Power converter, program

Abstract

To provide a power conversion device and a program that enables effective use of components.SOLUTION: A power conversion device 10 can comply with a three-way AC power source and a single-phase AC power source. The power conversion device 10 includes a connection path 44, a switch path 45, and first to third switches 61 to 63 as switch units to switch a state of the power conversion device 10 to a first state or a second state. In the first state, a high-potential side path 30H and a low-potential side path 30L are connected to each other with a serial connector of a first DC-side capacitor 34A and a second DC-side capacitor 34B and a neutral point, which is the connection point of first to third capacitors 51 to 53, is in electric connection to the connection point of the first DC-side capacitor 34A and the second DC-side capacitor 34B. In the second state, the neutral point is in electric connection to the connection path 44.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, a power conversion device compatible with both a three-phase AC power supply and a single-phase AC power supply has been known. As an example of such a power conversion device, the power conversion device disclosed in Patent Document 1 can be cited.

[0003] The power conversion device includes upper and lower arm switches provided corresponding to each of the three phases. The high-potential side terminals of the upper arm switches of each phase are connected to the high-potential side DC terminal, and the low-potential side terminals of the lower arm switches of each phase are connected to the low-potential side DC terminal. The high-potential side path and the low-potential side path are connected by a smoothing capacitor.

[0004] The power conversion device includes an inductor provided corresponding to each phase, and a compensation capacitor and a switching switch provided corresponding to any one of the phases. By operating the switching switch, the compensation capacitor is connected in parallel with a series connection of an inductor for one phase and a lower arm switch, or is disconnected from this series connection.

[0005] When a single-phase AC power supply is electrically connected to the AC terminal on the input side, the switching switch is operated so that the compensation capacitor is connected in parallel with a series connection of an inductor and a lower arm switch. In this operating state, switching control of the upper and lower arm switches of the phase to which the compensation capacitor is connected is performed. Thereby, when converting the AC power input from the AC terminal into DC power and outputting it from the DC terminal, the pulsation of the DC power output from the DC terminal can be reduced. Thereby, the capacitance of the smoothing capacitor can be reduced, and the smoothing capacitor can be miniaturized.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] U.S. Patent Application Publication No. 2011 / 0261591 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] When a three-phase AC power supply is electrically connected to the AC terminal, the changeover switch is operated to disconnect the compensating capacitor from the series connection of the inductor and the lower arm switch. In this case, the compensating capacitor is not used. Therefore, there is still room for improvement in the effective utilization of the components of the power converter.

[0008] The primary purpose of this disclosure is to provide a power conversion device and program that can effectively utilize its components. [Means for solving the problem]

[0009] This disclosure relates to a first AC terminal, a second AC terminal, a third AC terminal and a fourth AC terminal, High-potential DC terminal and low-potential DC terminal, Equipped with, In a power converter configured such that a three-phase AC section that carries three-phase alternating current is electrically connectable to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC section that carries single-phase alternating current is electrically connectable to the first AC terminal and the fourth AC terminal, First upper arm switch and first lower arm switch, The second upper arm switch and the second lower arm switch, The third upper arm switch and the third lower arm switch, A high-potential path connecting the high-potential terminals of the first, second, and third upper arm switches and the high-potential DC terminals, A low-potential path connecting the low-potential terminals of the first, second, and third lower arm switches and the low-potential DC terminals, A first path connecting the connection point of the first upper arm switch and the first lower arm switch to the first AC terminal, A second path connecting the connection point of the second upper arm switch and the second lower arm switch to the second AC terminal, A third path connecting the connection point of the third upper arm switch and the third lower arm switch to the third AC terminal, The first inductor provided in the first path, The second inductor provided in the second path, A third inductor provided in the third path, It is equipped with.

[0010] In order to reduce noise (specifically, common-mode noise, for example) when the upper and lower arm switches are being switched, the power converter is designed to reduce noise. The first capacitor, the second capacitor, and the third capacitor, A first DC capacitor and a second DC capacitor, It is equipped with.

