Power conversion device and program

Abstract

To provide a power conversion device and a program, that correspond to both of a three-phase AC power supply and a single phase AC power supply.SOLUTION: A power conversion device 10 comprises: a connection path 44; a single phase charging switch 45 that is provided to the connection path 44; first to third capacitors 161 to 163; a connection switch 151; first and second DC side capacitors 34A and 34B; and a control device 70. The control device 70 performs a switching control of a first upper arm switch S1H and a first lower arm switch S1L in order to perform a power conversion between a first AC terminal Tac1 and a fourth AC terminal Tac4 and between a high-potential side DC terminal TdcH and a low-potential side DC terminal TdcL in a state of turning on the single phase charging switch 45 and turning off the connection switch 151 in the case where it is determined that a single phase AC power supply is connected to the first AC terminal Tac1 and the fourth AC terminal Tac4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power conversion device and a program. [Background technology]

[0002] A power conversion device connectable to a three-phase AC power supply is known, as described in Patent Document 1. This power conversion device includes a series connection of upper and lower arm switches for three phases. The high-potential side terminal of each upper arm switch is electrically connected to a high-potential side DC terminal, and the low-potential side terminal of each lower arm switch is electrically connected to a low-potential side DC terminal.

[0003] The power conversion device further includes first to third inductors, wherein the first inductor electrically connects the connection point of the first upper and lower arm switches to a first AC terminal, the second inductor electrically connects the connection point of the second upper and lower arm switches to a second AC terminal, and the third inductor electrically connects the connection point of the third upper and lower arm switches to a third AC terminal.

[0004] When a three-phase AC power supply is connected to the first AC terminal, the second AC terminal, and the third AC terminal, the power conversion device converts AC power input from the first AC terminal, the second AC terminal, and the third AC terminal into DC power and outputs it from the high-potential side DC terminal and the low-potential side DC terminal, by controlling the switching of each upper and lower arm switch.

[0005] The power conversion device further includes first to third capacitors that are X capacitors. The first terminal of the first capacitor is electrically connected to the first AC terminal, the first terminal of the second capacitor is electrically connected to the second AC terminal, and the first terminal of the third capacitor is electrically connected to the third AC terminal. The second terminals of the first, second, and third capacitors are electrically connected to each other at a neutral point, and the neutral point is connected to a connection point of a pair of series-connected DC side capacitors that electrically connects the high potential side DC terminal and the low potential side DC terminal. This makes it possible to reduce common mode noise when the switching control is performed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6636219 Summary of the Invention [Problem to be solved by the invention]

[0007] There is a demand for power conversion devices that are compatible with single-phase AC power supplies in addition to three-phase AC power supplies.

[0008] A main object of the present invention is to provide a power conversion device and a program that are compatible with both a three-phase AC power supply and a single-phase AC power supply. [Means for solving the problem]

[0009] The present invention provides a power supply comprising a first AC terminal, a second AC terminal, a third AC terminal, and a fourth AC terminal, a high potential side DC terminal and a low potential side DC terminal; Equipped with A power conversion device configured to allow a three-phase AC power supply to be connected to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC power supply to be connected to the first AC terminal and the fourth AC terminal, a series connection of a first upper arm switch and a first lower arm switch; a series connection of a second upper arm switch and a second lower arm switch; a series connection of a third upper arm switch and a third lower arm switch; a series connection of an upper arm rectifier and a lower arm rectifier; a first inductor electrically connecting a connection point between the first upper arm switch and the first lower arm switch and the first AC terminal; a second inductor electrically connecting a connection point between the second upper arm switch and the second lower arm switch and the second AC terminal; a third inductor electrically connecting a connection point between the third upper arm switch and the third lower arm switch and the third AC terminal; a connection path that electrically connects a connection point between the upper arm rectifier and the lower arm rectifier and the fourth AC terminal; a single-phase charging switch provided in the connection path; A first capacitor; A second capacitor; a third capacitor; A connection switch; a DC side connection portion; A control unit; Equipped with high potential side terminals of the first, second, and third upper arm switches and a high potential side terminal of the upper arm rectifier unit are electrically connected to the high potential side DC terminal; low potential side terminals of the first, second, and third lower arm switches and a low potential side terminal of the lower arm rectifier unit are electrically connected to the low potential side DC terminal; the first AC terminal of the first inductor is electrically connected to a first end of the first capacitor; the second AC terminal side of the second inductor is electrically connected to a first end of the second capacitor, the third AC terminal side of the third inductor is electrically connected to a first end of the third capacitor, second ends of the first capacitor, the second capacitor, and the third capacitor are electrically connected to each other; a second end of each of the first capacitor, the second capacitor, and the third capacitor is electrically connected to the DC side connection portion via the connection switch, The DC side connection portion is a connection point between a first DC side capacitor and a second DC side capacitor connected in series, the connection point electrically connecting the high potential side DC terminal and the low potential side DC terminal; the high potential side DC terminal, or the low potential side DC terminal Either When the control unit determines that the single-phase AC power supply is connected to the first AC terminal and the fourth AC terminal, it turns on the single-phase charging switch and turns off the connection switch, and performs switching control of the first upper arm switch and the first lower arm switch to perform power conversion between the first AC terminal and the fourth AC terminal and the high potential side DC terminal and the low potential side DC terminal.

[0010] In the present invention, a single-phase charging switch is provided in a connection path electrically connecting a connection point between the upper arm rectifier and the lower arm rectifier and the fourth AC terminal. When the control unit determines that a single-phase AC power supply is connected to the first AC terminal and the fourth AC terminal, the control unit controls switching of the first upper arm switch and the first lower arm switch with the single-phase charging switch turned on to perform power conversion between the first AC terminal and the fourth AC terminal and the high-potential side DC terminal and the low-potential side DC terminal. In this way, according to the present invention, it is possible to provide a power conversion device that is compatible with both a three-phase AC power supply and a single-phase AC power supply.

