電池電流Ibの偏差に応じて操作信号を生成する。そして、スイッチング素子制御信号生成部510は、この操作信号に基づいて双方向インバータ400(図2)のトランジスタQ1~Q4のオンデューティーを規定するデューティー指令を生成すると、この生成したデューティー指令と搬送波とを比較することにより、スイッチング制御信号S1~S4を生成する。
Specifically, the switching element control signal generation unit 510 generates an operation signal according to the deviation of the battery current Ib from the battery current target value Ib **, similarly to the self-path current control described above. Then, switching element control signal generation unit 510 generates a duty command that defines the on-duty of transistors Q1 to Q4 of bidirectional inverter 400 (FIG. 2) based on this operation signal. Are generated, the switching control signals S1 to S4 are generated.
メモリ520の記憶領域には、蓄電装置3における所定の電流範囲に代えて、双方向DC/AC変換器40における所定の電流範囲が記憶されている。この所定の電流範囲は、その仕様上、双方向DC/AC変換器40に流すことのできる電流の範囲に相当する。この電流範囲は、たとえば双方向DC/AC変換器40の定格出力に基づいて定められる。本実施の形態では、一例として、15Aを電流範囲の上下限値とする。すなわち、自経路電流Iinvを、-15A~15Aの範囲内に収める必要がある。
In the storage area of the memory 520, a predetermined current range in the bidirectional DC / AC converter 40 is stored instead of the predetermined current range in the power storage device 3. This predetermined current range corresponds to the range of current that can be passed through the bidirectional DC / AC converter 40 due to its specifications. This current range is determined based on the rated output of the bidirectional DC / AC converter 40, for example. In the present embodiment, as an example, 15 A is set as the upper and lower limit values of the current range. That is, the self-path current Iinv needs to be within the range of −15A to 15A.
制御目標値生成部500は、電流センサ430から自経路電流Iinvを受け、電流センサ60から電池電流Ibを受け、電池監視ユニット6から蓄電装置3の電池残量(SOC)を受ける。制御目標値生成部500は、これらの入力情報と、メモリ520に格納された情報とに基づいて、電池電流目標値Ib**を生成する。
Control target value generation unit 500 receives self-path current Iinv from current sensor 430, battery current Ib from current sensor 60, and battery remaining amount (SOC) of power storage device 3 from battery monitoring unit 6. Control target value generation unit 500 generates battery current target value Ib ** based on these input information and information stored in memory 520.
図11は、本実施の形態による電力変換装置の電池電流制御を実現するための制御処理手順を示したフローチャートである。図11に示すフローチャートによる制御処理は、一定の制御周期毎に制御部420によって実行される。また、図11に示した各ステップは、制御部420によるソフトウェア処理および/またはハードウェア処理によって実現されるものとする。
FIG. 11 is a flowchart showing a control processing procedure for realizing battery current control of the power conversion device according to the present embodiment. The control process according to the flowchart shown in FIG. 11 is executed by the control unit 420 at regular intervals. Each step shown in FIG. 11 is realized by software processing and / or hardware processing by the control unit 420.
図11を参照して、制御部420は、ステップS400により、電池電流Ibの電流目標値(電池電流目標値)Ib**を設定する。具体的には、制御部420は、メモリ520に格納された目標値設定表(図3)を参照することにより、日時および蓄電装置3の電池残量に基づいて電池電流目標値Ib*を設定する。すなわち、ステップS400の処理は、制御目標値生成部500の機能に対応する。制御部420は、この目標値設定表(図3)に従って定められた電池電流目標値Ib*を電池電流目標値Ib**の初期値とする。すなわち、初期値Ib*は、日時および蓄電装置3の電池残量に応じて変化する可変値となる。
Referring to FIG. 11, control unit 420 sets current target value (battery current target value) Ib ** of battery current Ib in step S400. Specifically, control unit 420 refers to a target value setting table (FIG. 3) stored in memory 520 to set battery current target value Ib * based on the date and time and the remaining battery level of power storage device 3. To do. That is, the process of step S400 corresponds to the function of the control target value generation unit 500. Control unit 420 sets battery current target value Ib * determined according to this target value setting table (FIG. 3) as an initial value of battery current target value Ib **. That is, initial value Ib * is a variable value that changes according to the date and time and the remaining battery level of power storage device 3.
