WO2022202206A1 - 電力変換装置 - Google Patents
電力変換装置 Download PDFInfo
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- WO2022202206A1 WO2022202206A1 PCT/JP2022/009252 JP2022009252W WO2022202206A1 WO 2022202206 A1 WO2022202206 A1 WO 2022202206A1 JP 2022009252 W JP2022009252 W JP 2022009252W WO 2022202206 A1 WO2022202206 A1 WO 2022202206A1
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 71
- 239000003990 capacitor Substances 0.000 claims abstract description 236
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- 230000000694 effects Effects 0.000 description 9
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- 230000008859 change Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000007562 laser obscuration time method Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
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- 238000007599 discharging Methods 0.000 description 1
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4283—Arrangements for improving power factor of AC input by adding a controlled rectifier in parallel to a first rectifier feeding a smoothing capacitor
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0083—Converters characterised by their input or output configuration
- H02M1/0085—Partially controlled bridges
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from dc input or output
- H02M1/15—Arrangements for reducing ripples from dc input or output using active elements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4241—Arrangements for improving power factor of AC input using a resonant converter
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4258—Arrangements for improving power factor of AC input using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/2176—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/25—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only arranged for operation in series, e.g. for multiplication of voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0064—Magnetic structures combining different functions, e.g. storage, filtering or transformation
Definitions
- the present disclosure relates to a power conversion device, particularly a circuit that converts AC voltage to DC voltage and isolates input and output.
- a transformer As a circuit that insulates an input from an output and converts an AC voltage to a DC voltage, a transformer, a rectifier circuit and an inverter circuit provided on the primary side of the transformer, and a rectifier provided on the secondary side of the transformer.
- a power conversion device including a circuit is known (for example, Patent Literature 1).
- both rectifier circuits and inverter circuits are each configured by a full bridge circuit.
- an input AC voltage is converted into a DC voltage by a rectifier circuit on the primary side, then converted into a high-frequency AC voltage by an inverter circuit, and applied to a transformer.
- the AC voltage is transmitted to the secondary side of the transformer while being insulated by the transformer, and is converted to DC again by the rectifier circuit on the secondary side.
- the power conversion device described in Patent Document 1 uses a total of three full bridge circuits, two rectifier circuits and one inverter circuit, so the number of active elements is twelve.
- the active element is a general term for a switching element (eg MOSFET) and a rectifying element (eg diode).
- a switching power supply device described in FIG. 23 of Patent Document 2 is known as a circuit that realizes insulation between input and output and conversion from AC voltage to DC voltage with fewer active elements.
- an AC voltage is applied via an inductor to a bridge circuit composed of two switching elements and two rectifying elements, and power factor control is performed by the bridge circuit. Power is then transferred to the secondary side of the transformer through the capacitor and transformer. In the secondary circuit of the transformer, the power transmitted through the capacitor is converted into a DC voltage by the rectifier circuit and output.
- a switching power supply device described in FIG. 23 of Patent Document 2 is composed of seven active elements.
- the two switching elements S1 and S2 that constitute the bridge circuit are simultaneously in a conducting state or in a non-conducting state.
- the switching element Sa is controlled to be in a non-conducting state when the switching elements S1 and S2 are in a conducting state, and to be in a conducting state when the switching elements S1 and S2 are in a non-conducting state. be. Therefore, in the switching power supply device described in FIG. 23 of Patent Document 2, the only control parameter is the duty of the switching elements S1 and S2.
- a power conversion apparatus designed in view of the above problems converts an AC voltage input from an AC power supply into a DC voltage, and includes a transformer having a primary winding and a secondary winding, a first capacitor, and the a primary side circuit having a pair of input terminals to which an AC power supply is connected, a first inductor, an upper arm switching element, a lower arm switching element, an upper arm rectifying element, and a lower arm rectifying element; a rectifying/smoothing circuit having an inductor, a secondary rectifying element, an output capacitor, a first output terminal and a second output terminal, wherein the upper arm switching element and the lower arm switching element are connected in series; , the series connection of the upper arm rectifying element and the lower arm rectifying element constitutes a bridge circuit, a connection point between the upper arm switching element and the lower arm switching element, and a connection point between the upper arm rectifying element and the lower arm switching element.
- a connection point of a rectifying element is connected to the pair of input terminals via the first inductor;
- the primary side circuit includes a buffer circuit having a buffer switching element and a buffer capacitor;
- the first capacitor is connected to the primary winding of the transformer, the rectifying/smoothing circuit is connected to the secondary winding of the transformer, and the power converter includes the upper arm switching element,
- a control unit configured to control switching of the lower arm switching element and the buffer switching element is provided, and the control unit controls the AC power supply when one of the two arm switching elements becomes conductive. are short-circuited through the first inductor, the other of the two arm switching elements is in a non-conducting state, and the buffer switching element is in a conducting state.
- the transformer insulates the input from the output and converts the AC voltage into the DC voltage. This reduces the number of active elements compared to conventional circuits. Also, by using a buffer circuit, a surge voltage caused by leakage inductance of a transformer can be suppressed.
- the switching pattern by including a specific pattern as the switching pattern, it is possible to set two control parameters, the duty of the upper arm switching element or the lower arm switching element and the duty of the buffer switching element.
- two control parameters for example, the output voltage ripple can be reduced while maintaining the performance of power factor control and output voltage control.
- the buffer circuit may be connected in parallel with the bridge circuit. According to such a configuration, the power converter can suppress the generation of surge voltage.
- the buffer circuit may be connected in parallel with the primary winding of the transformer. According to such a configuration, the power converter can suppress surge voltage. Also, the power converter can reduce the voltage applied to the buffer capacitor.
- the power conversion device further includes a second capacitor, the rectifying/smoothing circuit having the first output terminal and the first terminal of the output capacitor connected to each other, and the second output terminal and the second capacitor of the output capacitor.
- a first end of the second inductor is connected to the first end of the output capacitor through the secondary rectifying element, and a second end of the second inductor is connected to the output
- the rectifying/smoothing circuit is connected to the secondary winding of the transformer via the second capacitor, and the primary winding and the secondary winding are connected to the
- the magnetic coupling may be such that when at least one of the upper arm switching element and the lower arm switching element is in a non-conducting state, the secondary side rectifying element conducts.
- the power conversion device further includes a second capacitor, the rectifying/smoothing circuit having the first output terminal and the first terminal of the output capacitor connected to each other, and the second output terminal and the second capacitor of the output capacitor.
- a first end of the secondary side rectifying element is connected to the first end of the output capacitor via the second inductor, and a second end of the secondary side rectifying element is connected to
- the rectifying/smoothing circuit is connected to the second end of the output capacitor, the rectifying/smoothing circuit is connected to the secondary winding of the transformer via the second capacitor, and the primary winding and the secondary winding are , the secondary side rectifying element may be magnetically coupled such that when at least one of the upper arm switching element and the lower arm switching element is in a non-conducting state, the secondary side rectifying element conducts.
- the rectifying/smoothing circuit has a first secondary rectifying element and a second secondary rectifying element as the secondary rectifying elements, and the first output terminal and the output capacitor. and the second output terminal and the second end of the output capacitor are connected, and the first end of the first secondary side rectifying element is connected through the second inductor to the The first end of the first secondary rectifier is connected to the one end of the output capacitor, the second end of the first secondary rectifier is connected to the first end of the secondary winding, and the first end of the second secondary rectifier is connected to the first end of the secondary winding.
- a connection point between the second inductor and the first secondary rectifier, a second end of the secondary rectifier connected to a second end of the secondary winding, and the output capacitor is connected to a midpoint of the secondary winding, and the primary winding and the secondary winding are configured such that one of the upper arm switching element and the lower arm switching element is non-conductive.
- Either the first secondary rectifying element or the second secondary rectifying element may be magnetically coupled so as to have a conductive polarity when in a conductive state.
- the control unit controls switching of the switching elements.
- the switching may be controlled based on the AC voltage and the current flowing through the first inductor so as to improve the power factor of the input power. With such a configuration, it is possible to control the power factor of the power supplied from the AC power supply.
- the control unit controls switching of the switching elements.
- the switching may be controlled so that a predetermined DC voltage is output based on the voltage between the first output terminal and the second output terminal. With such a configuration, the output voltage can be controlled to a desired value.
- the power conversion device 1 is a device that converts an AC voltage supplied from an AC power supply V1 into a DC voltage and supplies the DC voltage to a load connected to the power conversion device 1 .
- the power converter 1 includes, for example, a primary circuit 10, a first capacitor 17, a transformer 18, a second capacitor 19, a rectifying/smoothing circuit 20, and a control section 50.
- the primary side circuit 10 includes, for example, a first inductor 11, an upper arm diode 12, a lower arm diode 13, an upper arm switching element Q1, a lower arm switching element Q2, a first connection line CL1, a second connection A line CL2, a first middle line ML1, a second middle line ML2, a first input terminal t21, a second input terminal t22, and a buffer circuit 40 are provided.
- the upper arm diode 12 is an example of an "upper arm rectifier”
- the lower arm diode 13 is an example of a "lower arm rectifier".
- the AC power supply V1 and the primary circuit 10 are electrically connected. Specifically, the first terminal t11 of the AC power supply V1 and the first input terminal t21 of the primary circuit 10 are connected by the first input line L1. A second input terminal t12 of the AC power supply V1 and a second input terminal t22 of the primary circuit 10 are connected by a second input line L2. As a result, AC voltages are input to the input terminals t21 and t22.
- the upper arm diode 12 and the lower arm diode 13 are connected in series by a second connection line CL2.
- the second connection line CL2 connects the anode of the upper arm diode 12 and the cathode of the lower arm diode 13 .
- the upper arm switching element Q1 has a first end t31 and a second end t32
- the lower arm switching element Q2 has a first end t41 and a second end t42.
- the first connection line CL1 connects the second end t32 of the upper arm switching element Q1 and the first end t41 of the lower arm switching element Q2.
- the upper arm switching element Q1 and the lower arm switching element Q2 are, for example, power switching elements, and are n-type power MOSFETs in this embodiment. Both arm switching elements Q1 and Q2 have body diodes.