[0011] Furthermore, in the present invention, when a single-phase AC power supply is connected and the switching control is performed, the connection switches that electrically connect the second terminals of the first to third capacitors to the DC side connection part are turned off, thereby preventing an overcurrent from flowing through the first to third capacitors due to the switching control. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing the overall configuration of an on-board charger according to a first embodiment; [Figure 2] FIG. 1 shows an on-board charger connected to a three-phase AC power supply. [Figure 3] 1 is a diagram showing an on-board charger connected to a single-phase AC power supply; [Figure 4] 4 is a flowchart showing a procedure for controlling charging of a storage battery. [Figure 5] Block diagram of three-phase charging control processing. [Figure 6] 4 is a time chart showing the changes in current and voltage during three-phase charging control. [Figure 7] 5 is a time chart showing changes in current and voltage during three-phase charging control according to a comparative example. [Figure 8] Block diagram of single-phase charging control processing. [Figure 9] 4 is a time chart showing the transition of current and voltage during single-phase charging control. [Figure 10] 4 is a time chart showing the overcurrent prevention effect of the first embodiment. [Figure 11] 10 is a time chart showing a case where an overcurrent flows according to a comparative example. [Figure 12] FIG. 10 is a diagram showing the overall configuration of an on-board charger according to a second embodiment. [Figure 13] FIG. 10 is a diagram showing the overall configuration of an on-board charger according to a third embodiment. [Figure 14] 4 is a flowchart showing a procedure for controlling charging of a storage battery. [Figure 15] FIG. 10 is a diagram showing the overall configuration of an on-board charger according to a fourth embodiment. [Figure 16] 4 is a flowchart showing a procedure for controlling charging of a storage battery. [Figure 17] 10 is a time chart showing interleaved driving according to another embodiment. [Figure 18] 10 is a time chart showing switching modes and the like in the case where interleaved driving is not performed; [Figure 19] FIG. 10 is a diagram illustrating the overall configuration of an on-board charger according to another embodiment. [Figure 20] FIG. 10 is a diagram illustrating the overall configuration of an on-board charger according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be assigned the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0014] First Embodiment A first embodiment of a power conversion device according to the present invention will be described below with reference to the drawings. The power conversion device according to this embodiment is provided in a vehicle such as an electric vehicle, and specifically, is an AC-DC converter constituting an on-board charger. The on-board charger is also called an on-board charger.

[0015] The power conversion device has an AC terminal and a DC terminal. The power conversion device has a function of converting AC power input via the AC terminal connected to an AC power source external to the vehicle into DC power and outputting it from the DC terminal. The DC power output from the DC terminal is supplied to a storage battery provided in the vehicle. The power conversion device also has a function of converting DC power input via the DC terminal into AC power and outputting it from the AC terminal. The AC power output from the AC terminal is supplied to an external power system via the external AC power source. The power conversion device can be connected to a three-phase AC power source or a single-phase AC power source.

[0016] As shown in Fig. 1, the power conversion device 10 includes a first AC terminal Tac1, a second AC terminal Tac2, a third AC terminal Tac3, and a fourth AC terminal Tac4 as AC terminals. Of the first to fourth AC terminals Tac1 to Tac4, the first to third AC terminals Tac1 to Tac3 are connectable to an external three-phase AC power supply 21, as shown in Fig. 2. Of the first to fourth AC terminals Tac1 to Tac4, the first and fourth AC terminals Tac1 and Tac4 are connectable to an external single-phase AC power supply 22, as shown in Fig. 3.

[0017] The power conversion device 10 has a high-potential side DC terminal TdcH and a low-potential side DC terminal TdcL as DC terminals. The high-potential side DC terminal TdcH and the low-potential side DC terminal TdcL are connected to an input section of a DC-DC converter 24 constituting an on-board charger. The output section of the DC-DC converter 24 is connected to a chargeable and dischargeable storage battery 20 mounted on the vehicle. The DC-DC converter 24 transforms a DC voltage input from the high-potential side DC terminal TdcH and the low-potential side DC terminal TdcL and supplies the transformed DC voltage to the storage battery 20. The DC-DC converter 24 also transforms a DC voltage input from the storage battery 20 and supplies the transformed DC voltage to the high-potential side DC terminal TdcH and the low-potential side DC terminal TdcL. The DC-DC converter 24 is, for example, an isolated DC-DC converter whose input section and output section are electrically insulated from each other and includes a transformer connecting the input section and the output section.

[0018] The power conversion device 10 includes four upper and lower arm switches for four phases: a series connection of a first upper arm switch S1H and a first lower arm switch S1L, a series connection of a second upper arm switch S2H and a second lower arm switch S2L, a series connection of a third upper arm switch S3H and a third lower arm switch S3L, and a series connection of a fourth upper arm switch S4H and a fourth lower arm switch S4L. In this embodiment, each of the upper and lower arm switches S1H to S4L is an N-channel MOSFET having a body diode. Therefore, in each of the upper and lower arm switches S1H to S4L, the high-potential side terminal is the drain and the low-potential side terminal is the source. Of the first to third phases, for example, the first phase is the U-phase, the second phase is the V-phase, and the third phase is the W-phase. The fourth upper arm switch S4H corresponds to the "upper arm rectifier" and the fourth lower arm switch S4L corresponds to the "lower arm rectifier."

[0019] The power conversion device 10 includes a high-potential-side path 30H that is an electrical path connecting high-potential-side terminals of the first, second, third, and fourth upper-arm switches S1H, S2H, S3H, and S4H to a high-potential-side DC terminal TdcH, and a low-potential-side path 30L that is an electrical path connecting low-potential-side terminals of the first, second, third, and fourth lower-arm switches S1L, S2L, S3L, and S4L to a low-potential-side DC terminal TdcL. The high-potential-side path 30H and the low-potential-side path 30L are conductive members such as bus bars.

[0020] The power conversion device 10 includes a series connection of a first DC side capacitor 34A and a second DC side capacitor 34B. This series connection connects a high potential side path 30H and a low potential side path 30L. In this embodiment, the first DC side capacitor 34A and the second DC side capacitor 34B correspond to the "DC side connection part."

[0021] The power conversion device 10 includes a first path 41, a second path 42, and a third path 43. The first path 41 is an electrical path connecting the low potential side terminal of the first upper arm switch S1H and the high potential side terminal of the first lower arm switch S1L with the first AC terminal Tac1. The second path 42 is an electrical path connecting the low potential side terminal of the second upper arm switch S2H and the high potential side terminal of the second lower arm switch S2L with the second AC terminal Tac2. The third path 43 is an electrical path connecting the low potential side terminal of the third upper arm switch S3H and the high potential side terminal of the third lower arm switch S3L with the third AC terminal Tac3.

[0022] The power conversion device 10 includes a first inductor 31 provided in a first path 41, a second inductor 32 provided in a second path 42, and a third inductor 33 provided in a third path 43. In this embodiment, the inductors 31 to 33 have the same specifications. Therefore, the inductors 31 to 33 have the same inductance value. Furthermore, the inductors 31 to 33 have the same rated current (specifically, temperature rise rated current).

[0023] The power conversion device 10 includes an AC-side filter 35. The AC-side filter 35 is provided on each of the paths 41 to 43 closer to each of the AC terminals Tac1 to Tac3 than the inductors 31 to 33. The AC-side filter 35 is provided to reduce, for example, common mode noise.