次に、制御部420は、ステップS500により、電池電流Ibが電池電流目標値Ib**となるようにスイッチング制御信号S1~S4を生成して、双方向インバータ400を制御する(電流制御)。
Next, in step S500, the control unit 420 generates switching control signals S1 to S4 so that the battery current Ib becomes the battery current target value Ib **, and controls the bidirectional inverter 400 (current control).
さらに、制御部420は、ステップS600により、双方向インバータ400における電力変換動作の実行中に、電流センサ430により検出される自経路電流Iinv(自経路電流検出情報)を取得すると、この取得された自経路電流Iinvに基づいて、電池電流目標値Ib**を調整する。具体的には、制御部420は、メモリ520に格納された双方向DC/AC変換器40の電流範囲と、自経路電流Iinvとを比較する。そして、この比較結果に基づいて電池電流目標値Ib**を調整する。このステップS600の機能は、図10に示した制御目標値生成部500の機能に相当する。
Furthermore, when the control unit 420 acquires the self-path current Iinv (self-path current detection information) detected by the current sensor 430 during execution of the power conversion operation in the bidirectional inverter 400 in step S600, the acquired The battery current target value Ib ** is adjusted based on the own path current Iinv. Specifically, the control unit 420 compares the current range of the bidirectional DC / AC converter 40 stored in the memory 520 with the own path current Iinv. Then, the battery current target value Ib ** is adjusted based on the comparison result. The function of step S600 corresponds to the function of the control target value generation unit 500 shown in FIG.
図12は、図11のステップS500およびS600の処理をさらに詳細に説明するフローチャートである。
FIG. 12 is a flowchart for explaining the processing of steps S500 and S600 of FIG. 11 in more detail.
図12を参照して、制御部420は、ステップS31では、電流センサ60により検出される電池電流Ibと、電池電流目標値Ib**とを比較する。電池電流Ibが電池電流目標値Ib**よりも小さい場合(ステップS31のYES判定時)には、制御部420は、ステップS32により、電池電流Ibと電池電流目標値Ib**との電流偏差に基づいたスイッチング制御信号S1~S4を生成する。このような制御を行なうことにより、電池電流Ibは正方向(充電方向)に変化する(すなわち、電池電流Ibが増加)。
Referring to FIG. 12, in step S31, control unit 420 compares battery current Ib detected by current sensor 60 with battery current target value Ib **. When battery current Ib is smaller than battery current target value Ib ** (when YES is determined in step S31), control unit 420 performs current deviation between battery current Ib and battery current target value Ib ** in step S32. The switching control signals S1 to S4 based on the above are generated. By performing such control, the battery current Ib changes in the positive direction (charging direction) (that is, the battery current Ib increases).
一方、電池電流Ibが電池電流目標値Ib**以上となる場合(ステップS31のNO判定時)には、制御部420は、ステップS33により、電池電流Ibと電池電流目標値Ib**との電流偏差に基づいたスイッチング制御信号S1~S4を生成する。このような制御を行なうことにより、電池電流Ibが負方向(放電方向)に変化する(すなわち、電池電流Ibが減少)。ステップS31~S33の処理は、図11に示したステップS500の処理に相当する。
On the other hand, when the battery current Ib is equal to or greater than the battery current target value Ib ** (when NO is determined in step S31), the control unit 420 determines whether the battery current Ib and the battery current target value Ib ** are set in step S33. Switching control signals S1 to S4 based on the current deviation are generated. By performing such control, the battery current Ib changes in the negative direction (discharge direction) (that is, the battery current Ib decreases). The processing in steps S31 to S33 corresponds to the processing in step S500 shown in FIG.
制御部420は、上記S31~S33に示した電流制御の実行中に、電流センサ430から自経路電流Iinv(自経路電流検出情報)を取得する。そして、制御部420は、自経路電流Iinvが双方向DC/AC変換器40の電流範囲内に収まっているか否かを判定する。具体的には、ステップS34では、制御部420は、自経路電流Iinvが電流範囲の下限値(たとえば-15A)以上であるか否かを判定する。自経路電流Iinvが当該下限値よりも小さい場合には(ステップS34のNO判定時)、制御部420は、ステップS35により、電池電流目標値Ib**を所定量ΔI3だけ減少させる。
The control unit 420 acquires the own path current Iinv (own path current detection information) from the current sensor 430 during the execution of the current control shown in S31 to S33. Then, the control unit 420 determines whether or not the self-path current Iinv is within the current range of the bidirectional DC / AC converter 40. Specifically, in step S34, control unit 420 determines whether or not self-path current Iinv is greater than or equal to the lower limit value (eg, −15 A) of the current range. When the self-path current Iinv is smaller than the lower limit (when NO is determined in step S34), the control unit 420 decreases the battery current target value Ib ** by a predetermined amount ΔI3 in step S35.