- the upper arm switching element Q1 and the lower arm switching element Q2 are not limited to MOSFETs, and may be IGBTs having anti-parallel diodes or the like.
- the first middle line ML1 connects the first connection line CL1 and the first input end t21.
- a first inductor 11 is provided on the first intermediate line ML1.
- the second middle line ML2 connects the second connection line CL2 and the second input end t22. Therefore, the connection point between the two arm switching elements Q1 and Q2 (that is, the point on the first connection line CL1) and the connection point between the two arm diodes 12 and 13 (that is, the point on the second connection line CL2) are They are connected via a pair of input terminals t21 and t22 and the first inductor 11.
- the transformer 18 is an isolation transformer having a primary winding W1 and a secondary winding W2.
- the starting end of the primary winding W1 (the side marked with a black dot in FIG. 1) is connected via the first capacitor 17 to the cathode of the upper arm diode 12 and the first end t31 of the upper arm switching element Q1.
- the first capacitor 17 has a first end t51 and a second end t52.
- the starting end of the primary winding W1 is connected to the second end t52 of the first capacitor 17, and the first end t51 of the first capacitor 17 is connected to the cathode of the upper arm diode 12 and the first end t31 of the upper arm switching element Q1.
- the terminal end of primary winding W1 (the side not marked with a black dot in FIG. 1) is connected to the anode of lower arm diode 13 and second end t42 of lower arm switching element Q2. Therefore, the primary side circuit 10 is connected to the primary winding W1 of the transformer 18 via the first capacitor 17 .
- the rectifying/smoothing circuit 20 includes a second inductor 21, a secondary diode 22, an output capacitor 23, a first output line OL1, a second output line OL2, a first output terminal t91, and a second output terminal t92. and
- the second inductor 21 has a first end t71 and a second end t72, and the output capacitor 23 has a first end t81 and a second end t82.
- the secondary diode 22 is an example of a "secondary rectifier".
- the first end t81 is an example of "one end of the output capacitor, namely the first end”
- the second end t82 is an example of "the other end of the output capacitor, namely the second end”.
- the starting end of the secondary winding W2 (the side marked with a black dot in FIG. 1) is connected via the second capacitor 19 to the first end t71 of the second inductor 21 and the anode of the secondary diode 22.
- the second capacitor 19 has a first end t61 and a second end t62.
- the starting end of the secondary winding W2 is connected to the first end t61 of the second capacitor 19, and the second end t62 of the second capacitor 19 is connected to the first end t71 of the second inductor 21 and the secondary diode 22. connected to the anode.
- the end of the secondary winding W2 (the side not marked with a black dot in FIG. 1) is connected to the second end t72 of the second inductor 21.
- the rectifying/smoothing circuit 20 is connected to the secondary winding W2 of the transformer 18 via the second capacitor 19 .
- the output capacitor 23 is connected to both the first output line OL1 and the second output line OL2. Specifically, the first end t81 of the output capacitor 23 is connected to the first output line OL1. The first output line OL1 is connected to the first output terminal t91. Therefore, it can be said that the first end t81 of the output capacitor 23 is connected to the first output end t91. A second end t82 of the output capacitor 23 is connected to the second output line OL2. The second output line OL2 is connected to the second output terminal t92. Therefore, it can be said that the second end t82 of the output capacitor 23 is connected to the second output end t92.
- the second inductor 21 is connected to both the secondary diode 22 and the second output line OL2. Specifically, the first end t71 of the second inductor 21 is connected to the anode of the secondary diode 22, and the second end t72 of the second inductor 21 is connected to the second output line OL2.
- the first end t71 is an example of "one end of the second inductor, that is, the first end”
- the second end t72 is "the other end of the second inductor, That is, it is an example of "second end”.
- the secondary diode 22 is provided between the second inductor 21 and the output capacitor 23 . As described above, the anode of the secondary diode 22 and the first end t71 of the second inductor 21 are connected. Also, the cathode of the secondary diode 22 and the first end t81 of the output capacitor 23 are connected.
- the buffer circuit 40 includes a buffer switching element Q3, a buffer capacitor Cc, and a third connection line CL3.
- the buffer switching element Q3 and the buffer capacitor Cc are connected in series by a third connection line CL3.
- Buffer switching element Q3 has terminals tq1 and tq2, and buffer capacitor Cc has terminals tc1 and tc2.
- a terminal tq1 of the buffer switching element Q3 and a terminal tc1 of the buffer capacitor Cc are connected by a third connection line CL3.
- Buffer switching element Q3 has a body diode.
- the anode of the body diode of buffer switching element Q3 is connected to terminal tq2, and the cathode of the body diode of buffer switching element Q3 is connected to terminal tq1.
- the buffer circuit 40 is connected in parallel with the bridge circuit 14 .
- the terminal tq2 of the buffer switching element Q3 is connected to the connection point between the cathode of the upper arm diode 12 and the first end t31 of the upper arm switching element Q1.
- the terminal tc2 of the buffer capacitor Cc is connected to the connection point between the anode of the lower arm diode 13 and the second end t42 of the lower arm switching element Q2.
- the power conversion device 1 includes a current sensor C1 that detects current flowing through the first inductor 11 .
- the power conversion device 1 also includes a voltage sensor C2 that detects an input voltage and a voltage sensor C3 that detects an output voltage.
- Current sensor C ⁇ b>1 , voltage sensor C ⁇ b>2 , and voltage sensor C ⁇ b>3 output their detection results to control unit 50 .
- the control unit 50 turns ON/OFF both arm switching elements Q1 and Q2 and the buffer switching element Q3 based on the signals from the current sensor C1, voltage sensor C2 and voltage sensor C3.
- the power conversion device 1 converts the AC voltage supplied by the AC power supply V1 into a DC voltage by switching the conduction state and the non-conduction state of each of the switching elements Q1 to Q3, and converts the DC voltage to both output terminals t91 and t92. Output from
- a combination of the conductive state (ON state) or non-conductive state (OFF state) of each of the switching elements Q1 to Q3 is called a switching pattern.
- a first pattern P1, a second pattern P2, a third pattern P3, a fourth pattern P4, a fifth pattern P5, and a sixth pattern P6 are set as switching patterns.
- the control unit 50 performs switching control to repeatedly execute the unit operation at a predetermined cycle, with the operation of switching the switching pattern in the order of P1->P2->P3->P4->P5->P6->P1 as one unit.
- the first pattern P1 is a switching pattern in which the buffer switching element Q3 is in a non-conducting state and the upper arm switching element Q1 and the lower arm switching element Q2 are in a conducting state.
- the second pattern P2 is a switching pattern in which the upper arm switching element Q1 and the buffer switching element Q3 are non-conducting, and the lower arm switching element Q2 is conducting.
- a third pattern P3 is a switching pattern in which the upper arm switching element Q1 is in a non-conducting state, and the lower arm switching element Q2 and the buffer switching element Q3 are in a conducting state.
- the third pattern P3 corresponds to the "specific pattern”.
- a fourth pattern P4 is a switching pattern in which the upper arm switching element Q1 and the lower arm switching element Q2 are in a non-conducting state, and the buffer switching element Q3 is in a conducting state.
- the fourth pattern P4 corresponds to the "dead time pattern".
- a fifth pattern P5 is a switching pattern in which the lower arm switching element Q2 is in a non-conducting state and the upper arm switching element Q1 and the buffer switching element Q3 are in a conducting state.
- a sixth pattern P6 is a switching pattern in which the lower arm switching element Q2 and the buffer switching element Q3 are in a non-conducting state, and the upper arm switching element Q1 is in a conducting state.
- FIG. 1 In the AC power supply V1, a state in which the potential at the first terminal t11 is higher than the potential at the second terminal t12 is referred to as "positive AC potential state”. A state in which the potential of the first terminal t11 is lower than the potential of the second terminal t12 is referred to as "a state in which the AC potential is negative". Note that the state in which the AC potential is positive means that the AC voltage input from the AC power supply V1 has a positive polarity, and the state in which the AC potential is negative means that the AC voltage input from the AC power supply V1 has a negative polarity. It can also be said that
- the operation in the state where the alternating current potential is negative is the alternating current except that the operations of both arm switching elements Q1 and Q2 are switched corresponding to the reversal of the polarity and current flows through the upper arm diode 12 instead of the lower arm diode 13. This is the same as the positive potential state. Therefore, the state in which the AC potential is positive will be described below, and the description of the state in which the AC potential is negative will be omitted.
- each capacitor 17, 19, 23 shall be charged with each voltage. It is also assumed that currents flow through the first inductor 11, the primary winding W1 and the secondary winding W2 of the transformer 18, and the second inductor 21, respectively.
- the primary side circuit 10, the first capacitor 17 and the primary winding W1 are also referred to as the primary side of the power converter 1, and the secondary winding W2, the second capacitor 19 and the rectifying/smoothing circuit 20 are the secondary side of the power converter 1. Also called side.
- the control unit 50 repeatedly performs switching control to switch the switching pattern from the first pattern P1 to the first pattern P1 via each of the patterns P2 to P6 when the AC potential is in a positive state. As a result, the state of the power converter 1 transitions from the first state ⁇ 1 to the ninth state ⁇ 9. Details of each state will be described below.
- a first state ⁇ 1 shown in FIG. 1 is a state in which the control unit 50 controls the switching pattern to the first pattern P1.
- the primary side of the power conversion device 1 includes a current path ra1 associated with the supply of power from the AC power supply V1 and a current path ra2 associated with the discharge of the first capacitor 17. current flows through
- a current path ra1 is a path from the first end t11 of the AC power supply V1 to the second end t12 of the AC power supply V1 via the first inductor 11, the drain-source of the lower arm switching element Q2, and the lower arm diode 13. is.
- the current flowing through the current path ra1 increases with time in the direction from the AC power supply V1 toward the first inductor 11 .
- a current path ra2 passes from the first terminal t51 of the first capacitor 17, between the drain and source of the upper arm switching element Q1, between the drain and source of the lower arm switching element Q2, and from the end to the beginning of the primary winding W1. This is the path to the second end t52 of the first capacitor 17.