[0024] The power conversion device 10 includes a connection path 44, which is an electrical path connecting the low potential side terminal of the fourth upper arm switch S4H and the high potential side terminal of the fourth lower arm switch S4L with the fourth AC terminal Tac4. The power conversion device 10 also includes a single-phase charging switch 45 provided in the connection path 44. The single-phase charging switch 45 allows bidirectional current flow when turned on and blocks bidirectional current flow when turned off.

[0025] The power conversion device 10 includes a first capacitor 161, a second capacitor 162, a third capacitor 163, and a connection switch 151 as X capacitors. A first end of the first capacitor 161 is connected to a portion of the first path 41 between the first inductor 31 and the AC-side filter 35. A first end of the second capacitor 162 is connected to a portion of the second path 42 between the second inductor 32 and the AC-side filter 35. A first end of the third capacitor 163 is connected to a portion of the third path 43 between the third inductor 33 and the AC-side filter 35. Second ends of the first capacitor 161, the second capacitor 162, and the third capacitor 163 are connected to each other at a neutral point. The neutral points of the capacitors 161 to 163 are connected to a connection point between the first DC-side capacitor 34A and the second DC-side capacitor 34B via the connection switch 151. The connection switch 151 allows bidirectional current flow when turned on and blocks bidirectional current flow when turned off.

[0026] The power conversion device 10 includes a DC-side voltage sensor 50 and an AC-side voltage sensor 51. The DC-side voltage sensor 50 detects the terminal voltage of the series-connected body of the first and second DC-side capacitors 34A and 34B, and the AC-side voltage sensor 51 detects the voltage difference between the first AC terminal Tac1 and the fourth AC terminal Tac4.

[0027] The power conversion device 10 includes first to third current sensors 61 to 63. The first current sensor 61 detects the current flowing through the first inductor 31, the second current sensor 62 detects the current flowing through the second inductor 32, and the third current sensor 63 detects the current flowing through the third inductor 33. The detected values ​​of the sensors 50, 51, 61 to 63 are input to a control device 70 serving as a control unit included in the power conversion device 10.

[0028] The control device 70 is mainly composed of a microcomputer 71, which includes a CPU. The functions provided by the microcomputer 71 can be provided by software stored in a physical memory device and a computer executing the software, by software alone, by hardware alone, or a combination thereof. For example, if the microcomputer 71 is provided by a hardware electronic circuit, the function can be provided by a digital circuit including multiple logic circuits or an analog circuit. For example, the microcomputer 71 executes a program stored in a non-transitory tangible storage medium serving as a storage unit of the microcomputer 71. The program includes, for example, programs for the processes shown in Figures 4, 5, and 8 (described below). Execution of the program results in the execution of a method corresponding to the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, via OTA (Over The Air) or other means.

[0029] The control device 70 performs three-phase charging control or single-phase charging control. The charging control will be described below with reference to the flowchart of FIG.

[0030] In step S10, it is determined whether a command for three-phase charging control has been issued. In this embodiment, as shown in Fig. 2, if it is determined that a three-phase AC power supply 21 is connected to the first to third AC terminals Tac1 to Tac3, it is determined that a command for three-phase charging control has been issued. In the three-phase AC power supply 21, the amplitude and frequency of the output voltages of the three phases are the same, and the phases of the output voltages and output currents are shifted by 120° for each phase. Note that, although the neutral point of the three-phase AC power supply 21 is connected to the fourth AC terminal Tac4 in Fig. 2, the neutral point does not have to be connected to the fourth AC terminal Tac4.

[0031] If the determination in step S10 is affirmative, three-phase charging control is performed in steps S11 and S12. Specifically, in step S11, the single-phase charging switch 45, the fourth upper arm switch S4H, and the fourth lower arm switch S4L are turned off, and the connection switch 151 is turned on.

[0032] In step S12, the first, second, and third upper-arm switches S1H, S2H, and S3H and the first, second, and third lower-arm switches S1L, S2L, and S3L are switched on alternately with dead times between them, so that AC power input from the first AC terminal Tac1, the second AC terminal Tac2, and the third AC terminal Tac3 is converted into DC power and output from the high-potential side DC terminal TdcH and the low-potential side DC terminal TdcL. In each phase, the upper and lower arm switches are alternately turned on with dead times between them. In each phase, the upper and lower arm switches have the same switching period.

[0033] By turning on the connection switch 151, the voltages to ground, which are the voltages of the DC terminals TdcH and TdcL relative to the voltage of the neutral point (hereinafter referred to as the ground voltage) of the three-phase AC power supply 21, are stabilized. As a result, common mode noise caused by stray capacitance between the high potential side path 30H and the low potential side path 30L and the ground, and the like, can be reduced.

[0034] If the determination in step S10 is negative, the process proceeds to step S13, where it is determined whether or not a command for single-phase charging control has been issued. In this embodiment, as shown in FIG. 3 , if it is determined that the single-phase AC power supply 22 is connected to the first AC terminal Tac1 and the fourth AC terminal Tac4, it is determined that a command for single-phase charging control has been issued. In this embodiment, the amplitude of the output voltage of the single-phase AC power supply 22 is the same as the amplitude of the output voltage of the three-phase AC power supply 21. In addition, the frequency of the output voltage of the single-phase AC power supply 22 is the same as the frequency of the output voltage of the three-phase AC power supply 21.

[0035] If the determination in step S13 is affirmative, single-phase charging control is performed in steps S14 and S15. Specifically, in step S14, the single-phase charging switch 45 is turned on, and the connection switch 151 is turned off.

[0036] In step S15, the first upper arm switch S1H and the first lower arm switch S1L are switched on and off to convert the AC power input from the first AC terminal Tac1 and the fourth AC terminal Tac4 into DC power and output it from the high potential side DC terminal TdcH and the low potential side DC terminal TdcL. The first upper arm switch S1H and the first lower arm switch S1L are alternately turned on in synchronization with each other with dead time therebetween. The first upper and lower arm switches S1H and S1L have the same switching cycle, which is the same as that during three-phase charging control. The connection switch 151 is turned off to prevent overcurrent from flowing through the first to third capacitors 161 to 163.

[0037] In step S15, the fourth lower arm switch S4L is turned on and the fourth upper arm switch S4H is turned off during a first period in which an AC current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 22. On the other hand, during a second period in which a current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 22, the fourth upper arm switch S4H is turned on and the fourth lower arm switch S4L is turned off. Whether the current timing falls within the first period or the second period may be determined based on, for example, a detection value of the first current sensor 61.