[0011] The first terminal of the first capacitor is connected to the portion of the first path that is closer to the first AC terminal than the first inductor. The first end of the second capacitor is connected to the portion of the second path that is closer to the second AC terminal than the second inductor. The first end of the third capacitor is connected to the portion of the third path that is closer to the third AC terminal than the third inductor. The second terminals of the first capacitor, the second capacitor, and the third capacitor are connected to each other.

[0012] The power converter of this disclosure includes a switching unit that switches the state of the power converter between a first state and a second state.

[0013] In the first state, a series connection of the first DC-side capacitor and the second DC-side capacitor connects the high-potential side path and the low-potential side path, and the neutral point, which is the connection point between the second ends of the first, second, and third capacitors, is electrically connected to the connection point of the first DC-side capacitor and the second DC-side capacitor. When the state of the power conversion device is set to the first state when a three-phase AC section is electrically connected to the AC terminals, the above noise can be reduced.

[0014] On the other hand, in the second state, the neutral point is electrically connected to the fourth AC terminal. When the state of the power conversion device is set to the second state when a single-phase AC section is electrically connected to the AC terminals, either the first or second DC-side capacitor can be used as a compensation capacitor for reducing the pulsation of the DC power at each DC terminal. That is, the components of the power conversion device can be effectively utilized.

Brief Description of the Drawings

[0015] [Figure 1] Overall configuration diagram of the in-vehicle charger according to the first embodiment. [Figure 2] Diagram showing the in-vehicle charger during three-phase charging and discharging. [Figure 3] Diagram showing the in-vehicle charger during single-phase charging and discharging. [Figure 4] Flowchart showing the procedure for charging and discharging control of the storage battery. [Figure 5] Time chart showing the transition of current and voltage during three-phase charging control. [Figure 6] Time chart showing the transition of current and voltage during three-phase charging control according to the comparative example. [Figure 7] Block diagram of the pulsation compensation control process during single-phase charging control. [Figure 8] Time chart showing the transition of current, voltage, etc. during single-phase charging control. [Figure 9] Block diagram of the pulsation compensation control process during single-phase discharging control. [Figure 10] Overall configuration diagram of the in-vehicle charger according to the second embodiment. [Figure 11] A flowchart illustrating the procedure for controlling the charging and discharging of a storage battery. [Figure 12] Overall configuration diagram of the on-board charger according to the third embodiment. [Figure 13] A diagram showing an on-board charger during three-phase charging and discharging. [Figure 14] A diagram showing an on-board charger during single-phase charging and discharging. [Figure 15] This figure shows an on-board charger during three-phase charging and discharging according to the fourth embodiment. [Figure 16] A diagram showing an on-board charger during single-phase charging and discharging. [Figure 17] A flowchart illustrating the procedure for controlling the charging and discharging of a storage battery. [Figure 18] A diagram showing an on-board charger according to the fifth embodiment. [Figure 19] A diagram showing an on-board charger according to the sixth embodiment. [Figure 20] A flowchart illustrating the procedure for controlling the charging and discharging of a storage battery. [Figure 21] A diagram showing an on-board charger according to the seventh embodiment. [Figure 22] An overall configuration diagram of an in-vehicle charger according to another embodiment. [Modes for carrying out the invention]

[0016] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be given the same reference numeral, or reference numerals that differ by hundreds or more digits. For corresponding and / or related parts, refer to the descriptions of other embodiments.

[0017] <First Embodiment> Hereinafter, a first embodiment of the power conversion device according to the present invention will be described with reference to the drawings. The power conversion device according to this embodiment is installed in a vehicle such as an electric vehicle, and specifically is an AC-DC converter that constitutes an on-board charger. An on-board charger is also called an onboard charger.

[0018] The power converter is equipped with AC terminals and DC terminals. The power converter has the function of converting AC power input via the AC terminals connected to an AC power source outside the vehicle into DC power and outputting it from the DC terminals. The DC power output from the DC terminals is supplied to the vehicle's battery. The power converter also has the function of converting DC power input via the DC terminals into AC power and outputting it from the AC terminals. The AC power output from the AC terminals is supplied to the external power grid via an external AC power source. The power converter can be connected to a three-phase AC power source or a single-phase AC power source.