すなわち、買電時の自経路電流Ibuyが双方向DC/AC変換器40の電流範囲から外れる場合(ステップS34のNO判定時)には、制御部420は、電池電流目標値Ib**を減少させるように電池電流目標値Ib**を調整する。そして、調整後の電池電流目標値Ib**に従って双方向DC/AC変換器40における電力変換動作が実行されることにより、蓄電装置3においては、充電時における電池電流(充電電流)Ichが減少する一方で、放電時における電池電流(放電電流)Idcが増加する。このように充電時には直流バス1から蓄電装置3に供給される電力が減少する一方で、放電時には蓄電装置3から直流バス1に供給される電力が増加するように、電池電流目標値Ib**を調整することにより、買電時における自経路電流Iinvが電流範囲内に収まる。
In other words, when own path current Ibuy at the time of power purchase is out of the current range of bidirectional DC / AC converter 40 (NO in step S34), control unit 420 decreases battery current target value Ib **. The battery current target value Ib ** is adjusted so that Then, by executing the power conversion operation in bidirectional DC / AC converter 40 according to adjusted battery current target value Ib **, battery current (charging current) Ich at the time of charging is reduced in power storage device 3. On the other hand, the battery current (discharge current) Idc during discharge increases. Thus, the battery current target value Ib ** is such that the power supplied from the DC bus 1 to the power storage device 3 during charging decreases while the power supplied from the power storage device 3 to the DC bus 1 increases during discharging. Is adjusted so that the self-path current Iinv at the time of power purchase falls within the current range.
これに対して、自経路電流Iinvが電流範囲の下限値以上である場合(ステップS34のYES判定時)には、制御部420は、さらにステップS36により、自経路電流Iinvが電流範囲の上限値(15A)以下であるか否かを判定する。自経路電流Iinvが当該上限値よりも大きい場合(ステップS36のNO判定時)には、制御部420は、ステップS37により、電池電流目標値Ib**を所定量ΔI3だけ増加させる。
On the other hand, when the own path current Iinv is equal to or greater than the lower limit value of the current range (when YES is determined in step S34), the control unit 420 further causes the own path current Iinv to exceed the upper limit value of the current range in step S36. (15A) It is determined whether or not. When own path current Iinv is larger than the upper limit value (NO determination in step S36), control unit 420 increases battery current target value Ib ** by a predetermined amount ΔI3 in step S37.
すなわち、売電時の自経路電流Isellが双方向DC/AC変換器40の電流範囲から外れる場合(ステップS36のNO判定時)には、制御部420は、電池電流目標値Ib**を増加させるように電池電流目標値Ib**を調整する。そして、調整後の電池電流目標値Ib**に従って双方向DC/AC変換器40における電力変換動作が実行されることにより、蓄電装置3においては、充電時における電池電流(充電電流)Ichが増加する一方で、放電時における電池電流(放電電流)Idcが減少する。このように充電時には直流バス1から蓄電装置3に供給される電力が増加する一方で、放電時には蓄電装置3から直流バス1に供給される電力が減少するように、電池電流目標値Ib**を調整することにより、売電時における自経路電流Iinvが電流範囲内に収まる。
That is, when self-path current Isel at the time of power sale is out of the current range of bidirectional DC / AC converter 40 (NO determination at step S36), control unit 420 increases battery current target value Ib **. The battery current target value Ib ** is adjusted so that Then, by executing the power conversion operation in bidirectional DC / AC converter 40 according to the adjusted battery current target value Ib **, battery current (charging current) Ich during charging increases in power storage device 3. On the other hand, the battery current (discharge current) Idc during discharge decreases. Thus, the battery current target value Ib ** is such that the power supplied from the DC bus 1 to the power storage device 3 during charging increases while the power supplied from the power storage device 3 to the DC bus 1 decreases during discharging. Is adjusted so that the self-path current Iinv at the time of power sale falls within the current range.