[0038] Note that one switching period of the fourth upper and lower arm switches S4H, S4L is the same as one period of the output voltage of the single-phase AC power supply 22 and is longer than one switching period of the first upper and lower arm switches S1H, S1L. This is because, for the first phase, high-frequency switching (e.g., tens of kHz to hundreds of kHz) is required to reduce ripple in the current flowing through the first inductor 31, while for the fourth phase, switching at a frequency equivalent to the fundamental frequency (e.g., 50 Hz or 60 Hz) of the output voltage of the single-phase AC power supply 22 is sufficient. For this reason, in this embodiment, the fourth upper and lower arm switches S4H, S4L are semiconductor switching elements with longer turn-on and turn-off times than the first upper and lower arm switches S1H, S1L. This eliminates the need for high-performance switches as the fourth upper and lower arm switches S4H, S4L, thereby reducing the cost of the power conversion device 10.

[0039] During single-phase charging control, when DC power input from each DC terminal TdcH, TdcL is converted into AC power and output from AC terminals Tac1, Tac4 by switching control of the first upper and lower arm switches S1H, S1L, in step S15, the fourth upper arm switch S4H is turned on and the fourth lower arm switch S4L is turned off during a first period when current is flowing from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 22. On the other hand, during a second period when current is flowing from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 22, the fourth lower arm switch S4L is turned on and the fourth upper arm switch S4H is turned off.

[0040] Next, the three-phase charging control will be described with reference to Fig. 5. Fig. 5 is a block diagram of the three-phase charging control executed by the control device 70.

[0041] The voltage control unit 80 calculates a d-axis target current Idref for controlling the terminal voltage detected by the DC side voltage sensor 50 (hereinafter referred to as the DC voltage detection value Vdcr) to the target DC voltage Vdcref. More specifically, the voltage control unit 80 includes a voltage deviation calculation unit 81 and a voltage feedback control unit 82. The voltage deviation calculation unit 81 calculates a voltage deviation ΔV by subtracting the DC voltage detection value Vdcr from the target DC voltage Vdcref. The target DC voltage Vdcref may be set based on the rated voltages of the upper and lower arm switches S1H to S4L and the DC-DC converter 24, for example.

[0042] The voltage feedback control unit 82 calculates the d-axis target current Idref as a manipulated variable for feedback controlling the voltage deviation ΔV to 0. The feedback control in the voltage feedback control unit 82 is, for example, proportional-integral control.

[0043] The electrical angle calculation unit 83 calculates the electrical angle θe based on the voltage detected by the AC-side voltage sensor 51 (hereinafter referred to as the detected AC voltage value V1r). In this embodiment, the electrical angle θe at the zero-cross timing (specifically, for example, the zero-upcross timing) of the detected AC voltage value V1r is set to 0°, and the electrical angle θe at the next zero-upcross timing is set to 360°. As a result, one cycle of the detected AC voltage value V1r corresponds to one electrical angle cycle (0° to 360°). In this embodiment, the detected AC voltage value V1r is set to positive when the voltage at the first AC terminal Tac1 is higher than the voltage at the fourth AC terminal Tac4.

[0044] The two-phase conversion unit 84 converts the first, second, and third current detection values ​​i1r, i2r, and i3r in the three-phase fixed coordinate system into d- and q-axis currents Idr and Iqr in the two-phase rotating coordinate system (dq-axis coordinate system) based on the currents detected by the first, second, and third current sensors 61, 62, and 63 (hereinafter referred to as first, second, and third current detection values ​​i1r, i2r, and i3r) and the electrical angle θe. In this embodiment, the first, second, and third current detection values ​​i1r, i2r, and i3r are defined as positive when they flow from the first, second, and third AC terminals Tac1, Tac2, and Tac3 toward the first, second, and third inductors 31, 32, and 33.

[0045] The current control unit 85 includes a d-axis deviation calculation unit 86 , a d-axis feedback control unit 87 , a q-axis deviation calculation unit 88 , and a q-axis feedback control unit 89 .

[0046] A d-axis deviation calculation unit 86 calculates a d-axis current deviation ΔId by subtracting the d-axis current Idr from the d-axis target current Idref. A d-axis feedback control unit 87 calculates a d-axis target voltage Vdref as a manipulated variable for feedback controlling the d-axis current deviation ΔId to zero. The feedback control in the d-axis feedback control unit 87 is, for example, proportional-integral control.

[0047] The q-axis deviation calculation unit 88 calculates the q-axis current deviation ΔIq by subtracting the q-axis current Iqr from the q-axis target current Iqref. The q-axis target current Iqref is a target value of the reactive current, and in this embodiment, is set to 0 to make the power factor 1. Making the power factor 1 means making the phase difference between the first, second, and third output voltages V1, V2, and V3 of the three-phase AC power supply 21 and the first, second, and third detected current values ​​i1r, i2r, and i3r zero. The q-axis feedback control unit 89 calculates the q-axis target voltage Vqref as a manipulated variable for feedback-controlling the q-axis current deviation ΔIq to zero. The feedback control in the q-axis feedback control unit 89 is, for example, proportional-integral control.

[0048] The three-phase conversion unit 90 converts the d- and q-axis target voltages Vdref, Vqref in the two-phase rotating coordinate system into first, second, and third target voltages Vleg1ref, Vleg2ref, and Vleg3ref in the three-phase fixed coordinate system based on the d- and q-axis target voltages Vdref, Vqref and the electrical angle θe. The first, second, and third target voltages Vleg1ref, Vleg2ref, and Vleg3ref are sinusoidal signals whose phases are shifted by 120° in electrical angle increments. The sinusoidal signals become 0 every 180° of electrical angle.

[0049] The PWM generating unit 91 generates first upper and lower arm drive signals to be supplied to the gates of the first upper and lower arm switches S1H and S1L, second upper and lower arm drive signals to be supplied to the gates of the second upper and lower arm switches S2H and S2L, and third upper and lower arm drive signals to be supplied to the gates of the third upper and lower arm switches S3H and S3L by pulse width modulation (PWM) based on a magnitude comparison between the first, second, and third target voltages Vleg1ref, Vleg2ref, and Vleg3ref and a carrier signal. The carrier signal is, for example, a triangular wave signal, and one cycle of the carrier signal is sufficiently shorter than one electrical angle cycle (0° to 360°). Within one electrical angle cycle, the switching patterns of the first upper and lower arm switches S1H and S1L, the second upper and lower arm switches S2H and S2L, and the third upper and lower arm switches S3H and S3L are shifted in phase by 120°.

[0050] 6 shows the transitions of the first, second, and third output voltages V1, V2, and V3 of the three-phase AC power supply 21, the first, second, and third detected current values ​​i1r, i2r, and i3r, the high-side voltage to ground Vdcp, and the low-side voltage to ground Vdcn during three-phase charging control. The first, second, and third output voltages V1, V2, and V3 are positive when the voltages at the first, second, and third AC terminals Tac1, Tac2, and Tac3 are higher than the voltage at the neutral point of the three-phase AC power supply 21. The high-side voltage to ground Vdcp is the difference in voltage between the high-side DC terminal TdcH and the ground voltage, and the low-side voltage to ground Vdcn is the difference in voltage between the low-side DC terminal TdcL and the ground voltage.