- FIG. The voltage across the first capacitor 17 is applied to the primary winding W1 of the transformer 18, and the potential at the terminal end of the primary winding W1 becomes higher than the potential at the starting end. As a result, a voltage is generated across the secondary winding W2 of the transformer 18 such that the terminal potential is higher than the starting potential.
- a current path rb1 is a current path generated by a voltage generated across secondary winding W2 of transformer 18 .
- a current path rb1 is a path from the end of the secondary winding W2 to the beginning of the secondary winding W2 via the second inductor 21 and the second capacitor 19 .
- a current path rb2 extends from a first end t81 of the output capacitor 23, a first output end t91, a load (not shown) connected to the power converter 1, and a second output end t92 of the output capacitor 23. This is the route up to the second end t82.
- a DC voltage which is the voltage across the output capacitor 23, is generated between the first output terminal t91 and the second output terminal t92. Discharge of the output capacitor 23 supplies current to the load. In the first state ⁇ 1, the secondary diode 22 is not conducting.
- a second state ⁇ 2 shown in FIG. 2 is a state in which the control unit 50 controls the switching pattern to the second pattern P2.
- a current flows through a current path ra1 and a current path ra3 due to the current continuity of the leakage inductance Rw1 of the primary winding W1. .
- a current path ra3 is a path from the leakage inductance Rw1 of the primary winding W1 to the leakage inductance Rw1 via the first capacitor 17, the body diode of the buffer switching element Q3, and the buffer capacitor Cc.
- the current flowing through the primary winding W1 flows through the body diode of the buffer switching element Q3 to the buffer capacitor Cc, charging the buffer capacitor Cc.
- the voltage across the buffer capacitor Cc is applied to the primary winding W1.
- the direction of the voltage applied to the primary winding W1 is reversed before and after being controlled to the second state ⁇ 2. Therefore, the current through primary winding W1 decreases rapidly.
- a current path rb3 is a path from the leakage inductance Rw2 of the secondary winding W2 through the second inductor 21 and the second capacitor 19 to the leakage inductance Rw2 of the secondary winding W2.
- the current flowing through the secondary winding W2 decreases as the current flowing through the primary winding W1 decreases.
- a current path rb4 includes a first path from the second inductor 21 to the load and a second path from the output capacitor 23 to the load.
- a first path of the current path rb4 is from the first end t71 of the second inductor 21, the secondary diode 22, the first output terminal t91, the load connected to the power converter 1, and the second output terminal t92. , to the second end t ⁇ b>72 of the second inductor 21 .
- a current begins to flow through the secondary diode 22 and increases.
- the primary side of the transformer 18 has a polarity such that the secondary side diode 22 becomes conductive.
- the winding W1 and the secondary winding W2 are magnetically coupled.
- a second path of the current path rb4 joins the first path from the output capacitor 23, and the discharge current of the output capacitor 23 flows toward the load.
- a third state ⁇ 3 shown in FIG. 3 is a state in which the control unit 50 controls the switching pattern to the third pattern P3.
- current flows through the primary side of the power converter 1 through the current path ra1 and the current path ra3′.
- the current path ra3' is such that the current path ra3, which was routed through the body diode of the buffer switching element Q3 in the second state ⁇ 2, is changed to route between the drain and source of the buffer switching element Q3 in the third state ⁇ 3.
- the resistance of the current path ra3' can be made smaller than that of the current path ra3.
- the current flowing through the current path ra1 continues to increase, and the current flowing through the primary winding W1 continues to decrease.
- the voltage across the buffer capacitor Cc is applied to the primary winding W1.
- the period of the second state ⁇ 2 may be a short period as long as the time for controlling the lower arm switching element Q2 to be completely non-conductive is secured.
- the switching elements Q1 to Q3 all become conductive and the buffer capacitor Cc is short-circuited.
- the period of the second state ⁇ 2 may be shorter than the period of the first state ⁇ 1 or the period of the third state ⁇ 3.
- a fourth state ⁇ 4 shown in FIG. 4 is a state in which a predetermined time has passed since the control unit 50 transitioned to the third state ⁇ 3. As shown in FIG. 4 , in the fourth state ⁇ 4, on the primary side of the power converter 1, current flows through the current path ra1 and the current path ra4.
- a current path ra4 is a path from the terminal tc1 of the buffer capacitor Cc to the terminal tc2 of the buffer capacitor Cc via the buffer switching element Q3, the first capacitor 17 and the primary winding W1.
- a current accompanying the discharge of the buffer capacitor Cc flows through the current path ra4. This changes the direction of the current flowing through the primary winding W1 and increases the current.
- the voltage across the buffer capacitor Cc is applied to the primary winding W1.
- Current path rb5 includes two paths. One is from the starting end of the secondary winding W2 via the second capacitor 19, the secondary diode 22, the first output terminal t91, the load connected to the power converter 1, and the second output terminal t92. This is the path to the end of the next winding W2. The other is from the first end t71 of the second inductor 21, the secondary side diode 22, the first output end t91, the load connected to the power conversion device 1, and the second inductor t92 via the second output end t92. 21 to the second end t72.
- the total current of the current flowing through the secondary winding W2 and the current flowing through the second inductor 21 flows through the secondary diode 22 .
- the current flowing through the second inductor 21 is substantially constant, while the current flowing through the secondary winding W2 increases. Therefore, the current flowing through the secondary diode 22 increases in the fourth state ⁇ 4. Further, part of the current flowing through the secondary diode 22 flows through the output capacitor 23 in the fourth state ⁇ 4. As a result, the output capacitor 23 is charged.
- a fifth state ⁇ 5 shown in FIGS. 5 and 6 is a state in which the control unit 50 controls the switching pattern to the fourth pattern P4.
- the direction of the current flowing through the buffer switching element Q3 and the buffer capacitor Cc differs according to the magnitude relationship between the current flowing through the first inductor 11 and the current flowing through the primary winding W1. Therefore, the fifth state ⁇ 5 when the current flowing through the first inductor 11 is larger than the current flowing through the primary winding W1 is referred to as the 5-1 state ⁇ 5(1).
- a fifth state ⁇ 5 in which the current flowing through the first inductor 11 is smaller than the current flowing through the primary winding W1 is defined as a 5-2 state ⁇ 5(2).
- the magnitude relationship between the current flowing through the first inductor 11 and the current flowing through the primary winding W1 at the time of transition to the fifth state ⁇ 5 may vary. Therefore, the fourth state ⁇ 4 may transit to the 5-1 state ⁇ 5(1), and the fourth state ⁇ 4 may transit to the 5-2 state ⁇ 5(2). Further, there may be a case where the 5-1 state ⁇ 5(1) transitions to the 5-2 state ⁇ 5(2) and then the 6th state ⁇ 6.
- a current path ra5-1 includes a first path and a second path.
- the first path is from the first inductor 11, the body diode of the upper arm switching element Q1, the first capacitor 17, the primary winding W1, the lower arm diode 13, the second input terminal t22, the AC power supply V1, the first input terminal t21. , to the first inductor 11 .
- a second path extends from the first inductor 11 to the body diode of the upper arm switching element Q1, the buffer switching element Q3, the buffer capacitor Cc, the lower arm diode 13, the second input terminal t22, the AC power supply V1, and the first input terminal t21. It is a route to the first inductor 11 via. A difference ⁇ I between the current flowing through the first inductor 11 and the current flowing through the primary winding W1 flows through the second path. This charges the buffer capacitor Cc.
- a sixth state ⁇ 6 shown in FIG. 7 is a state in which the control unit 50 controls the switching pattern to the fifth pattern P5. As shown in FIG. 7, in the sixth state ⁇ 6, on the primary side of the power conversion device 1, a current path ra5- 1' or current path ra5-2'.
- the current path ra5-1' is obtained by changing the current path ra5-1 through the body diode of the upper arm switching element Q1 to the drain-source of the upper arm switching element Q1. As a result, the resistance of the current path ra5-1' can be made smaller than that of the current path ra5-1.
- the current path ra5-2' is obtained by changing the current path ra5-2 through the body diode of the upper arm switching element Q1 to the drain-source of the upper arm switching element Q1. .
- the resistance of the current path ra5-2' can be made smaller than that of the current path ra5-2.
- the period of the fifth state ⁇ 5 (in other words, the period during which the switching pattern is the fourth pattern P4), the switching elements Q1 to Q3 are simultaneously turned on and the buffer capacitor Cc is short-circuited. time period. Therefore, the period of the fifth state ⁇ 5 may be a short period as long as the time for controlling the lower arm switching element Q2 to be completely non-conducting is ensured. In other words, during the transition period from the fourth state ⁇ 4 (third pattern P3) to the sixth state ⁇ 6 (fifth pattern P5), if all the switching elements Q1 to Q3 do not become conductive, the fifth state The period of ⁇ 5 may be shorter than the period of the fourth state ⁇ 4 or the period of the sixth state ⁇ 6.
- a seventh state ⁇ 7 shown in FIGS. 8 and 9 is a state in which the control unit 50 controls the switching pattern to the sixth pattern P6.
- the direction of the current flowing through the buffer switching element Q3 and the buffer capacitor Cc differs according to the magnitude relationship between the current flowing through the first inductor 11 and the current flowing through the primary winding W1. Therefore, the seventh state ⁇ 7 when the current flowing through the first inductor 11 is larger than the current flowing through the primary winding W1 is defined as the 7-1 state ⁇ 7(1), and the current flowing through the first inductor 11 is the primary winding W1.
- the seventh state ⁇ 7 when the current is smaller than the current flowing through W1 is referred to as the 7-2 state ⁇ 7(2).
- the magnitude relationship between the current flowing through the first inductor 11 and the current flowing through the primary winding W1 at the time of transition to the seventh state ⁇ 7 may vary. Therefore, the sixth state ⁇ 6 may transit to the 7-1 state ⁇ 7(1), and the sixth state ⁇ 6 may transit to the 7-2 state ⁇ 7(2). Further, there may be a case where the 7-1 state ⁇ 7(1) transitions to the 7-2 state ⁇ 7(2) and then the 8th state ⁇ 8.