このように、自経路電流Iinvが双方向DC/AC変換器40の電流範囲から外れる場合には、自経路電流Iinvが当該電流範囲内に収まるように、電池電流目標値Ib**を所定量ΔI3だけ増加または減少させる。この所定量ΔI3は、双方向DC/AC変換器40における電流制御の制御速度などを考慮して定められる。
Thus, when the own path current Iinv is out of the current range of the bidirectional DC / AC converter 40, the battery current target value Ib ** is set to a predetermined amount so that the own path current Iinv is within the current range. Increase or decrease by ΔI3. The predetermined amount ΔI3 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40.
一方、ステップS36において自経路電流Iinvが電流範囲の上限値以下である場合(ステップS36のYES判定時)、すなわち、自経路電流Iinvが双方向DC/AC変換器30の電流範囲内に収まっている場合には、制御部420は、電池電流目標値Ib**を初期値Ib*に戻すための復帰処理を実行する。
On the other hand, when the own path current Iinv is equal to or lower than the upper limit value of the current range in step S36 (when YES is determined in step S36), that is, the own path current Iinv falls within the current range of the bidirectional DC / AC converter 30. If so, the control unit 420 executes a return process for returning the battery current target value Ib ** to the initial value Ib *.
具体的には、制御部420は、ステップS38により、電池電流目標値Ib**が初期値Ib*より大きいか否かを判定する。電池電流目標値Ib**が初期値Ib*より大きい場合(ステップS38のYES判定時)には、制御部420は、ステップS39により、電池電流目標値Ib**を所定量ΔI4だけ減少させる。
Specifically, in step S38, control unit 420 determines whether or not battery current target value Ib ** is greater than initial value Ib *. When battery current target value Ib ** is larger than initial value Ib * (when YES is determined in step S38), control unit 420 decreases battery current target value Ib ** by a predetermined amount ΔI4 in step S39.
一方、電池電流目標値Ib**が初期値Ib*以下となる場合(ステップS38のNO判定時)には、制御部420はさらにステップS40により、電池電流目標値Ib**が初期値Ib*より小さいか否かを判定する。電池電流目標値Ib**が初期値Ib*より小さい場合(ステップS40のYES判定時)には、制御部420は、ステップS41により、電池電流目標値Ib**を所定量ΔI4だけ増加させる。所定量ΔI4は、双方向DC/AC変換器40における電流制御の制御速度などを考慮して定められる。一方、電池電流目標値Ib**が初期値Ib*と等しい場合(ステップS40のNO判定時)には、上述した電池電流目標値Ib**の復帰処理を行なわない。
On the other hand, when battery current target value Ib ** is equal to or smaller than initial value Ib * (when NO is determined in step S38), control unit 420 further performs battery current target value Ib ** to initial value Ib * in step S40. It is determined whether it is smaller. When battery current target value Ib ** is smaller than initial value Ib * (when YES is determined in step S40), control unit 420 increases battery current target value Ib ** by a predetermined amount ΔI4 in step S41. The predetermined amount ΔI4 is determined in consideration of the control speed of current control in the bidirectional DC / AC converter 40. On the other hand, when battery current target value Ib ** is equal to initial value Ib * (when NO is determined in step S40), the above-described return processing of battery current target value Ib ** is not performed.
上記のステップS38~S41に示した処理は、自経路電流Iinvが電流範囲内に収まっている状態を保ちつつ、電池電流目標値Ib**を初期値Ib*に戻すための処理である。また、ステップS34~S41の処理は、図10に示したステップS600による処理に対応する。
The processing shown in the above steps S38 to S41 is processing for returning the battery current target value Ib ** to the initial value Ib * while keeping the self-path current Iinv within the current range. Further, the processing in steps S34 to S41 corresponds to the processing in step S600 shown in FIG.
以上説明したように、制御部420は、電池電流制御の実行中は、自経路電流Iinvが双方向DC/AC変換器40の電流範囲内に収まるように電池電流目標値Ib**を調整する。これにより、太陽光発電システム2の発電電力量および/または直流負荷5の消費電力量の変動を受けて直流バス1と双方向DC/AC変換器40との間で授受される電力が変動した場合においても、双方向DC/AC変換器40の電流制限を遵守しつつ、直流バス1に対して電力を授受することができる。
As described above, control unit 420 adjusts battery current target value Ib ** so that self-path current Iinv is within the current range of bidirectional DC / AC converter 40 during execution of battery current control. . As a result, the power exchanged between the DC bus 1 and the bidirectional DC / AC converter 40 fluctuates in response to fluctuations in the amount of power generated by the photovoltaic power generation system 2 and / or the amount of power consumed by the DC load 5. Even in this case, power can be transferred to the DC bus 1 while observing the current limitation of the bidirectional DC / AC converter 40.