[0051] In the example shown in FIG. 6, the frequency of the output voltages V1 to V3 of the three-phase AC power supply 21 is 50 Hz, and the target DC voltage Vdcref is set to 800 V.

[0052] As shown in FIG. 6, three-phase charging control is executed so that the phase difference between the first, second, and third output voltages V1, V2, and V3 and the first, second, and third current detection values ​​i1r, i2r, and i3r is 0 (i.e., the power factor is 1).

[0053] During three-phase charging control, the high-side voltage to ground Vdcp and the low-side voltage to ground Vdcn do not oscillate with the high-frequency switching frequency components of the first upper and lower arm switches S1H and S1L. This is because the connection points on the second ends of the first to third capacitors 161 to 163, which are X capacitors, function as virtual neutral points. This reduces common-mode noise caused by stray capacitance between the high-side path 30H and the low-side path 30L and the ground, and ultimately enables the AC-side filter 35 to be made smaller.

[0054] 7 shows, as a comparative example, a case where the connection switch 151 is turned off during three-phase charging control. In this case, the connection points on the second ends of the first to third capacitors 161 to 163 are electrically disconnected from the connection points of the DC-side capacitors 34A, 34B. As a result, the high-potential-side voltage to ground Vdcp and the low-potential-side voltage to ground Vdcn oscillate with the high-frequency switching frequency components of the first upper and lower arm switches S1H and S1L, and as a result, the AC-side filter 35 needs to be increased in size.

[0055] Incidentally, the control device 70 may perform switching control of the first upper and lower arm switches S1H and S1L based on average current mode control or the like as the three-phase charging control, instead of the control shown in FIG.

[0056] Next, the single-phase charging control will be described with reference to Fig. 8. Fig. 8 is a block diagram of the single-phase charging control executed by the control device 70.

[0057] In the control device 70, the filter unit 112 performs low-pass filtering on the DC voltage detection value Vdcr, thereby removing harmonic components of the output voltage of the single-phase AC power supply 22 that are included in the DC voltage detection value Vdcr. The harmonic components are, for example, components of the secondary frequency of the output voltage (for example, 100 Hz or 120 Hz).

[0058] The voltage control unit 101 includes a voltage deviation calculation unit 102 and a voltage feedback control unit 103. The voltage deviation calculation unit 102 calculates a voltage deviation ΔV by subtracting the DC voltage detection value Vdcr from the target DC voltage Vdcref, from which harmonic components have been removed by the filter unit 112. The voltage feedback control unit 103 calculates a target current amplitude Iampref as a manipulated variable for feedback control to adjust the voltage deviation ΔV to zero. The feedback control in the voltage feedback control unit 103 is, for example, proportional-integral control.

[0059] The electrical angle calculation unit 83 calculates the electrical angle θe based on the AC voltage detection value V1r. The sine wave generation unit 109 generates a sine wave signal "sin×θe" based on the electrical angle θe.

[0060] The current control unit 105 includes a target current calculation unit 106, a current deviation calculation unit 107, and a current feedback control unit .

[0061] The target current calculation unit 106 calculates the target current Iacref by multiplying the target current amplitude Iampref by the sine wave signal "sin×θe." The target current Iacref fluctuates with the same period as the AC voltage detection value V1r.

[0062] The current deviation calculation unit 107 calculates the current deviation ΔI by subtracting the sum of the first current detection value i1r and the second current detection value i2r from the target current Iacref. The sum of the first current detection value i1r and the second current detection value i2r is calculated by the current adder 110.

[0063] The current feedback control unit 108 calculates the first target voltage Vleg1ref as a manipulated variable for feedback controlling the current deviation ΔI to 0. The feedback control in the current feedback control unit 108 is, for example, proportional-integral control.

[0064] The PWM generating unit 111 generates first upper and lower arm drive signals to be supplied to the gates of the first upper and lower arm switches S1H, S1L by pulse width modulation based on a magnitude comparison between the first target voltage Vleg1ref and the carrier signal.

[0065] 9 shows the transitions of the output voltage Vac, output current iac, high-potential-side voltage to ground Vdcp, and low-potential-side voltage to ground Vdcn of the single-phase AC power supply 22 during single-phase charging control. The output voltage Vac of the single-phase AC power supply 22 is considered positive when the voltage on the first AC terminal Tac1 side is higher than the voltage on the fourth AC terminal Tac4 side. The output current iac of the single-phase AC power supply 22 is considered positive when it flows from the fourth AC terminal Tac4 side toward the first AC terminal Tac1 side.

[0066] In the example shown in FIG. 9, the frequency of the output voltage Vac of the single-phase AC power supply 22 is 50 Hz, the effective value of the output voltage Vac is 230 Vrms, and the target DC voltage Vdcref is set to 800 V.

[0067] Single-phase charging control is performed by high-frequency switching control of the first upper and lower arm switches S1H, S1L and 50 Hz switching control of the fourth upper and lower arm switches S4H, S4L, such that the phase difference between the output voltage Vac and the output current iac of the single-phase AC power supply 22 becomes 0 (i.e., the power factor becomes 1).

[0068] 10 shows changes in the output voltage Vac of the single-phase AC power supply 22, the high-potential side voltage to ground Vdcp, the low-potential side voltage to ground Vdcn, the switching state of the first upper arm switch S1H, the terminal voltage Vcx1 of the first capacitor 161, and the current icx1 flowing through the first capacitor 161 during single-phase charging control according to this embodiment. In this embodiment, since the connection switch 151 is turned off during single-phase charging control, no overcurrent flows through the first capacitor 161 due to the switching control of the first upper and lower arm switches S1H and S1L.

[0069] Fig. 11 shows a time chart corresponding to Fig. 10 during single-phase charging control according to a comparative example. In the comparative example, connection switch 151 remains on during single-phase charging control.

[0070] In the comparative example, every time the switching states of the fourth upper and lower arm switches S4H and S4L change, the terminal voltage of the first capacitor 161 changes suddenly, and this sudden change causes a resonant current to flow in the first capacitor 161, resulting in an overcurrent flowing in the first capacitor 161. In the example shown in FIG. 11 , the current flowing in the first capacitor 161 exceeds the allowable upper limit current Ilim of the first capacitor 161.

[0071] As described above, according to this embodiment, the first to third capacitors 161 to 163 can reduce common mode noise during three-phase charging control, while preventing overcurrent from flowing through the first to third capacitors 161 to 163 during single-phase charging control.