- a current path ra6 includes a first path and a second path.
- a first path of the current path ra6 is from the first inductor 11, between the drain and source of the upper arm switching element Q1, the first capacitor 17, the primary winding W1, the lower arm diode 13, the second input terminal t22, and the AC power source V1. , to the first inductor 11 via the first input terminal t21.
- a second path of the current path ra6 is from the first inductor 11, between the drain and source of the upper arm switching element Q1, between the drain and source of the buffer switching element Q3, the buffer capacitor Cc, the lower arm diode 13, and the second input terminal t22. , the AC power supply V1, and the first input terminal t21 to the first inductor 11.
- a current path ra7 extends from the first inductor 11, the drain-source of the upper arm switching element Q1, the first capacitor 17, the primary winding W1, the lower arm diode 13, the second input terminal t22, the AC power supply V1, the first input It is a path to the first inductor 11 via the end t21.
- the difference ⁇ I between the current flowing through the first inductor 11 and the current flowing through the primary winding W1 passes through the body diode of the lower arm switching element Q2 to the upper arm switching element Q1. between the drain and source of the first capacitor 17 and the primary winding W1.
- the direction of the voltage applied to the primary winding W1 is reversed. As a result, the current flowing through the primary winding W1 begins to decrease.
- An eighth state ⁇ 8 shown in FIG. 10 is a state in which a predetermined time has passed since the control unit 50 controlled the switching pattern to the sixth pattern P6.
- the eighth state ⁇ 8 is a state in which the current flowing through the first inductor 11 matches the current flowing through the primary winding W1.
- the switching elements Q1 to Q3 are simultaneously turned on and the buffer capacitor Cc is short-circuited. It is a dead time period for suppression. Therefore, the periods of the seventh state ⁇ 7 and the eighth state ⁇ 8 may be short as long as the time for controlling the buffer switching element Q3 to be completely non-conductive is secured.
- the combined period of the seventh state ⁇ 7 and the eighth state ⁇ 8 is It may be shorter than the period of the sixth state ⁇ 6 or the ninth state ⁇ 9.
- a ninth state ⁇ 9 shown in FIG. 11 is a state immediately after the control unit 50 switches the switching pattern from the sixth pattern P6 to the first pattern P1.
- a current path ra8 extends from the leakage inductance Rw1 of the primary winding W1, the primary winding W1, the lower arm diode 13, the second input terminal t22, the AC power supply V1, the first input terminal t21, the first inductor 11, and the upper arm switching element. This is the path to the leakage inductance Rw1 via the first capacitor 17 between the drain and source of Q1.
- the current flowing through the first inductor 11 increases, while the current flowing through the primary winding W1 decreases. Further, on the primary side of the power converter 1, the difference ⁇ I between the current flowing through the first inductor 11 and the current flowing through the primary winding W1 flows through the lower arm switching element Q2.
- Current path rb6 includes two paths. One is the leakage inductance Rw2 of the secondary winding W2, the second capacitor 19, the secondary diode 22, the first output terminal t91, the load connected to the power converter 1, the second output terminal t92 and the secondary This is the path to the leakage inductance Rw2 via the winding W2. The other is from the first end t71 of the second inductor 21, the secondary diode 22, the first output end t91, the load connected to the power converter 1, the second output end t92 and the secondary winding W2. It is a path to the second end t72 of the second inductor 21 via.
- the ninth state ⁇ 9 the current flowing through the primary winding W1 decreases, so the current flowing through the secondary winding W2 decreases. Therefore, the current flowing through the secondary diode 22 is reduced. Also, in the ninth state ⁇ 9, part of the current flowing through the secondary diode 22 flows through the output capacitor 23 . As a result, the output capacitor 23 is charged.
- the direction of the current flowing through the primary winding W1 is reversed.
- the direction of the current flowing through the secondary winding W2 is reversed.
- the difference ⁇ I between the current flowing through the secondary winding W2 and the current flowing through the second inductor 21 flows through the secondary diode 22, and the current flowing through the secondary diode 22 continues to decrease.
- the current flowing through the secondary diode 22 ceases and the state returns to the first state ⁇ 1.
- the third pattern P3 when the AC potential is negative is a switching pattern in which the lower arm switching element Q2 is in a non-conducting state and the upper arm switching element Q1 and the buffer switching element Q3 are in a conducting state. That is, when the AC voltage input from the AC power supply V1 has a negative polarity, the control unit 50 of the present embodiment performs switching control for sequentially switching a plurality of switching patterns including the third pattern P3.
- the third pattern P3 is such that one of the two arm switching elements Q1 and Q2 is in a non-conducting state and the other of the two arm switching elements Q1 and Q2 and the buffer switching are switched. It can be said that this is a switching pattern in which the element Q3 is in a conducting state.
- FIG. 12 is a graph showing the state of each switching element Q1-Q3 and the change of each current during one cycle.
- IL1 indicates the current flowing through the first inductor 11
- IQ1-IQ3 indicate the currents flowing through the switching elements Q1-Q3
- Ip indicates the current flowing through the primary winding W1
- Is indicates the secondary winding W2.
- Id indicates the current flowing through the secondary diode 22 .
- FIG. 12 shows a case of transition from the sixth state ⁇ 6 to the 7-2 state ⁇ 7(2).
- the switching patterns of the switching elements Q1 to Q3 are sequentially switched from the first pattern P1 to the first pattern P1 via the patterns P2 to P6, so that the power conversion device 1 changes from the first state ⁇ 1 to the Transitions are made sequentially up to the ninth state ⁇ 9. Thereby, power conversion is performed in the power conversion device 1 . That is, the AC voltage of the AC power supply V1 is converted into a DC voltage.
- the buffer circuit 40 suppresses the generation of surge voltage by causing the currents of the two inductors to flow through the buffer capacitor Cc.
- the buffer circuit 40 absorbs the difference ⁇ I between the current flowing through the first inductor 11 and the current flowing through the primary winding W1, and discharges the absorbed energy appropriately.
- the lower arm switching element Q2 and the buffer switching element Q3 are in the conducting state from the first state ⁇ 1 via the second state ⁇ 2 which is the dead time. Transition to state ⁇ 3.
- the voltage across the buffer capacitor Cc is applied to the primary winding W1, and current begins to flow through the secondary diode 22.
- the lower arm switching element Q2 is in a conductive state, a period during which current flows through the secondary diode 22 can be provided.
- the period from the second state ⁇ 2 to the sixth state ⁇ 6 is set so that the amount of current flowing through the secondary diode 22 (charge passing through the secondary diode 22) during one cycle is constant. good too.
- the ripple component of the output voltage can be reduced.
- the controller 50 can control switching based on the current flowing through the first inductor 11 and the input voltage so as to improve the power factor of the input power.
- the control unit 50 operates the bridge circuit 14 as a power factor correction (PFC) circuit by controlling the times of the first state ⁇ 1 and the ninth state ⁇ 9.
- PFC power factor correction
- the AC power supply V1 and the first inductor 11 form a closed circuit, and the current from the AC power supply V1 is limited by the first inductor 11 .
- the control unit 50 controls the current sensor C1 and the voltage sensor C2 so that the waveform of the current flowing through the first inductor 11 becomes substantially sinusoidal, and the frequency and phase of the sinusoidal wave match the frequency and phase of the AC power supply V1. to control the duration of the first state ⁇ 1 and the ninth state ⁇ 9 based on signals from .
- the buffer switching element Q3 becomes conductive.
- the period depends on the PFC operation. Therefore, it is difficult to control the amount of current passing through the secondary diode 22 because it is difficult to adjust the period during which the buffer switching element Q3 is in the conductive state.
- the third pattern P3 is set as the specific pattern, it is easy to adjust the period during which the buffer switching element Q3 is in the conductive state. Thereby, the amount of current passing through the secondary diode 22 can be controlled while performing the PFC operation. Therefore, it is possible to improve the power factor and reduce ripples in the output voltage.
- the control unit 50 can also perform switching control so that a predetermined DC voltage is output based on the detection result of the voltage sensor C3. Specifically, the control unit 50 performs duty ratio control of both arm switching elements Q1 and Q2 based on, for example, the difference between the output voltage detected by the voltage sensor C3 and a predetermined DC voltage (target voltage). Furthermore, the control unit 50 can simultaneously improve the power factor of the input power and control the output voltage.
- the power conversion device 1 transits to the first state ⁇ 1 to the ninth state ⁇ 9 by the control unit 50 controlling the switching of the switching elements Q1 to Q3 according to the polarity of the AC power supply V1. Thereby, the bridge circuit 14 converts the AC voltage of the AC power supply V1 into a DC voltage.
- the power converter 1 can reduce the number of active elements such as switching elements and rectifying elements compared to the case of using a full bridge circuit like the circuit of the power converter of Patent Document 1.
- the power conversion device 1 of the present embodiment has a smaller number of active elements through which current passes than when a full bridge circuit is used as in the power conversion device of Patent Document 1, so the conduction loss in the active elements can be reduced.
- the control unit 50 has a plurality of patterns P1 to P6 as switching patterns that are combinations of the states of the switching elements Q1 to Q3.
- the control unit 50 controls switching so as to sequentially switch among the plurality of patterns P1 to P6 including the third pattern P3 as the specific pattern.
- a third pattern P3 is a switching pattern in which one of the two arm switching elements Q1 and Q2 is non-conductive, and the other of the two arm switching elements Q1 and Q2 and the buffer switching element Q3 are conductive. As a result, it is possible to adjust the period during which the voltage across the buffer capacitor Cc is applied to the primary winding W1. amount of charge) can be controlled.
- ripples in the output voltage can be reduced.
- One of the causes of output voltage ripple is the difference between input power and output power.
- the PFC operation controls the input current into a sinusoidal waveform that matches the frequency and phase of the input voltage
- the input power changes sinusoidally at twice the frequency of the input voltage.
- the output power is often controlled to be constant, and the difference between the input power and the output power changes over time.