(変更例)
図13は、図11のステップS500およびS600の処理の変更例を説明するフローチャートである。 (Example of change)
FIG. 13 is a flowchart for explaining a modified example of the processing of steps S500 and S600 of FIG.
図13は、図11のステップS500およびS600の処理の変更例を説明するフローチャートである。 (Example of change)
FIG. 13 is a flowchart for explaining a modified example of the processing of steps S500 and S600 of FIG.
図13を参照して、制御部420は、ステップS51により、電流センサ430から自経路電流Iinv(自経路電流検出情報)を取得する。そして、制御部420は、ステップS52により、取得した自経路電流Iinvとメモリ520に格納されている自経路電流Iinv♯とを比較する。この自経路電流Iinv♯は、後述するステップS54において電池電流目標値Ib**の調整後に取得される自経路電流Iinvに相当する。
Referring to FIG. 13, control unit 420 acquires own path current Iinv (own path current detection information) from current sensor 430 in step S51. Then, in step S52, control unit 420 compares acquired self path current Iinv with self path current Iinv # stored in memory 520. This own path current Iinv # corresponds to the own path current Iinv acquired after adjustment of the battery current target value Ib ** in step S54 described later.
自経路電流Iinvが自経路電流Iinv♯に等しい場合(ステップS52のYES判定時)には、制御部420は、図12と同様のステップS31~S37により、電流センサ430から取得した自経路電流Iinvに応じて電池電流目標値Ib**を調整する。そして、制御部420は、ステップS54により、調整後の電池電流目標値Ib**に従って電流制御を行なったときの自経路電流Iinvを取得してメモリ520に保存する。
When self-path current Iinv is equal to self-path current Iinv # (when YES is determined in step S52), control unit 420 performs self-path current Iinv acquired from current sensor 430 in steps S31 to S37 similar to FIG. The battery current target value Ib ** is adjusted according to the above. Then, in step S54, control unit 420 obtains self-path current Iinv when current control is performed according to the adjusted battery current target value Ib **, and stores it in memory 520.
本変更例では、太陽光発電システム2における発電電力量および/または直流負荷5における消費電力量の変動に起因して双方向DC/AC変換器40に入出力される電流Iinvが変化したときには、調整後の電池電流目標値Ib**を初期値Ib*に戻して電池電流目標値Ib**の調整をやり直す。すなわち、電池電流制御とは異なる外的要因によって自経路電流Iinvが変化したことをトリガとして、電池電流目標値Ib**を初期値Ib*に戻す。
In this modified example, when the current Iinv input to and output from the bidirectional DC / AC converter 40 changes due to fluctuations in the amount of power generated in the solar power generation system 2 and / or the amount of power consumed in the DC load 5, The battery current target value Ib ** after adjustment is returned to the initial value Ib *, and the battery current target value Ib ** is adjusted again. That is, the battery current target value Ib ** is returned to the initial value Ib * with the trigger that the self-path current Iinv has changed due to an external factor different from the battery current control.
なお、本実施の形態による双方向DC/AC変換器40の電流範囲は、上述の例に限定されるものではない。すなわち、双方向DC/AC変換器40の定格出力を電流範囲とする構成に代えて、例えば定格出力の80%を電流範囲の上下限値に設定してもよい。なお、上下限値を定格出力の何%に設定するかについては、部品寿命を考慮した設計思想によって、任意に選択することができる。また、使用する双方向DC/AC変換器の仕様に応じて、上限値と下限値とを異ならせても同様の効果を得ることができる。
Note that the current range of the bidirectional DC / AC converter 40 according to the present embodiment is not limited to the above example. That is, instead of the configuration in which the rated output of the bidirectional DC / AC converter 40 is set to the current range, for example, 80% of the rated output may be set to the upper and lower limit values of the current range. It should be noted that what percentage of the rated output is set as the upper and lower limit values can be arbitrarily selected according to the design concept in consideration of the component life. Further, the same effect can be obtained even if the upper limit value and the lower limit value are made different according to the specifications of the bidirectional DC / AC converter to be used.