[0072] Second Embodiment The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, as shown in Fig. 12, the neutral points of the capacitors 161-163 are connected to one end of the connection switch 151 as well as to a portion of the connection path 44 that is closer to the DC side capacitors 34A, 34B than the single-phase charging switch 45. This is to allow the first to third capacitors 161-163 to function as X capacitors even during single-phase charging control, thereby reducing fluctuations in the high potential side voltage to ground Vdcp and the low potential side voltage to ground Vdcn.

[0073] The three-phase charging control and single-phase charging control in this embodiment are the same as those in the first embodiment shown in Figures 4, 5, and 8. During single-phase charging control, the first path 41 is electrically connected to the connection points of the fourth upper and lower arm switches S4H and S4L by the first capacitor 161. This provides a filtering effect that reduces normal mode noise and common mode noise.

[0074] On the other hand, during three-phase charging control, the fourth upper and lower arm switches S4H and S4L are maintained off, so even if the first capacitor 161 electrically connects the first path 41 to the connection point of the fourth upper and lower arm switches S4H and S4L, there is no adverse effect on the filter performance provided by the first to third capacitors 161 to 163.

[0075] According to the present embodiment described above, the X capacitor can be shared during both three-phase charging control and single-phase charging control. Therefore, there is no need to provide a dedicated X capacitor for single-phase charging control, and the power conversion device 10 can be made smaller.

[0076] Third Embodiment The third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in FIG. 13 , the power conversion device 10 includes a second single-phase charging switch 46. The second single-phase charging switch 46 connects a portion of the first path 41 closer to the first AC terminal Tac1 than the first inductor 31 to a portion of the second path 42 closer to the second AC terminal Tac2 than the second inductor 32. The second single-phase charging switch 46 allows bidirectional current flow when turned on and blocks bidirectional current flow when turned off. The second single-phase charging switch 46 may, for example, connect the first AC terminal Tac1 and the second AC terminal Tac2. In this embodiment, the single-phase charging switch 45 will be referred to as the first single-phase charging switch 45.

[0077] The three-phase charging control or single-phase charging control executed by the control device 70 will be described with reference to FIG.

[0078] In step S20, similar to step S10, it is determined whether or not a command for three-phase charging control has been issued.

[0079] If the determination in step S20 is affirmative, three-phase charging control is performed in steps S21 and S22. Specifically, in step S21, the first single-phase charging switch 45, the second single-phase charging switch 46, the fourth upper arm switch S4H, and the fourth lower arm switch S4L are turned off, and the connection switch 151 is turned on.

[0080] In step S22, similar to step S12, switching control is performed on the first, second, and third upper arm switches S1H, S2H, and S3H and the first, second, and third lower arm switches S1L, S2L, and S3L to convert the AC power input from the first AC terminal Tac1, the second AC terminal Tac2, and the third AC terminal Tac3 into DC power and output it from the high potential side DC terminal TdcH and the low potential side DC terminal TdcL.

[0081] If the determination in step S20 is negative, the process proceeds to step S23. In step S23, similar to step S13, it is determined whether or not a command for single-phase charging control has been issued.

[0082] If the determination in step S23 is affirmative, single-phase charging control is performed in steps S24 and S25. Specifically, in step S24, the first single-phase charging switch 45 and the second single-phase charging switch 46 are turned on, and the connection switch 151 is turned off.

[0083] In step S25, the first upper arm switch S1H, the first lower arm switch S1L, the second upper arm switch S2H, and the second lower arm switch S2L are switched on in order to convert the AC power input from the first AC terminal Tac1 and the fourth AC terminal Tac4 into DC power and output it from the high potential side DC terminal TdcH and the low potential side DC terminal TdcL. In each phase, the upper arm switches and the lower arm switches are alternately turned on in synchronization with each other with dead time therebetween. In each phase, one switching cycle of the upper and lower arm switches is the same, which is the same as one switching cycle during three-phase charging control.

[0084] In step S25, the fourth lower arm switch S4L is turned on and the fourth upper arm switch S4H is turned off during a first period in which an AC current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 22. On the other hand, during a second period in which a current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 22, the fourth upper arm switch S4H is turned on and the fourth lower arm switch S4L is turned off.

[0085] According to the present embodiment described above, the second single-phase charging switch 46 is turned on during single-phase charging control, and the first and second inductors 31 and 32 can be used as a power transmission path, thereby increasing the DC power output from the high potential side DC terminal TdcH and the low potential side DC terminal TdcL.

[0086] Furthermore, according to this embodiment, the second capacitor 162 can also exhibit filtering performance during single-phase charging control, thereby improving the effect of reducing common-mode noise.

[0087] <Fourth embodiment> The fourth embodiment will be described below with reference to the drawings, focusing on differences from the third embodiment. In this embodiment, as shown in FIG. 15 , the power conversion device 10 includes a series connection of a compensation capacitor 47 and a compensation switch 48 as a configuration for reducing pulsation in the DC power output from each of the DC terminals TdcH and TdcL. The series connection of the compensation capacitor 47 and the compensation switch 48 connects the high-potential-side path 30H to a portion of the third path 43 closer to the third AC terminal Tac3 than the third inductor 33. The compensation capacitor 47 is, for example, a film capacitor. The compensation switch 48 allows bidirectional current flow when turned on and blocks bidirectional current flow when turned off. The series connection of the compensation capacitor 47 and the compensation switch 48 may connect the high-potential-side path 30H to the third AC terminal Tac3. Alternatively, the compensation capacitor 47 may be located closer to the high-potential-side path 30H than the compensation switch 48.

[0088] The power conversion device 10 includes a compensation voltage sensor 52. The compensation voltage sensor 52 detects the terminal voltage of the compensation capacitor 47. The detected value of the compensation capacitor 47 is input to the control device .

[0089] The three-phase charging control or single-phase charging control executed by the control device 70 will be described with reference to FIG.

[0090] In step S30, similar to step S20, it is determined whether or not a command for three-phase charging control has been issued.

[0091] If the determination in step S30 is affirmative, three-phase charging control is performed in steps S31 and S32. Specifically, in step S31, the first single-phase charging switch 45, the second single-phase charging switch 46, the compensation switch 48, the fourth upper arm switch S4H, and the fourth lower arm switch S4L are turned off, and the connection switch 151 is turned on.

[0092] In step S32, similar to step S22, switching control is performed on the first, second, and third upper arm switches S1H, S2H, and S3H and the first, second, and third lower arm switches S1L, S2L, and S3L to convert the AC power input from the first AC terminal Tac1, the second AC terminal Tac2, and the third AC terminal Tac3 into DC power and output it from the high potential side DC terminal TdcH and the low potential side DC terminal TdcL.

[0093] If the determination in step S30 is negative, the process proceeds to step S33, where it is determined whether or not a command for single-phase charging control has been issued, similar to step S23.