- the amount of current flowing through the secondary diode 22 is not controlled, the surplus is stored in the output capacitor 23 when the input power is excessive, and the shortage is discharged from the output capacitor 23 when the input power is insufficient. Therefore, a ripple occurs in the output voltage.
- control parameters of the power conversion device 1 can be set to two, the duty of the upper arm switching element Q1 or the lower arm switching element Q2 and the duty of the buffer switching element Q3. can.
- the output voltage ripple can be reduced while maintaining the performance of power factor control and output voltage control.
- the third pattern P3 is such that the upper arm switching element Q1 is in a non-conducting state and the lower arm switching element Q2 and the buffer switching element Q3 are in a conducting state. switching pattern.
- the third pattern P3 is such that the lower arm switching element Q2 is in a non-conducting state and the upper arm switching element Q1 and the buffer switching element Q3 are in a conducting state. switching pattern.
- Circuit 40 provides a bypass path for both currents.
- the power converter 1 uses the buffer circuit 40 to reduce the surge voltage that can occur due to the mismatch between the continuity of the current of the first inductor 11 and the continuity of the current of the leakage inductance Rw1 of the transformer 18. can be suppressed.
- the transformer 18 transfers power from the primary side to the secondary side in all of the second state ⁇ 2 to the ninth state ⁇ 9 regardless of the direction of the voltage applied to the starting end and the terminal end of the primary winding W1 of the transformer 18. to communicate. Therefore, the power converter 1 can improve the utilization efficiency of the transformer 18 .
- the buffer circuit 40 has a buffer switching element Q3 provided between both arm switching elements Q1, Q2 and the buffer capacitor Cc. According to this configuration, when the current flowing through the first inductor 11 is larger than the current flowing through the primary winding W1, not only is the buffer capacitor Cc charged with the difference ⁇ I, but also the current flows from the buffer capacitor Cc to the primary winding W1. can also be supplied. As a result, the buffer capacitor Cc can be discharged appropriately to suppress the rise in the voltage across the buffer capacitor Cc, and the energy from the AC power supply V1 can be output through the transformer 18 without waste.
- a switching element for example, MOSFET
- MOSFET MOSFET
- the resistance of the buffer switching element Q3 can be lowered by making the buffer switching element Q3 conductive. Therefore, it is possible to suppress heat generation due to the flow of surge voltage, as compared with the case of using only diodes.
- the discharge from the buffer capacitor Cc can be controlled.
- the buffer switching element Q3 is in a conductive state, so that the discharge current of the buffer capacitor Cc can flow through the primary winding W1.
- the control unit 50 controls switching so as to improve the power factor based on the current flowing through the first inductor 11 and the input voltage from the AC power supply V1. With such a configuration, the power converter 1 can improve the power factor of the power supplied from the AC power supply V1.
- control unit 50 Based on the voltage between the first output terminal t91 and the second output terminal t92, the control unit 50 controls the upper arm switching element Q1 and the lower arm switching element Q2 so that a predetermined DC voltage is output. and the switching of the buffer switching element Q3.
- the power conversion device 1 performs feedback control based on the voltage between the first output end t91 and the second output end t92, and the DC voltage output by the power conversion device 1 is reduced to a predetermined DC voltage (target voltage).
- the above embodiment may be modified as follows. Note that the above embodiment and each of the following examples may be combined with each other within a technically consistent range.
- the switching patterns other than the dead time are not limited to the first pattern P1, the third pattern P3, and the sixth pattern P6. For example, when the AC voltage is positive, only the upper arm switching element Q1 is turned on, and when the AC voltage is negative, only the lower arm switching element Q2 is turned on. You may set it other than time. That is, as the specific pattern, a pattern in which one of the two arm switching elements Q1 and Q2 is conductive and the other of the two arm switching elements Q1 and Q2 and the buffer switching element Q3 is non-conductive may be adopted.
- the first state ⁇ 1 may be continued until the AC voltage is positive and the lower arm switching element Q2 becomes non-conductive. In this case, when the lower arm switching element Q2 becomes non-conductive, only the upper arm switching element Q1 becomes conductive (in other words, a specific pattern is obtained).
- the current of the first inductor 11 flows back to the first inductor 11 through the upper arm switching element Q1, the body diode of the buffer switching element Q3, the buffer capacitor Cc, the lower arm diode 13, and the AC power supply V1.
- the current of the leakage inductance Rw1 of the primary winding W1 flows through the first capacitor 17, the body diode of the buffer switching element Q3, the buffer capacitor Cc, and returns to the primary winding W1.
- the voltage across the buffer capacitor Cc is applied to the primary winding W1, and a voltage opposite to that before the lower arm switching element Q2 becomes non-conductive is applied to the primary winding W1, so the current flowing through the primary winding W1 decreases. As a result, current begins to flow through the secondary diode 22 .
- This switching pattern may occur when the input voltage is low when the bridge circuit 14 is controlled to perform PFC operation. After the switching pattern, the fifth state ⁇ 5 is reached by turning on the buffer switching element Q3.
- both arm switching elements Q1 and Q2 are switched corresponding to the reversal of the polarity, and the current flows through the upper arm diode 12 instead of the lower arm diode 13. This is the same as when the AC potential is positive.
- the connection of the primary side circuit 10, the first capacitor 17, the transformer 18, and the buffer circuit 40 may be different from the above embodiment.
- the starting end of the primary winding W1 is electrically connected to the cathode of the upper arm diode 12 and the first end t31 of the upper arm switching element Q1.
- a terminal end of the primary winding W1 is connected to a first terminal t51 of the first capacitor 17, and a second terminal t52 of the first capacitor 17 is connected to the cathode of the lower arm diode 13 and the second terminal of the lower arm switching element Q2. It is connected to the end t42.
- the terminal tq2 of the buffer switching element Q3 is connected to the connection point between the bridge circuit 14 (specifically, the cathode of the upper arm diode 12 and the first terminal t31) and the starting end of the primary winding W1.
- the terminal tc2 of the buffer capacitor Cc is connected to the terminal end of the primary winding W1 and the first end t51 of the first capacitor 17 .
- the buffer capacitor Cc is connected in series with the first capacitor 17 .
- control unit 50 sequentially switching the switching pattern from the first pattern P1 to the first pattern P1 via the patterns P2 to P6.
- the buffer capacitor Cc is connected in series with the first capacitor 17 . Therefore, in the second state ⁇ 2 to the third state ⁇ 3, the buffer capacitor Cc and the first capacitor 17 have both the current continuity of the first inductor 11 and the current continuity of the leakage inductance Rw1 of the transformer 18. Provide a detour path for both currents so as to ensure the continuity of That is, according to the power conversion device 2, the combination of the buffer capacitor Cc and the first capacitor 17 can suppress the surge voltage.
- the voltage applied across the buffer capacitor Cc in the power converter 1 is divided into the voltage applied to the first capacitor 17 and the voltage applied to the buffer capacitor Cc. be done. Thereby, the breakdown voltage of the buffer capacitor Cc can be made smaller than that of the buffer capacitor Cc used in the power converter 1 .
- the position where the terminal tc2 of the buffer capacitor Cc is connected is not limited to this, and may be connected to the lower arm side of the bridge circuit 14 (more specifically, the lower arm diode 13 and the second end t42). However, in this case, the voltage applied to the buffer capacitor Cc is the same as in the power converter 1 .
- the second capacitor 19 is connected between the starting end of the secondary winding W2 and the cathode of the secondary diode 22, but the position of the second capacitor 19 is not limited to this. It may be connected between the end of line W2 and the anode of secondary diode 22 . Also, the second capacitor 19 may be composed of two capacitors. It is connected both between the cathodes of the side diodes 22 .
- the rectifying/smoothing circuit 30 includes a second inductor 21, a secondary diode 22, an output capacitor 23, a first output line OL1, a second output line OL2, a first output terminal t91, and a second output terminal t92. and
- the end of the secondary winding W2 is electrically connected to the first end t71 of the second inductor 21 and the cathode of the secondary diode 22 via the second capacitor 19.
- the terminal end of the secondary winding W2 is connected to the first end t61 of the second capacitor 19, and the second end t62 of the second capacitor 19 is connected to the first end t71 of the second inductor 21. It is connected to the cathode of the secondary diode 22 .
- a starting end of the secondary winding W2 is connected to the anode of the secondary diode 22 and the second output line OL2. Therefore, the rectifying/smoothing circuit 30 is connected to the secondary winding W2 of the transformer 18 via the second capacitor 19. As shown in FIG.
- the cathode of the secondary diode 22 is an example of "one end of the secondary rectifying element, that is, the first end", and the anode of the secondary diode 22 is "other than the secondary rectifying element". It is an example of an end, i.e., second end.
- the polarity of the secondary winding W2 is reversed. Specifically, the starting ends of the primary winding W1 and the secondary winding W2 are reversed.
- the output capacitor 23 is connected to both the first output line OL1 and the second output line OL2. Specifically, the first end t81 of the output capacitor 23 is connected to the first output line OL1. The first output line OL1 is connected to the first output terminal t91. Therefore, it can be said that the first end t81 of the output capacitor 23 is connected to the first output end t91. A second end t82 of the output capacitor 23 is connected to the second output line OL2. The second output line OL2 is connected to the second output terminal t92. Therefore, it can be said that the second end t82 of the output capacitor 23 is connected to the second output end t92.
- a second end t72 of the second inductor 21 is connected to the first output line OL1.
- the first end t71 of the second inductor 21 and the cathode of the secondary diode 22 are connected.
- the second end t72 of the second inductor 21 and the first end t81 of the output capacitor 23 are connected. Therefore, the cathode of the secondary diode 22 is connected to the first end t81 of the output capacitor 23 through the second inductor 21.
- the anode of the secondary diode 22 is connected to the second end t82 of the output capacitor 23. As shown in FIG.
- the secondary diode 22 conducts when one of the two arm switching elements Q1 and Q2 is in a non-conducting state. That is, the primary winding W1 and the secondary winding W2 are magnetically coupled so that the secondary diode 22 conducts when one of the two arm switching elements Q1 and Q2 is in a non-conducting state. is doing. Even in such a configuration, similar effects can be obtained by performing the switching control described above by the control unit 50 .