(直流システムの構成例)
上記の説明では、直流システムの一例として、直流バス1に太陽光発電システム2、蓄電装置3、系統電力システム4、および直流負荷5が接続される構成について説明した。しかしながら、本発明の適用はこのような直流システムに限定されるものではない。具体的には、少なくとも直流バス1に蓄電装置3および系統電力システム4が接続されていれば、本発明を適用することが可能である。したがって、例えば図14に示すように、直流バス1に太陽光発電システム2、蓄電装置3および系統電力システム4が接続されて構成された直流システムや、図15に示すように、直流バス1に蓄電装置3および系統電力システム4が接続されて構成された直流システムについても本発明は適用可能である。 (DC system configuration example)
In the above description, as an example of the DC system, the configuration in which the photovoltaicpower generation system 2, the power storage device 3, the system power system 4, and the DC load 5 are connected to the DC bus 1 has been described. However, the application of the present invention is not limited to such a DC system. Specifically, the present invention can be applied as long as the power storage device 3 and the grid power system 4 are connected to at least the DC bus 1. Therefore, for example, as shown in FIG. 14, a DC system configured by connecting the photovoltaic power generation system 2, the power storage device 3, and the system power system 4 to the DC bus 1, or as shown in FIG. 15, The present invention is also applicable to a DC system configured by connecting the power storage device 3 and the system power system 4.
上記の説明では、直流システムの一例として、直流バス1に太陽光発電システム2、蓄電装置3、系統電力システム4、および直流負荷5が接続される構成について説明した。しかしながら、本発明の適用はこのような直流システムに限定されるものではない。具体的には、少なくとも直流バス1に蓄電装置3および系統電力システム4が接続されていれば、本発明を適用することが可能である。したがって、例えば図14に示すように、直流バス1に太陽光発電システム2、蓄電装置3および系統電力システム4が接続されて構成された直流システムや、図15に示すように、直流バス1に蓄電装置3および系統電力システム4が接続されて構成された直流システムについても本発明は適用可能である。 (DC system configuration example)
In the above description, as an example of the DC system, the configuration in which the photovoltaic
また、分散電源装置の一例として、太陽光発電システムを説明したが、風力発電装置および燃料電池などを用いてもよい。
Further, although the solar power generation system has been described as an example of the distributed power supply device, a wind power generation device, a fuel cell, and the like may be used.
さらに、本発明の実施の形態では、電力変換装置の一例として、直流バスおよび系統電力の間で双方向に電力変換を行なう双方向DC/AC変換器について説明したが、直流バスから受ける直流電力を交流電力に変換して系統電力へ供給するためのDC/AC変換器と、系統電力から受ける交流電力を直流バスに変換して直流バスへ供給するためのAC/DC変換器とを備える電力変換装置についても本発明を適用することが可能である。
Furthermore, in the embodiment of the present invention, the bidirectional DC / AC converter that performs bidirectional power conversion between the DC bus and the system power has been described as an example of the power conversion device. DC / AC converter for converting AC power into AC power and supplying it to system power, and AC / DC converter for converting AC power received from system power into a DC bus and supplying it to the DC bus The present invention can also be applied to a conversion device.
今回開示された実施の形態は、すべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は、上記した実施の形態の説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.
1 直流バス、2 太陽光発電システム、3 蓄電装置、4 系統電力システム、5 直流負荷、6 電池監視ユニット、20 太陽電池、22 DC/DC変換器、40 双方向DC/AC変換器、42 系統電力、60,430 電流センサ、62,440 電圧センサ、64 温度センサ、400 双方向インバータ、410,412 連系リアクトル、420 制御部、500 制御目標値生成部、510 スイッチング素子制御信号生成部、520 メモリ。
1 DC bus, 2 solar power generation system, 3 power storage device, 4 grid power system, 5 DC load, 6 battery monitoring unit, 20 solar battery, 22 DC / DC converter, 40 bidirectional DC / AC converter, 42 grid Power, 60,430 current sensor, 62,440 voltage sensor, 64 temperature sensor, 400 bidirectional inverter, 410,412 interconnection reactor, 420 control unit, 500 control target value generation unit, 510 switching element control signal generation unit, 520 memory.