[0094] If the determination in step S33 is affirmative, single-phase charging control is performed in steps S34 and S35. Specifically, in step S34, the first single-phase charging switch 45, the second single-phase charging switch 46, and the compensation switch 48 are turned on. Also, the connection switch 151 is turned off.

[0095] In step S35, the first upper arm switch S1H, the first lower arm switch S1L, the second upper arm switch S2H, and the second lower arm switch S2L are switched on in order to convert the AC power input from the first AC terminal Tac1 and the fourth AC terminal Tac4 into DC power and output it from the high potential side DC terminal TdcH and the low potential side DC terminal TdcL. In each phase, the upper arm switches and the lower arm switches are alternately turned on in synchronization with each other with dead time therebetween. In each phase, one switching cycle of the upper and lower arm switches is the same, which is the same as one switching cycle during three-phase charging control.

[0096] Furthermore, in order to reduce pulsation in the DC power output from the high potential side DC terminal TdcH and the low potential side DC terminal TdcL due to charging and discharging of the compensation capacitor 47, switching control of the third upper arm switch S3H and the third lower arm switch S3L is performed based on the detection value of the compensation voltage sensor 52. The third upper arm switch S3H and the third lower arm switch S3L are alternately turned on with dead time therebetween. The third upper and lower arm switches S3H and S3L have the same switching period, which is also the same as the first and second upper and lower arm switches S1H, S1L, S2H, and S2L.

[0097] Also, in step S35, similar to step S25, the fourth lower arm switch S4L is turned on and the fourth upper arm switch S4H is turned off during a first period in which an AC current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 22. On the other hand, during a second period in which a current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 22, the fourth upper arm switch S4H is turned on and the fourth lower arm switch S4L is turned off.

[0098] According to the present embodiment described above in detail, during single-phase charging control, it is possible to reduce pulsation in the DC power while increasing the DC power output from the power conversion device 10. This allows the capacitance of each of the DC-side capacitors 34A, 34B to be reduced, and the size of each of the DC-side capacitors 34A, 34B to be reduced.

[0099] <Other embodiments> The above-described embodiments may be modified as follows.

[0100] The configurations described in the third and fourth embodiments may be applied to the second embodiment.

[0101] In the configuration of the fourth embodiment shown in FIG. 15, instead of the high-potential side path 30H, the low-potential side path 30L may be connected to the third path 43 via a series connection of a compensation capacitor 47 and a compensation switch 48.

[0102] In the fourth embodiment, instead of the compensation capacitor 47, for example, a small-capacity rechargeable battery may be provided.

[0103] In the third and fourth embodiments, the control device 70 may perform interleaved driving of the first and second upper and lower arm switches S1H, S1L, S2H, and S2L during single-phase charging control, as shown in FIG. 17. Interleaved driving is switching control in which the timing at which the first upper arm switch S1H is turned on and the timing at which the second upper arm switch S2H is turned on are shifted by 180 electrical degrees. FIG. 17 also shows the transitions of the first and second current detection values ​​i1r and i2r and the currents flowing through the DC-side capacitors 34A and 34B in the case of interleaved driving. FIG. 18 shows switching control without interleaved driving as a comparative example. Tsw1 and Tsw2 in FIGS. 17 and 18 indicate one switching period of the first and second upper arm switches S1H and S2H.

[0104] When interleaved driving is performed, the current flowing through the first inductor 31 and the current flowing through the second inductor 32 flow in such a way that the current ripples cancel each other out. This reduces the current ripple components that flow in and out of the DC-side capacitors 34A, 34B and that fluctuate with the switching frequencies of the first and second upper and lower arm switches S1H, S1L, S2H, and S2L. As a result, the rated value of the ripple current of each DC-side capacitor 34A, 34B can be reduced, which in turn reduces the capacitance of each DC-side capacitor 34A, 34B and allows the DC-side capacitors 34A, 34B to be made smaller.

[0105] During single-phase charging control, if bidirectional power conversion is not performed and only unidirectional power conversion from AC power to DC power is performed, upper and lower arm diodes D4H and D4L may be provided instead of the fourth upper and lower arm switches S4H and S4L, as shown in Fig. 19. In this case, the cathodes of the diodes D4H and D4L correspond to the high-potential side terminals, and the anodes correspond to the low-potential side terminals.

[0106] 20, the power conversion device 10 may include a DC side capacitor 34 instead of the series connection of the first and second DC side capacitors 34A, 34B. In this case, the connection switch 151 may connect the connection point on the second end side of the first to third capacitors 161 to 163 to the high potential side path 30H. In this case, the connection switch 151 electrically connects the connection point on the second end side of the first to third capacitors 161 to 163 to the high potential side DC terminal TdcH (corresponding to the "DC side connection part").

[0107] The connection switch 151 may also connect the connection points on the second end sides of the first to third capacitors 161 to 163 to the low potential side path 30L. In this case, the connection switch 151 electrically connects the connection points on the second end sides of the first to third capacitors 161 to 163 to the low potential side DC terminal TdcL (corresponding to the "DC side connection part").

[0108] The power conversion device 10 may have only the second function of converting AC power input via AC terminals connected to an external AC power source into DC power and outputting the DC power from the DC terminals, and the first function of converting DC power input via the DC terminals into AC power and outputting the AC power from the AC terminals.

[0109] The AC side filter 35 does not have to be provided.

[0110] The first upper arm switch may be configured as a parallel connection of a plurality of N-channel MOSFETs. The same applies to the first lower arm switch and the second to fourth upper and lower arm switches.

[0111] The upper and lower arm switches are not limited to N-channel MOSFETs, but may be, for example, IGBTs with freewheeling diodes connected in reverse parallel. In this case, the collector of the IGBT corresponds to the high-potential terminal, and the emitter corresponds to the low-potential terminal.

[0112] Instead of the first and second DC side capacitors 34A, 34B and the DC side capacitor 34, for example, a small-capacity chargeable and dischargeable storage battery may be provided.

[0113] The power storage unit connected to the output of the DC-DC converter 24 is not limited to a storage battery, but may be, for example, a large-capacity electric double layer capacitor, or both a storage battery and an electric double layer capacitor.

[0114] The mobile body on which the power conversion device is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship.Furthermore, the power conversion device is not limited to a mobile body, but may be a stationary device.

[0115] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. [Explanation of symbols]

[0116] 10...power conversion device, 21...three-phase AC power supply, 22...single-phase AC power supply, 31-33...first to third inductors, 44...connection path, 45...single-phase charging switch, 70...control device, 151...connection switch, 161-163...first to third capacitors, S1H, S2H, S3H, S4H...first to fourth upper arm switches, S1L, S2L, S3L, S4L...first to fourth lower arm switches.