- the power conversion device 4 may be different from the power conversion device 3 in connection of the primary side circuit 10, the first capacitor 17, the transformer 18 and the buffer circuit 40.
- the starting end of the primary winding W1 is electrically connected to the cathode of the upper arm diode 12 and the first end t31 of the upper arm switching element Q1.
- a terminal end of the primary winding W1 is connected to a first terminal t51 of the first capacitor 17, and a second terminal t52 of the first capacitor 17 is connected to the anode of the lower arm diode 13 and the second terminal of the lower arm switching element Q2. It is connected to the end t42.
- the terminal tq2 of the buffer switching element Q3 is connected to the connection point between the bridge circuit 14 (specifically, the cathode of the upper arm diode 12 and the first terminal t31) and the starting end of the primary winding W1.
- the terminal tc2 of the buffer capacitor Cc is connected to the terminal end of the primary winding W1 and the first end t51 of the first capacitor 17 .
- the buffer capacitor Cc is connected in parallel with the primary winding W1 of the transformer 18 via the buffer switching element Q3.
- the buffer capacitor Cc is connected in series with the first capacitor 17 . Even in such a configuration, similar effects can be obtained by performing the switching control described above by the control unit 50 .
- a power conversion device 5 having a configuration on the secondary side different from that of the power conversion device 1 may be used.
- the power conversion device 5 includes a primary side circuit 10 , a first capacitor 17 , a transformer 18 a , a buffer circuit 40 , a control section 50 and a rectifying/smoothing circuit 60 .
- the transformer 18a includes a first secondary winding W21 and a second secondary winding W22 as the secondary winding W2.
- the rectifying/smoothing circuit 60 includes a second inductor 21, an output capacitor 23, a first secondary diode 24, a second secondary diode 25, a first output line OL1, a second output line OL2, and a second output line OL2. It has a first output terminal t91 and a second output terminal t92.
- the starting end of the first secondary winding W21 is electrically connected to the anode of the first secondary diode 24.
- a terminal end of the second secondary winding W22 is electrically connected to the anode of the second secondary diode 25 .
- the cathode of the first secondary diode 24 is connected through the second inductor 21 to one end of the output capacitor 23, that is, the first end.
- the anode of the first secondary diode 24 is connected to the first end t71 of the second inductor 21 .
- the cathode of the second secondary diode 25 is connected to the connection point between the cathode of the first secondary diode 24 and the first end t71.
- the terminal end of the first secondary winding W21 and the starting end of the second secondary winding W22 are connected.
- the first secondary diode 24 and the second secondary diode 25 are connected as described above so that the current flowing through the first secondary winding W21 and the current flowing through the second secondary winding W22 respectively. Allow one of the currents and limit the other. Specifically, when the potential at the starting end of the primary winding W1 is higher than the potential at the terminating end of the primary winding W1, the first secondary diode 24 is connected from the first secondary winding W21 of the secondary winding W2 to the second inductor 21 and beyond. allow current to flow through Also, the second secondary diode 25 inhibits current from flowing from the second secondary winding W22 of the secondary winding W2 to the second inductor 21 and beyond.
- the second secondary diode 25 flows from the second secondary winding W22 of the secondary winding W2 to the second inductor 21 and beyond. allow. Also, the first secondary diode 24 inhibits current from flowing from the first secondary winding W21 of the secondary winding W2 to the second inductor 21 and beyond.
- the first secondary diode 24 is an example of the "first secondary rectifier", and the cathode of the first secondary diode 24 is "one end of the first secondary rectifier, That is, the anode of the first secondary side diode 24 is an example of "the other end of the first secondary side rectifying element, that is, the second end”.
- the second secondary diode 25 is an example of a "second secondary rectifier”, and the cathode of the second secondary diode 25 is "one end of the second secondary rectifier, that is, the first
- the anode of the second secondary side diode 25 is an example of "the other end of the second secondary side rectifying element, that is, the second end”.
- the output capacitor 23 is connected to both the first output line OL1 and the second output line OL2. Specifically, the first end t81 of the output capacitor 23 is connected to the first output line OL1. A second end t82 of the output capacitor 23 is connected to the second output line OL2.
- the second inductor 21 is provided between the first secondary diode 24 and the output capacitor 23 on the first output line OL1. Specifically, the second inductor 21 is provided at a portion between the connection point of the first secondary diode 24 and the connection point of the output capacitor 23 on the first output line OL1. As described above, the cathode of first secondary diode 24 and the cathode of second secondary diode 25 are connected to first end t71 of second inductor 21 . Also, the second end t72 of the second inductor 21 and the first end t81 of the output capacitor 23 are connected.
- a connection point between the first secondary winding W21 and the second secondary winding W22 is connected to the second end t82 of the output capacitor 23 and the second output line OL2.
- the connection point between the first secondary winding W21 and the second secondary winding W22 is, for example, the middle point of the secondary winding W2. Therefore, the second end t82 of the output capacitor 23 is connected to the middle point of the secondary winding W2.
- the secondary diode 22 becomes conductive when either one of the two arm switching elements Q1 and Q2 is in a non-conducting state. That is, the primary winding W1 and the secondary winding W2 are magnetically coupled so that the secondary diode 22 conducts when one of the two arm switching elements Q1 and Q2 is in a non-conducting state. is doing. Even in such a configuration, similar effects can be obtained by performing the switching control described above by the control unit 50 .
- the first secondary winding W21 and the second secondary winding W21 and the second secondary winding W21 are controlled by the first secondary diode 24 and the second secondary diode 25 according to the direction of the current flowing through the primary winding W1.
- the current flowing through the next winding W22 is switched.
- the second capacitor 19 can be omitted.
- the power electronics device 5 and the power electronics device 2 may be combined.
- the power conversion device 6 has a configuration similar to that of the power conversion device 5, while the connections of the primary side circuit 10, the first capacitor 17, the transformer 18 and the buffer circuit 40 are connected to provide power. It differs from the conversion device 5 .
- the starting end of the primary winding W1 is electrically connected to the cathode of the upper arm diode 12 and the first end t31 of the upper arm switching element Q1.
- a terminal end of the primary winding W1 is connected to a first terminal t51 of the first capacitor 17, and a second terminal t52 of the first capacitor 17 is connected to the anode of the lower arm diode 13 and the second terminal of the lower arm switching element Q2. It is connected to the end t42.
- the terminal tq2 of the buffer switching element Q3 is connected to the connection point between the bridge circuit 14 (specifically, the cathode of the upper arm diode 12 and the first terminal t31) and the starting end of the primary winding W1.
- the terminal tc2 of the buffer capacitor Cc is connected to the terminal end of the primary winding W1 and the first end t51 of the first capacitor 17 .
- the buffer capacitor Cc is connected in parallel with the primary winding W1 of the transformer 18 via the buffer switching element Q3.
- the buffer capacitor Cc is connected in series with the first capacitor 17 . Even in such a configuration, similar effects can be obtained by performing the switching control described above by the control unit 50 . Further, according to the power conversion device 6, the withstand voltage of the buffer capacitor Cc can be reduced, and the second capacitor 19 can be omitted.
- the present invention is not limited to this, and switching elements may be used instead of the diodes.
- the control unit 50 performs so-called synchronous rectification control to turn on the switching element at the timing when the upper arm diode 12 and the lower arm diode 13 become conductive. Conduction loss can be reduced by using switching elements instead of diodes.
- the rectifying/smoothing circuit 20 and the rectifying/smoothing circuit 30 include the secondary diode 22 as the secondary rectifying element, and the rectifying/smoothing circuit 60 includes the first secondary diode 24 as the secondary rectifying element. and the second secondary diode 25, but this is not the only option.
- the rectifying/smoothing circuit 20 and the rectifying/smoothing circuit 30 may have switching elements instead of the secondary diodes 22 .
- the rectifying/smoothing circuit 60 may have a switching element instead of the first secondary diode 24 and the second secondary diode 25 .
- the control unit 50 performs so-called synchronous rectification control to turn on the switching elements in a switching pattern state in which the secondary diode 22, the first secondary diode 24, and the second secondary diode 25 are conductive. conduct.
- the rectifying/smoothing circuit 20, the rectifying/smoothing circuit 30, and the rectifying/smoothing circuit 60 can reduce conduction loss by using switching elements instead of diodes.
- the first inductor 11 is connected between the first input terminal t21 and the first connection line CL1, but the position of the first inductor 11 is not limited to this. It may be connected between the connection line CL2. Further, the first inductor 11 is assumed to be two inductors, and is connected between both the first input terminal t21 and the first connection line CL1 and between the second input terminal t22 and the second connection line CL2. good too.
- the first capacitor 17 is connected between the starting end of the primary winding W1 and the first end t31 of the upper arm switching element Q1, but the position of the first capacitor 17 is not limited to this.
- the first capacitor 17 may be connected between the terminal end of the primary winding W1 and the second end t42 of the lower arm switching element Q2.
- the first capacitor 17 may be composed of two capacitors. In this case, the two capacitors are connected between the starting end of the primary winding W1 and the first end t31 of the upper arm switching element Q1, and between the terminal end of the primary winding W1 and the second end t42 of the lower arm switching element Q2. It is preferable that it is provided in between.
- the second capacitor 19 is connected between the starting end of the secondary winding W2 and the anode of the secondary diode 22, but the position of the second capacitor 19 is not limited to this.
- the second capacitor 19 may be connected between the terminal end of the secondary winding W2 and the second end t72 of the second inductor 21.
- the second capacitor 19 may be composed of two capacitors. In this case, the two capacitors are located between the beginning of the secondary winding W2 and the anode of the secondary diode 22 and between the end of the secondary winding W2 and the second end t72 of the second inductor 21. may be provided in
- the current sensor C1 may be provided on the second intermediate line ML2 instead of on the first intermediate line ML1.
- the control unit 50 can be configured as a circuit including one or more processors that execute various processes according to a computer program (software). Note that the control unit 50 may be configured as a circuit including one or more dedicated hardware circuits such as an application specific integrated circuit (ASIC) that executes at least part of the various types of processing. It may be configured as a circuit including a combination of one or more processors and one or more dedicated hardware circuits as described above.