Claims (8)
- 蓄電装置および系統電力の間に配設された直流バスに接続される電力変換装置であって、
前記直流バスおよび前記系統電力の間で電力変換する電力変換部と、
前記電力変換部を流れる自経路電流を検出する自経路電流検出部と、
前記蓄電装置の充放電電流を取得する充放電電流取得部と、
前記電力変換部を制御する制御部とを備え、
前記制御部は、
前記自経路電流が制御目標値になるように前記電力変換部における電力変換を制御するための電力変換制御手段と、
前記電力変換制御手段の実行中に、取得された前記充放電電流が所定の電流範囲に収まるように、前記制御目標値を調整するための調整手段とを含む、電力変換装置。 A power conversion device connected to a DC bus disposed between a power storage device and system power,
A power converter that converts power between the DC bus and the grid power;
A self-path current detection unit for detecting a self-path current flowing through the power conversion unit;
A charge / discharge current acquisition unit for acquiring a charge / discharge current of the power storage device;
A control unit for controlling the power conversion unit,
The controller is
Power conversion control means for controlling power conversion in the power converter so that the self-path current becomes a control target value;
An adjustment device for adjusting the control target value so that the acquired charging / discharging current falls within a predetermined current range during execution of the power conversion control unit. - 前記調整手段は、
予め定められた制御目標値を初期値に設定して前記電力変換制御手段を実行したときの前記充放電電流が前記所定の電流範囲を超えているときに、前記充放電電流に応じて前記制御目標値を変更するための変更手段と、
変更後の前記制御目標値を用いた前記電力変換制御手段の実行中に、前記充放電電流を前記所定の電流範囲に制御しつつ、前記制御目標値を前記初期値に戻すための復帰手段とを含む、請求項1に記載の電力変換装置。 The adjusting means includes
When the power conversion control means is executed with a predetermined control target value set to an initial value, the control is performed according to the charge / discharge current when the charge / discharge current exceeds the predetermined current range. A change means for changing the target value;
A return means for returning the control target value to the initial value while controlling the charge / discharge current to the predetermined current range during execution of the power conversion control means using the control target value after the change; The power converter device of Claim 1 containing this. - 前記調整手段は、
予め定められた制御目標値を初期値に設定して前記電力変換制御手段を実行したときの前記充放電電流が前記所定の電流範囲を超えているときに、前記充放電電流に応じて前記制御目標値を変更するための変更手段と、
変更後の前記制御目標値を用いた前記電力変換制御手段の実行中に、前記充放電電流が前記所定の電流範囲に収まっている状態で、前記充放電電流が変化したときには、前記制御目標値を前記初期値に戻すための復帰手段とを含む、請求項1に記載の電力変換装置。 The adjusting means includes
When the power conversion control means is executed with a predetermined control target value set to an initial value, the control is performed according to the charge / discharge current when the charge / discharge current exceeds the predetermined current range. A change means for changing the target value;
When the charge / discharge current is changed in a state where the charge / discharge current is within the predetermined current range during execution of the power conversion control means using the control target value after the change, the control target value The power conversion device according to claim 1, further comprising a return means for returning the value to the initial value. - 蓄電装置および系統電力の間に配設された直流バスに接続される電力変換装置であって、
前記直流バスおよび前記系統電力の間で電力変換する電力変換部と、
前記電力変換部を流れる自経路電流を検出する自経路電流検出部と、
前記蓄電装置の充放電電流を取得する充放電電流取得部と、
前記電力変換部を制御する制御部とを備え、
前記制御部は、
前記充放電電流が制御目標値になるように前記電力変換部における電力変換を制御するための電力変換制御手段と、
前記電力変換制御手段の実行中に、前記自経路電流の検出値が所定の電流範囲に収まるように、前記制御目標値を調整するための調整手段とを含む、電力変換装置。 A power conversion device connected to a DC bus disposed between a power storage device and system power,
A power converter that converts power between the DC bus and the grid power;
A self-path current detection unit for detecting a self-path current flowing through the power conversion unit;
A charge / discharge current acquisition unit for acquiring a charge / discharge current of the power storage device;
A control unit for controlling the power conversion unit,
The controller is
Power conversion control means for controlling power conversion in the power converter so that the charge / discharge current becomes a control target value;
An adjustment device for adjusting the control target value so that the detected value of the current path current falls within a predetermined current range during execution of the power conversion control means. - 前記調整手段は、
予め定められた制御目標値を初期値に設定して前記電力変換制御手段を実行したときの前記自経路電流の検出値が前記所定の電流範囲を超えているときには、前記自経路電流の検出値に応じて前記制御目標値を変更するための変更手段と、