Claims

1. a first AC terminal (Tac1), a second AC terminal (Tac2), a third AC terminal (Tac3), and a fourth AC terminal (Tac4); a high potential side DC terminal (TdcH) and a low potential side DC terminal (TdcL); Equipped with A power conversion device (10) configured so that a three-phase AC power supply (21) can be connected to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC power supply (22) can be connected to the first AC terminal and the fourth AC terminal, a series connection of a first upper arm switch (S1H) and a first lower arm switch (S1L); a series connection of a second upper arm switch (S2H) and a second lower arm switch (S2L); a series connection of a third upper arm switch (S3H) and a third lower arm switch (S3L); a series connection of an upper arm rectifier unit (S4H, D4H) and a lower arm rectifier unit (S4L, D4L); a first inductor (31) electrically connecting a connection point between the first upper arm switch and the first lower arm switch and the first AC terminal; a second inductor (32) electrically connecting a connection point between the second upper arm switch and the second lower arm switch and the second AC terminal; a third inductor (33) electrically connecting a connection point between the third upper arm switch and the third lower arm switch and the third AC terminal; a connection path (44) electrically connecting a connection point between the upper arm rectifier and the lower arm rectifier and the fourth AC terminal; a single-phase charging switch (45) provided in the connection path; a first capacitor (161); a second capacitor (162); a third capacitor (163); A connection switch (151), DC side connection portions (34A, 34B, 34); A control unit (70); Equipped with high potential side terminals of the first, second and third upper arm switches and a high potential side terminal of the upper arm rectifier unit are electrically connected to the high potential side DC terminal, low potential side terminals of the first, second and third lower arm switches and a low potential side terminal of the lower arm rectifier unit are electrically connected to the low potential side DC terminal, the first AC terminal of the first inductor is electrically connected to a first end of the first capacitor; the second AC terminal side of the second inductor is electrically connected to a first end of the second capacitor, the third AC terminal side of the third inductor is electrically connected to a first end of the third capacitor, second ends of the first capacitor, the second capacitor, and the third capacitor are electrically connected to each other; a second end of each of the first capacitor, the second capacitor, and the third capacitor is electrically connected to the DC side connection portion via the connection switch, The DC side connection portion is a connection point of a first DC side capacitor (34A) and a second DC side capacitor (34B) connected in series to electrically connect the high potential side DC terminal and the low potential side DC terminal; the high potential side DC terminal, or the low potential side DC terminal Either When the control unit determines that the single-phase AC power supply is connected to the first AC terminal and the fourth AC terminal, the control unit turns on the single-phase charging switch and turns off the connection switch, and performs switching control of the first upper arm switch and the first lower arm switch to perform power conversion between the first AC terminal and the fourth AC terminal and the high potential side DC terminal and the low potential side DC terminal.

2. 2. The power conversion device according to claim 1, wherein second ends of the first capacitor, the second capacitor, and the third capacitor are electrically connected to a connection point of the upper arm rectifier and the lower arm rectifier on a side of the connection path relative to the single-phase charging switch.

3. The power conversion device according to claim 1 or 2, wherein the upper arm rectifier and the lower arm rectifier allow current to flow from their own low potential side terminals to their own high potential side terminals.

4. the upper arm rectifier is a fourth upper arm switch (S4H) having an anti-parallel connected diode; The lower arm rectifier is a fourth lower arm switch (S4L) having an anti-parallel connected diode, The control unit when it is determined that the three-phase AC power supply is connected to the first AC terminal, the second AC terminal, and the third AC terminal, turning off the fourth upper arm switch and the fourth lower arm switch; 4. The power conversion device according to claim 3, wherein when it is determined that the single-phase AC power supply is connected to the first AC terminal and the fourth AC terminal, switching control is performed to alternately turn on the fourth upper arm switch and the fourth lower arm switch.

5. a first AC terminal (Tac1), a second AC terminal (Tac2), a third AC terminal (Tac3), and a fourth AC terminal (Tac4); a high potential side DC terminal (TdcH) and a low potential side DC terminal (TdcL); A computer (71); A power conversion device (10) comprising: A program applied to a power conversion device configured to allow a three-phase AC power supply (21) to be connected to the first AC terminal, the second AC terminal, and the third AC terminal, and to allow a single-phase AC power supply (22) to be connected to the first AC terminal and the fourth AC terminal, The power conversion device is a series connection of a first upper arm switch (S1H) and a first lower arm switch (S1L); a series connection of a second upper arm switch (S2H) and a second lower arm switch (S2L); a series connection of a third upper arm switch (S3H) and a third lower arm switch (S3L); a series connection of an upper arm rectifier unit (S4H, D4H) and a lower arm rectifier unit (S4L, D4L); a first inductor (31) electrically connecting a connection point between the first upper arm switch and the first lower arm switch and the first AC terminal; a second inductor (32) electrically connecting a connection point between the second upper arm switch and the second lower arm switch and the second AC terminal; a third inductor (33) electrically connecting a connection point between the third upper arm switch and the third lower arm switch and the third AC terminal; a connection path (44) electrically connecting a connection point between the upper arm rectifier and the lower arm rectifier and the fourth AC terminal; a single-phase charging switch (45) provided in the connection path; a first capacitor (161); a second capacitor (162); a third capacitor (163); A connection switch (151), DC side connection portions (34A, 34B, 34); Equipped with high potential side terminals of the first, second and third upper arm switches and a high potential side terminal of the upper arm rectifier unit are electrically connected to the high potential side DC terminal, low potential side terminals of the first, second and third lower arm switches and a low potential side terminal of the lower arm rectifier unit are electrically connected to the low potential side DC terminal, the first AC terminal of the first inductor is electrically connected to a first end of the first capacitor; the second AC terminal side of the second inductor is electrically connected to a first end of the second capacitor, the third AC terminal side of the third inductor is electrically connected to a first end of the third capacitor, second ends of the first capacitor, the second capacitor, and the third capacitor are electrically connected to each other; a second end of each of the first capacitor, the second capacitor, and the third capacitor is electrically connected to the DC side connection portion via the connection switch, The DC side connection portion is a connection point of a first DC side capacitor (34A) and a second DC side capacitor (34B) connected in series to electrically connect the high potential side DC terminal and the low potential side DC terminal; the high potential side DC terminal, or the low potential side DC terminal Either To the computer a process of determining whether the single-phase AC power supply is connected to the first AC terminal and the fourth AC terminal; a process of performing switching control of the first upper arm switch and the first lower arm switch to perform power conversion between the first AC terminal and the fourth AC terminal and the high potential side DC terminal and the low potential side DC terminal while turning on the single-phase charging switch and turning off the connection switch when it is determined that the single-phase AC power supply is connected to the first AC terminal and the fourth AC terminal; A program that executes.

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