- the processor includes a CPU and memory such as RAM and ROM. Memory, a non-transitory computer-readable storage medium, stores program code or instructions configured to cause a CPU to perform processes. Memory includes any medium that can be accessed by a general purpose or special purpose computer.
- the control unit switches the lower arm switching element to the non-conducting state and the upper arm switching element to the non-conducting state through a dead time pattern in which the buffer switching element is in the conducting state and the both arm switching elements are in the non-conducting state. Switching to a switching pattern in which the switching element and the buffer switching element are conductive may be performed.
- control unit switches the upper arm switching element to the non-conducting state and the lower arm switching element to the non-conducting state through a dead time pattern in which the buffer switching element is in the conducting state and the both arm switching elements are in the non-conducting state. Switching to a switching pattern in which the switching element and the buffer switching element are conductive may be performed.
- a power conversion device that converts an AC voltage input from an AC power supply into a DC voltage, wherein a transformer having a primary winding and a secondary winding, a first capacitor, and the AC power supply are connected.
- a primary side circuit having a pair of input terminals, a first inductor, an upper arm switching element, a lower arm switching element, an upper arm rectifying element, and a lower arm rectifying element, a second inductor, and a secondary side a rectifying/smoothing circuit having a rectifying element, an output capacitor, a first output terminal and a second output terminal, wherein the upper arm switching element and the lower arm switching element are connected in series; and the upper arm rectifying element.
- the primary side circuit includes a buffer circuit having a buffer switching element and a buffer capacitor, the primary side circuit including the first capacitor.
- the rectifying/smoothing circuit is connected to the secondary winding of the transformer, and the power conversion device includes the upper arm switching element and the lower arm switching element. and a control section configured to control switching of the buffer switching element, the control section setting any one of the two arm switching elements to be in a conductive state and the other of the two arm switching elements and the buffer switching element.
- a power conversion device that controls switching so as to sequentially switch between a plurality of switching patterns including a specific pattern in which a buffer switching element is in a non-conducting state.
- the switching pattern by setting the switching pattern to a specific pattern, the voltage of the buffer capacitor can be applied to the primary winding. Thereby, a current can flow through the secondary side rectifying element.
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Abstract
Description
かかる構成によれば、電力変換装置は、サージ電圧の発生を抑制できる。
かかる構成によれば、電力変換装置は、サージ電圧を抑制できる。また、電力変換装置は、バッファキャパシタに印加される電圧を低くできる。
[一次側回路10について]
一次側回路10は、例えば、第1インダクタ11と、上アームダイオード12と、下アームダイオード13と、上アームスイッチング素子Q1と、下アームスイッチング素子Q2と、第1接続線CL1と、第2接続線CL2と、第1中間線ML1と、第2中間線ML2と、第1入力端t21と、第2入力端t22と、バッファ回路40とを備える。上アームダイオード12は「上アーム整流素子」の一例であり、下アームダイオード13は「下アーム整流素子」の一例である。
整流平滑回路20は、第2インダクタ21と、二次側ダイオード22と、出力キャパシタ23と、第1出力線OL1と、第2出力線OL2と、第1出力端t91と、第2出力端t92とを備える。第2インダクタ21は、第1端t71と、第2端t72とを有し、出力キャパシタ23は、第1端t81と、第2端t82とを有する。二次側ダイオード22は、「二次側整流素子」の一例である。また、第1端t81は、「出力キャパシタの一端、即ち第1端」の一例であり、第2端t82は、「出力キャパシタの他端、即ち第2端」の一例である。
即ち第2端」の一例である。
バッファ回路40は、バッファスイッチング素子Q3と、バッファキャパシタCcと、第3接続線CL3とを備える。バッファスイッチング素子Q3と、バッファキャパシタCcとは、第3接続線CL3によって直列に接続されている。バッファスイッチング素子Q3は、端子tq1と、端子tq2とを有し、バッファキャパシタCcは、端子tc1と、端子tc2とを有する。バッファスイッチング素子Q3の端子tq1と、バッファキャパシタCcの端子tc1とは、第3接続線CL3によって接続されている。バッファスイッチング素子Q3は、ボディダイオードを有している。バッファスイッチング素子Q3のボディダイオードのアノードは、端子tq2に接続され、バッファスイッチング素子Q3のボディダイオードのカソードは、端子tq1に接続されている。
図1に示すように、電力変換装置1は、第1インダクタ11に流れる電流を検出する電流センサC1を備えている。また、電力変換装置1は、入力電圧を検出する電圧センサC2と、出力電圧を検出する電圧センサC3とを備えている。電流センサC1、電圧センサC2及び電圧センサC3は、その検出結果を制御部50に出力する。
図1に示す第1状態Φ1は、制御部50がスイッチングパターンを第1パターンP1に制御した状態である。図1に示すように、第1状態Φ1において、電力変換装置1の一次側には、交流電源V1からの電力の供給に伴う電流経路ra1と、第1キャパシタ17の放電に伴う電流経路ra2とに電流が流れる。
図2に示す第2状態Φ2は、制御部50がスイッチングパターンを第2パターンP2に制御した状態である。図2に示すように、第2状態Φ2において、電力変換装置1の一次側には、電流経路ra1と、一次巻線W1の漏れインダクタンスRw1の電流の連続性による電流経路ra3とに電流が流れる。
図3に示す第3状態Φ3は、制御部50がスイッチングパターンを第3パターンP3に制御した状態である。図3に示すように、第3状態Φ3において、電力変換装置1の一次側には、電流経路ra1と、電流経路ra3′とに電流が流れる。電流経路ra3′は、第2状態Φ2においてバッファスイッチング素子Q3のボディダイオードを経由していた電流経路ra3が、第3状態Φ3では、バッファスイッチング素子Q3のドレイン-ソース間経由に替わったものである。これにより、電流経路ra3と比較して、電流経路ra3′の抵抗を小さくすることができる。なお、第3状態Φ3においても、電流経路ra1に流れる電流は増加を継続し、一次巻線W1を流れる電流は減少を継続する。第3状態Φ3でも、一次巻線W1には、バッファキャパシタCc両端の電圧が印加される。
図4に示す第4状態Φ4は、制御部50が第3状態Φ3に遷移してから所定の時間が経過した状態である。図4に示すように、第4状態Φ4において、電力変換装置1の一次側には、電流経路ra1と、電流経路ra4とに電流が流れる。
図5及び図6に示す第5状態Φ5は、制御部50がスイッチングパターンを第4パターンP4に制御した状態である。第5状態Φ5は、第1インダクタ11に流れる電流と一次巻線W1に流れる電流との大小関係に応じて、バッファスイッチング素子Q3及びバッファキャパシタCcに流れる電流の向きが異なる。このため、第1インダクタ11に流れる電流が一次巻線W1に流れる電流よりも大きい場合の第5状態Φ5を、第5-1状態Φ5(1)とする。そして、第1インダクタ11に流れる電流が一次巻線W1に流れる電流よりも小さい場合の第5状態Φ5を、第5-2状態Φ5(2)とする。
図5に示すように、第5-1状態Φ5(1)において、電力変換装置1の一次側には、電流経路ra5-1に電流が流れる。
図6に示すように、第5-2状態Φ5(2)において、電力変換装置1の一次側には、電流経路ra5-2に電流が流れる。電流経路ra5-2は、第1経路及び第2経路を含む。電流経路ra5-2の第1経路は、電流経路ra5-1の第1経路と同じである。電流経路ra5-2の第2経路は、バッファキャパシタCcから、バッファスイッチング素子Q3、第1キャパシタ17、一次巻線W1を経由して、バッファキャパシタCcにもどる経路である。バッファキャパシタCcが放電することにより、第2経路には、第1インダクタ11を流れる電流と一次巻線W1に流れる電流との差分δIが流れる。
図7に示す第6状態Φ6は、制御部50がスイッチングパターンを第5パターンP5に制御した状態である。図7に示すように、第6状態Φ6において、電力変換装置1の一次側には、第1インダクタ11に流れる電流と一次巻線W1に流れる電流との大小関係に応じて、電流経路ra5-1′または電流経路ra5-2′に電流が流れる。