[0019] As shown in Figure 1, the power converter 10 is equipped with AC terminals: a first AC terminal Tac1, a second AC terminal Tac2, a third AC terminal Tac3, and a fourth AC terminal Tac4. Of the first to fourth AC terminals Tac1 to Tac4, the first to third AC terminals Tac1 to Tac3 can be connected to an external three-phase AC power supply 200, as shown in Figure 2. Of the first to fourth AC terminals Tac1 to Tac4, the first and fourth AC terminals Tac1 and Tac4 can be connected to an external single-phase AC power supply 210, as shown in Figure 3.

[0020] The power converter 10 is equipped with a high-potential DC terminal TdcH and a low-potential DC terminal TdcL as DC terminals. The high-potential DC terminal TdcH and the low-potential DC terminal TdcL are connected to the input section of a DC-DC converter 24 that constitutes an on-board charger. The output section of the DC-DC converter 24 is connected to a rechargeable battery 20 mounted on the vehicle. The DC-DC converter 24 transforms the DC voltage input from the high-potential DC terminal TdcH and the low-potential DC terminal TdcL and supplies the transformed DC voltage to the battery 20. The DC-DC converter 24 also transforms the DC voltage input from the battery 20 and supplies it to the high-potential DC terminal TdcH and the low-potential DC terminal TdcL. The DC-DC converter 24 is, for example, an isolated DC-DC converter in which the input section and output section are electrically isolated, and is equipped with a transformer that connects the input section and the output section.

[0021] The power converter 10 includes, as 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 (corresponding to the "upper arm rectifier section") and a fourth lower arm switch S4L (corresponding to the "lower arm rectifier section"). In this embodiment, each upper and lower arm switch S1H to S4L is an N-channel MOSFET having a body diode. Therefore, in each upper and lower arm switch 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.

[0022] The power converter 10 includes a high-potential path 30H, which is an electrical path connecting the high-potential terminals of the first, second, third, and fourth upper arm switches S1H, S2H, S3H, and S4H to the high-potential DC terminal TdcH, and a low-potential path 30L, which is an electrical path connecting the low-potential terminals of the first, second, third, and fourth lower arm switches S1L, S2L, S3L, and S4L to the low-potential DC terminal TdcL. The high-potential path 30H and the low-potential path 30L are conductive members such as busbars.

[0023] The power converter 10 includes a first path 41, a second path 42, and a third path 43. The first path 41 is an electrical path corresponding to the first phase, connecting the low-potential terminal of the first upper arm switch S1H and the high-potential terminal of the first lower arm switch S1L to the first AC terminal Tac1. The second path 42 is an electrical path corresponding to the second phase, connecting the low-potential terminal of the second upper arm switch S2H and the high-potential terminal of the second lower arm switch S2L to the second AC terminal Tac2. The third path 43 is an electrical path corresponding to the third phase, connecting the low-potential terminal of the third upper arm switch S3H and the high-potential terminal of the third lower arm switch S3L to the third AC terminal Tac3.

[0024] The power converter 10 includes a first inductor 31 provided in the first path 41, a second inductor 32 provided in the second path 42, and a third inductor 33 provided in the third path 43. The inductance values ​​of each inductor 31 to 33 may be the same, and the rated current (specifically, the temperature rise rated current) of each inductor 31 to 33 may be the same.

[0025] The power converter 10 is equipped with three capacitors, a first capacitor 51, a second capacitor 52, and a third capacitor 53, which are X capacitors, as a noise countermeasure during three-phase charge and discharge control. Each of the capacitors 51 to 53 is, for example, a film capacitor. The first terminal of the first capacitor 51 is connected to the portion of the first path 41 that is on the side of the first AC terminal Tac1 from the first inductor 31. The first terminal of the second capacitor 52 is connected to the portion of the second path 42 that is on the side of the second AC terminal Tac2 from the second inductor 32. The first terminal of the third capacitor 53 is connected to the portion of the third path 43 that is on the side of the third AC terminal Tac3 from the third inductor 33. The second terminals of the first capacitor 51, the second capacitor 52, and the third capacitor 53 are connected to each other. The connection point of the second terminals of each of the capacitors 51 to 53 is the neutral point.