変更後の前記制御目標値を用いた前記電力変換制御手段の実行中に、前記自経路電電流の検出値を前記所定の電流範囲に制御しつつ、前記制御目標値を前記初期値に戻すための復帰手段とを含む、請求項4に記載の電力変換装置。 The adjusting means includes
When the detected value of the own path current when the predetermined value of the control target is set to the initial value and the power conversion control means is executed exceeds the predetermined current range, the detected value of the own path current Changing means for changing the control target value according to
In order to return the control target value to the initial value while controlling the detected value of the own path electric current to the predetermined current range during execution of the power conversion control means using the control target value after the change. The power conversion device according to claim 4, further comprising: - 前記調整手段は、
予め定められた制御目標値を初期値に設定して前記電力変換制御手段を実行したときの前記自経路電流の検出値が前記所定の電流範囲を超えているときには、前記自経路電流の検出値に応じて前記制御目標値を変更するための変更手段と、
変更後の前記制御目標値を用いた前記電力変換制御手段の実行中に、前記自経路電流の検出値が前記所定の電流範囲に収まっている状態で、前記自経路電流の検出値が変化したときには、前記制御目標値を前記初期値に戻すための復帰手段とを含む、請求項4に記載の電力変換装置。 The adjusting means includes
When the detected value of the own path current when the predetermined value of the control target is set to the initial value and the power conversion control means is executed exceeds the predetermined current range, the detected value of the own path current Changing means for changing the control target value according to
During the execution of the power conversion control means using the control target value after the change, the detected value of the own path current has changed while the detected value of the own path current is within the predetermined current range. 5. The power conversion device according to claim 4, further comprising return means for returning the control target value to the initial value. - 直流バスと、
電源電圧を前記直流バスに出力する蓄電装置と、
前記直流バスおよび系統電力の間に接続される電力変換装置と、
前記電力変換装置を流れる自経路電流を検出する自経路電流検出部と、
前記蓄電装置の充放電電流を検出する充放電電流検出部とを備え、
前記電力変換装置は、
前記直流バスおよび前記系統電力の間で電力変換する電力変換部と、
前記電力変換部を制御する制御部とを含み、
前記制御部は、
前記自経路電流が制御目標値になるように前記電力変換部における電力変換を制御するための電力変換制御手段と、
前記電力変換制御手段の実行中に、前記充放電電流の検出値が所定の電流範囲に収まるように、前記制御目標値を調整するための調整手段とを含む、直流システム。 DC bus,
A power storage device that outputs a power supply voltage to the DC bus;
A power converter connected between the DC bus and system power;
A self-path current detector for detecting a self-path current flowing through the power converter;
A charge / discharge current detector for detecting a charge / discharge current of the power storage device;
The power converter is
A power converter that converts power between the DC bus and the grid power;
A control unit for controlling the power conversion unit,
The controller is
Power conversion control means for controlling power conversion in the power converter so that the self-path current becomes a control target value;
A DC system comprising: adjustment means for adjusting the control target value so that the detected value of the charge / discharge current falls within a predetermined current range during execution of the power conversion control means. - 直流バスと、
電源電圧を前記直流バスに出力する蓄電装置と、
前記直流バスおよび系統電力の間に接続される電力変換装置と、
前記電力変換装置を流れる自経路電流を検出する自経路電流検出部と、
前記蓄電装置の充放電電流を検出する充放電電流検出部とを備え、
前記電力変換装置は、
前記直流バスおよび前記系統電力の間で電力変換する電力変換部と、
前記電力変換部を制御する制御部とを含み、
前記制御部は、
前記充放電電流が制御目標値となるように前記電力変換部における電力変換を制御するための電力変換制御手段と、
前記電力変換制御手段の実行中に、前記自経路電流の検出値が所定の電流範囲に収まるように、前記制御目標値を調整するための調整手段とを含む、直流システム。 DC bus,
A power storage device that outputs a power supply voltage to the DC bus;
A power converter connected between the DC bus and system power;
A self-path current detector for detecting a self-path current flowing through the power converter;
A charge / discharge current detector for detecting a charge / discharge current of the power storage device;
The power converter is
A power converter that converts power between the DC bus and the grid power;
A control unit for controlling the power conversion unit,
The controller is
Power conversion control means for controlling power conversion in the power converter so that the charge / discharge current becomes a control target value;
A DC system comprising: adjustment means for adjusting the control target value so that the detected value of the self-path current falls within a predetermined current range during execution of the power conversion control means.
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