図8及び図9に示す第7状態Φ7は、制御部50がスイッチングパターンを第6パターンP6に制御した状態である。第7状態Φ7は、第1インダクタ11に流れる電流と一次巻線W1に流れる電流との大小関係に応じて、バッファスイッチング素子Q3及びバッファキャパシタCcに流れる電流の向きが異なる。このため、第1インダクタ11に流れる電流が一次巻線W1に流れる電流よりも大きい場合の第7状態Φ7を第7-1状態Φ7(1)とし、第1インダクタ11に流れる電流が一次巻線W1に流れる電流よりも小さい場合の第7状態Φ7を第7-2状態Φ7(2)とする。
図8に示すように、第7-1状態Φ7(1)において、電力変換装置1の一次側には電流経路ra6に電流が流れる。
図9に示すように、スイッチングパターンが第6パターンP6であって第1インダクタ11に流れる電流が一次巻線W1に流れる電流よりも小さい第7-2状態Φ7(2)では、電力変換装置1の一次側には電流経路ra7に電流が流れる。
図10に示す第8状態Φ8は、制御部50がスイッチングパターンを第6パターンP6に制御してから所定の時間が経過した状態である。第8状態Φ8は、第1インダクタ11に流れる電流と、一次巻線W1に流れる電流とが一致した状態である。
図11に示す第9状態Φ9は、制御部50がスイッチングパターンを第6パターンP6から第1パターンP1に切り替えた直後の状態である。
本実施形態では、制御部50は、第1インダクタ11を流れる電流と、入力電圧とに基づいて、入力電力の力率が改善するようにスイッチングを制御することが可能である。例えば、制御部50は、第1状態Φ1及び第9状態Φ9の時間を制御することによりブリッジ回路14を力率改善(PFC:Power Factor Correction)回路として動作させる。第1状態Φ1及び第9状態Φ9では、交流電源V1と第1インダクタ11とが閉回路を形成し、交流電源V1からの電流は第1インダクタ11により制限される。第1インダクタ11に流れる電流の増加分は、第1状態Φ1及び第9状態Φ9を継続する時間に比例するため、第1状態Φ1及び第9状態Φ9を継続する時間を制御することにより、第1インダクタ11の電流を制御することが可能となる。制御部50は、第1インダクタ11に流れる電流の波形が略正弦波状になり、当該正弦波の周波数と位相が、交流電源V1の周波数と位相と一致するように、電流センサC1と電圧センサC2からの信号に基づき、第1状態Φ1及び第9状態Φ9の継続時間を制御する。
上記実施形態によれば、以下のような効果を得ることができる。
(1)電力変換装置1は、交流電源V1の極性に応じて、制御部50が各スイッチング素子Q1~Q3のスイッチングを制御することにより、第1状態Φ1~第9状態Φ9に遷移する。これにより、ブリッジ回路14が交流電源V1の交流電圧を直流電圧に変換する。
かかる構成によれば、電力変換装置1は、交流電源V1から供給される電力の力率を改善できる。
○デッドタイムを除くスイッチングパターンは第1パターンP1、第3パターンP3、及び第6パターンP6に限られない。例えば、交流電圧が正極性の場合において、上アームスイッチング素子Q1のみが導通状態となるスイッチングパターンや、交流電圧が負極性の場合において、下アームスイッチング素子Q2のみが導通状態となるスイッチングパターンをデッドタイム以外にも設けてもよい。すなわち、特定パターンとして、両アームスイッチング素子Q1,Q2のいずれか一方が導通状態となり且つ両アームスイッチング素子Q1,Q2の他方及びバッファスイッチング素子Q3が非導通状態となるパターンを採用してもよい。
○制御部50は、コンピュータプログラム(ソフトウェア)に従って各種処理を実行する1つ以上のプロセッサを含む回路(circuitry)として構成し得る。なお、制御部50は、各種処理のうち少なくとも一部の処理を実行する、特定用途向け集積回路(ASIC)等の1つ以上の専用のハードウェア回路を含む回路として構成してもよいし、上記の1つ以上のプロセッサ及び1つ以上の専用のハードウェア回路の組み合わせを含む回路として構成してもよい。プロセッサは、CPU並びに、RAM及びROM等のメモリを含む。メモリ、すなわち非一時的なコンピュータ可読記憶媒体は、処理をCPUに実行させるように構成されたプログラムコード又は指令を格納している。メモリは、汎用又は専用のコンピュータでアクセスできるあらゆる媒体を含む。
(1)制御部は、特定パターンの後、バッファスイッチング素子が導通状態であり且つ両アームスイッチング素子が非導通状態となるデッドタイムパターンを介して、下アームスイッチング素子が非導通状態となり且つ上アームスイッチング素子及びバッファスイッチング素子が導通状態となるスイッチングパターンに切り替えてもよい。
Claims (8)
- 交流電源から入力される交流電圧を直流電圧に変換する電力変換装置であって、
一次巻線と二次巻線とを有するトランスと、
第1キャパシタと、
前記交流電源が接続される一対の入力端と、第1インダクタと、上アームスイッチング素子と、下アームスイッチング素子と、上アーム整流素子と、下アーム整流素子と、を有する一次側回路と、
第2インダクタと、二次側整流素子と、出力キャパシタと、第1出力端及び第2出力端と、を有する整流平滑回路と、
を備え、
前記上アームスイッチング素子と前記下アームスイッチング素子の直列接続と、前記上アーム整流素子と前記下アーム整流素子の直列接続とがブリッジ回路を構成するとともに、前記上アームスイッチング素子と前記下アームスイッチング素子との接続点と、前記上アーム整流素子と前記下アーム整流素子の接続点とが、前記一対の入力端と、前記第1インダクタを介して接続され、
前記一次側回路は、バッファスイッチング素子とバッファキャパシタとを有するバッファ回路を含み、
前記一次側回路は、前記第1キャパシタを介して、前記トランスの前記一次巻線と接続され、
前記整流平滑回路は、前記トランスの前記二次巻線と接続されており、
前記電力変換装置は、前記上アームスイッチング素子、前記下アームスイッチング素子、及び前記バッファスイッチング素子のスイッチングを制御するように構成された制御部を備え、
前記制御部は、前記両アームスイッチング素子のいずれか一方が導通状態になることにより前記交流電源が前記第1インダクタを介して短絡され、且つ前記両アームスイッチング素子の他方が非導通状態となり、且つ前記バッファスイッチング素子が導通状態となるパターンを含むスイッチングパターンを順次切り替えるように、スイッチングを制御する、
電力変換装置。 - 前記バッファ回路は、前記ブリッジ回路に対して並列に接続されている、
請求項1に記載の電力変換装置。 - 前記バッファ回路は、前記トランスの前記一次巻線と並列に接続されている、
請求項1または2に記載の電力変換装置。 - 第2キャパシタを更に有し、
前記整流平滑回路は、
前記第1出力端と前記出力キャパシタの第1端とが接続され、
前記第2出力端と前記出力キャパシタの第2端とが接続され、
前記第2インダクタの第1端が、前記二次側整流素子を介して、前記出力キャパシタの前記第1端に接続され、前記第2インダクタの第2端が、前記出力キャパシタの前記第2端に接続されており、
前記整流平滑回路は、前記第2キャパシタを介して、前記トランスの二次巻線に接続され、
前記一次巻線と前記二次巻線は、前記上アームスイッチング素子と前記下アームスイッチング素子のうち少なくともどちらか一方が非導通状態のときに前記二次側整流素子が導通する極性を有するように磁気結合している、
請求項1から3のうちいずれか一項に記載の電力変換装置。 - 第2キャパシタを更に有し、
前記整流平滑回路は、
前記第1出力端と前記出力キャパシタの第1端とが接続され、
前記第2出力端と前記出力キャパシタの第2端とが接続され、
前記二次側整流素子の第1端が、前記第2インダクタを介して、前記出力キャパシタの前記第1端に接続され、前記二次側整流素子の第2端が、前記出力キャパシタの第2端に接続されており、
前記整流平滑回路は、前記第2キャパシタを介して、前記トランスの二次巻線に接続され、
前記一次巻線と前記二次巻線は、前記上アームスイッチング素子と前記下アームスイッチング素子のうち少なくともどちらか一方が非導通状態のときに前記二次側整流素子が導通する極性を有するように磁気結合している、
請求項1から3のうちいずれか一項に記載の電力変換装置。 - 前記整流平滑回路は、
前記二次側整流素子として、第1二次側整流素子と、第2二次側整流素子とを有し、
前記第1出力端と前記出力キャパシタの第1端とが接続され、
前記第2出力端と前記出力キャパシタの第2端とが接続され、
前記第1二次側整流素子の第1端が、前記第2インダクタを介して、前記出力キャパシタの前記第1端に接続され、
前記第1二次側整流素子の第2端が、前記二次巻線の第1端に接続され、
前記第2二次側整流素子の第1端が、前記第2インダクタと前記第1二次側整流素子との接続点に接続され、
前記第2二次側整流素子の第2端が、前記二次巻線の第2端に接続され、
前記出力キャパシタの前記第2端は、前記二次巻線の中点に接続されており、
前記一次巻線と前記二次巻線は、前記上アームスイッチング素子と前記下アームスイッチング素子のどちらか一方が非導通状態のときに前記第1二次側整流素子、又は前記第2二次側整流素子のいずれか一方が導通する極性を有するように磁気結合している、
請求項1から3のうちいずれか一項に記載の電力変換装置。 - 前記上アーム整流素子、前記下アーム整流素子、及び前記二次側整流素子のうちのいずれか1つまたは全てがスイッチング素子で構成される場合、前記制御部は当該スイッチング素子のスイッチングを制御するものであり、前記交流電圧と、前記第1インダクタを流れる電流とに基づいて、入力電力の力率が改善するようにスイッチングを制御する、
請求項1から6のうちいずれか一項に記載の電力変換装置。 - 前記上アーム整流素子、前記下アーム整流素子、前記二次側整流素子のうちのいずれかまたは全てがスイッチング素子で構成される場合、前記制御部は当該スイッチング素子のスイッチングを制御するものであり、前記第1出力端と前記第2出力端との間の電圧に基づいて、所定の直流電圧が出力されるように、スイッチングを制御する、
請求項1から7のうちいずれか一項に記載の電力変換装置。
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JP2011217566A (ja) * | 2010-04-01 | 2011-10-27 | Minebea Co Ltd | スイッチング電源装置 |
US20130016545A1 (en) * | 2011-07-12 | 2013-01-17 | Fsp-Powerland Technology Inc. | Ac-to-dc conversion apparatus and related control manner thereof |
US20150263605A1 (en) | 2014-03-14 | 2015-09-17 | Delta-Q Technologies Corp. | Hybrid resonant bridgeless ac-dc power factor correction converter |
US20170098993A1 (en) * | 2015-10-06 | 2017-04-06 | Infineon Technologies Austria Ag | Circuitry for power factor correction and methods of operation |
JP2019041428A (ja) | 2015-12-11 | 2019-03-14 | 株式会社日立製作所 | 電源装置およびその初充電制御方法 |
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JP2011217566A (ja) * | 2010-04-01 | 2011-10-27 | Minebea Co Ltd | スイッチング電源装置 |
US20130016545A1 (en) * | 2011-07-12 | 2013-01-17 | Fsp-Powerland Technology Inc. | Ac-to-dc conversion apparatus and related control manner thereof |
US20150263605A1 (en) | 2014-03-14 | 2015-09-17 | Delta-Q Technologies Corp. | Hybrid resonant bridgeless ac-dc power factor correction converter |
US20170098993A1 (en) * | 2015-10-06 | 2017-04-06 | Infineon Technologies Austria Ag | Circuitry for power factor correction and methods of operation |
JP2019041428A (ja) | 2015-12-11 | 2019-03-14 | 株式会社日立製作所 | 電源装置およびその初充電制御方法 |
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