[0026] The power converter 10 is equipped with a first DC-side capacitor 34A and a second DC-side capacitor 34B as noise countermeasures during three-phase charge / discharge control. The first DC-side capacitor 34A and the second DC-side capacitor 34B are, for example, film capacitors. A high-potential-side path 30H is connected to the first terminal of the first DC-side capacitor 34A.

[0027] The power converter 10 is equipped with a smoothing capacitor 35. The smoothing capacitor 35 is, for example, an electrolytic capacitor. The smoothing capacitor 35 connects the high-potential path 30H and the low-potential path 30L.

[0028] The power converter 10 includes a connection path 44, which is an electrical path connecting the low-potential terminal of the fourth upper arm switch S4H and the high-potential terminal of the fourth lower arm switch S4L to the fourth AC terminal Tac4.

[0029] The power converter 10 is equipped with a switching path 45. The first end of the switching path 45 is connected to the first end of the second DC side capacitor 34B. The second end of the second DC side capacitor 34B is connected to the low-potential side path 30L.

[0030] The power converter 10 includes a first changeover switch 61, a second changeover switch 62, and a third changeover switch 63. The first changeover switch 61 is a switch for electrically connecting or disconnecting the second terminal of the first DC side capacitor 34A and the first terminal of the second DC side capacitor 34B. When the first changeover switch 61 is turned on, the second terminal of the first DC side capacitor 34A and the first terminal of the second DC side capacitor 34B are connected in series. On the other hand, when the first changeover switch 61 is turned off, the second terminal of the first DC side capacitor 34A and the first terminal of the second DC side capacitor 34B are electrically disconnected.

[0031] The second changeover switch 62 is a switch for electrically connecting or disconnecting the portion of the third path 43 that is closer to the third AC terminal Tac3 than the third inductor 33, and the switching path 45. When the second changeover switch 62 is turned on, the third path 43 and the switching path 45 are electrically connected. On the other hand, when the second changeover switch 62 is turned off, the third path 43 and the switching path 45 are electrically disconnected.

[0032] The third changeover switch 63 is a switch for selectively connecting the second terminals of each capacitor 51 to 53 to either the connection path 44 or the switching path 45. When the third changeover switch 63 is controlled to the first state, the second terminals of each capacitor 51 to 53 are electrically connected to the switching path 45. On the other hand, when the third changeover switch 63 is controlled to the second state, the second terminals of each capacitor 51 to 53 are electrically connected to the connection path 44.

[0033] The power converter 10 is equipped with first to third current sensors 71 to 73. The first current sensor 71 detects the current flowing through the first inductor 31, the second current sensor 72 detects the current flowing through the second inductor 32, and the third current sensor 73 detects the current flowing through the third inductor 33. In this embodiment, the currents detected by the first, second, and third current sensors 71, 72, and 73 (hereinafter referred to as the first, second, and third current detection values ​​i1r, i2r, and i3r) are considered positive when they flow from the first, second, and third AC terminals Tac1, Tac2, and Tac3 to the first, second, and third inductors 31, 32, and 33.

[0034] The power converter 10 includes a first DC voltage sensor 81, a second DC voltage sensor 82, and an AC voltage sensor 83. The first DC voltage sensor 81 detects the voltage difference between the high-potential path 30H and the low-potential path 30L. The second DC voltage sensor 82 detects the terminal voltage of the second DC capacitor 34B. The AC voltage sensor 83 detects the voltage difference between the first AC terminal Tac1 and the fourth AC terminal Tac4. The detected values ​​from each of the sensors 71-73 and 81-83 are input to the control device 100 provided in the power converter 10.

[0035] The control device 100 is an electronic control unit (ECCU) mainly composed of a microcontroller 100a. The control device 100 is capable of exchanging information with a higher-level control device 101, which is more advanced than the control device 100. The higher-level control device 101 is an electronic control unit (ECCU) mainly composed of a microcontroller 101a and is located outside the power converter 10.

[0036] Each microcontroller 100a and 101a is equipped with a CPU (Central Processing Unit). The functions provided by each microcontroller 100a and 101a can be provided by software recorded in a physical memory device and the computer that executes it, by software only, by hardware only, or by a combination thereof. For example, if the microcontrollers 100a and 101a are provided by electronic circuits which are hardware, they can be provided by digital circuits including a large number of logic circuits, or by analog circuits. For example, the microcontrollers 100a and 101a execute programs stored in a non-transitory tangible storage medium which serves as their own storage unit. The program includes, for example, a processing program as shown in Figure 4, which will be described later. The method corresponding to the program is executed by executing a set of instructions that constitute the program. The storage unit is, for example, non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, OTA (Over The Air).

[0037] The control device 100 performs charge control, which supplies input power from the AC terminal to the battery 20 via the power converter 10 and the DC-DC converter 24, or discharge control, which outputs input power from the battery 20 to the AC terminal via the DC-DC converter 24 and the power converter 10. In this case, the DC-DC converter 24 is switched controlled by the control device 100. Note that the power converter 10 and the DC-DC converter 24 can each be controlled by their respective control devices. However, since individual control is not essential, Figure 1 shows a single control device 100 that controls both the power converter 10 and the DC-DC converter 24.

[0038] Outside the power converter 10, a first interruption switch 92A, a second interruption switch 92B, and a third interruption switch 92C are provided. In this embodiment, each of the interruption switches 92A to 92C is a relay. Each of the interruption switches 92A to 92C allows bidirectional current flow when turned ON and prevents bidirectional current flow when turned OFF. The first to third interruption switches 92A to 92C are connected to the first to third AC terminals Tac1 to Tac3.

[0039] As shown in Figure 2, a three-phase AC power supply 200 (corresponding to the "multi-phase AC section, three-phase AC section") can be electrically connected to the first to third AC terminals Tac1 to Tac3 via the first to third circuit breaker switches 92A to 92C. The three-phase AC power supply 200 is, for example, a grid power supply. In the three-phase AC power supply 200, the amplitude and frequency of the three-phase output voltages are the same, and the phase of the output voltage and output current is shifted by 120° in each phase. Although not shown, a three-phase AC load (corresponding to the "three-phase AC section") can be electrically connected to the first to third AC terminals Tac1 to Tac3 via the first to third circuit breaker switches 92A to 92C.

[0040] As shown in Figure 3, a single-phase AC power supply 210 (corresponding to the "single-phase AC section") can be electrically connected to the first AC terminal Tac1 and the fourth AC terminal Tac4 via the first circuit breaker switch 92A. In this embodiment, the amplitude of the output voltage of the single-phase AC power supply 210 is the same as the amplitude of the output voltage of the three-phase AC power supply 200. Also, the frequency of the output voltage of the single-phase AC power supply 210 is the same as the frequency of the output voltage of the three-phase AC power supply 200. Although not shown, a single-phase AC load (corresponding to the "single-phase AC section") can be electrically connected to the first AC terminal Tac1 and the fourth AC terminal Tac4 via the first circuit breaker switch 92A.

[0041] The control device 100 performs 3-phase / single-phase charging control or 3-phase / single-phase discharging control. This control will be explained below using the flowchart in Figure 4.

[0042] In step S10, it is determined whether an instruction for three-phase charging control or three-phase discharging control has been given. In this embodiment, an instruction transmitted from the higher-level control device 101 via CAN communication or the like is received, and based on the received instruction, it is determined whether an instruction for three-phase charging control or three-phase discharging control has been given.

[0043] The three-phase charging control is a control system that charges the battery 20 with power from the three-phase AC power supply 200 by switching control of the power converter 10 and the DC-DC converter 24, respectively.

[0044] Three-phase discharge control is a control method that supplies power from the battery 20 to a three-phase AC power supply 200, which is an external grid power supply, by switching control of the DC-DC converter 24 and the power converter 10. This control is also called V2G (Vehicle to Grid). Alternatively, three-phase discharge control is a control method that supplies power from the battery 20 to a three-phase AC load by switching control of the DC-DC converter 24 and the power converter 10. When the three-phase AC load is electrical equipment in a building such as a residence, this control is also called V2H (Vehicle to Home).

[0045] When a three-phase charge / discharge instruction is given, the first cutoff switch 92A, the second cutoff switch 92B, and the third cutoff switch 92C are turned on by the higher-level control device 101, as shown in Figure 2.

[0046] If a positive result is obtained in step S10, the process proceeds to step S11, and the first changeover switch 61 is turned on. This connects the high-potential path 30H and the low-potential path 30L through the series connection of the first DC-side capacitor 34A and the second DC-side capacitor 34B.

[0047] In step S12, the second changeover switch 62 is turned off. Also, the fourth upper arm switch S4H and the fourth lower arm switch S4L are turned off.

[0048] In step S13, the third changeover switch 63 is controlled so that the neutral point, which is the connection point between the second ends of each capacitor 51 to 53, is connected to the first end of the second DC side capacitor 34B (see Figure 2).

[0049] In step S14, three-phase charging control or three-phase discharging control is performed. First, regarding three-phase charging control, the first, second, and third upper arm switches S1H, S2H, S3H and the first, second, and third lower arm switches S1L, S2L, S3L are switched 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 DC terminal TdcH and the low-potential DC terminal TdcL. At this time, the switching control of each switch S1H, S2H, S3H, S1L, S2L, S3L is performed so that the voltage Vdcr detected by the first DC-side voltage sensor 81 is fed back to the target DC voltage VdcrefH (for example, 800V). In each phase, the upper arm switches and lower arm switches are turned on alternately with a dead time in between. In each phase, the switching period of the upper and lower arm switches is the same.

[0050] Next, regarding the three-phase discharge control, the DC power input from the high-potential DC terminal TdcH and the low-potential DC terminal TdcL is converted into AC power and output from the first AC terminal Tac1, the second AC terminal Tac2, and the third AC terminal Tac3. Switching control of the first, second, and third upper arm switches S1H, S2H, S3H and the first, second, and third lower arm switches S1L, S2L, S3L is performed. In each phase, the upper arm switches and lower arm switches are turned on alternately with a dead time in between. In each phase, the switching period of the upper and lower arm switches is the same.

[0051] In steps S11 to S13, the control of the first to third changeover switches 61 to 63 causes the power converter 10 to enter the first state. In the first state, the high-potential path 30H and the low-potential path 30L are connected by a series connection of the first DC-side capacitor 34A and the second DC-side capacitor 34B, and the neutral point, which is the connection point between the second ends of the first to third capacitors 51 to 53, is electrically connected to the connection point of the first DC-side capacitor 34A and the second DC-side capacitor 34B. In this case, the voltage to ground, which is the voltage of each DC terminal TdcH and TdcL with respect to the neutral point voltage of the three-phase AC power supply 200 (hereinafter referred to as the ground voltage), becomes stable. As a result, common-mode noise caused by stray capacitance etc. between the high-potential path 30H and the low-potential path 30L and the ground can be reduced.

[0052] Figure 5 shows the changes in the first, second, and third output voltages V1, V2, and V3, the first, second, and third current detection values ​​i1r, i2r, and i3r, the high-potential-side to-ground voltage Vdcp, and the low-potential-side to-ground voltage Vdcn of the three-phase AC power supply 200 during three-phase charging control. The first, second, and third output voltages V1, V2, and V3 are considered 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 200. The high-potential-side to-ground voltage Vdcp is the difference in voltage at the high-potential-side DC terminal TdcH relative to the ground voltage, and the low-potential-side to-ground voltage Vdcn is the difference in voltage at the low-potential-side DC terminal TdcL relative to the ground voltage.

[0053] As shown in Figure 5, three-phase charging control is performed such 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).

[0054] During three-phase charging control, the high-potential-side ground voltage Vdcp and the low-potential-side ground voltage Vdcn do not oscillate with the high-frequency switching frequency components of the first to third upper and lower arm switches S1H, S1L, S2H, S2L, S3H, and S3L. This is because the connection points on the second ends of the first to third capacitors 51 to 53, which are X capacitors, function as virtual neutral points. As a result, common-mode noise caused by stray capacitance between the high-potential-side path 30H, the low-potential-side path 30L, and ground can be reduced.

[0055] Figure 6 shows, as a comparative example, the case in which the second ends of the first to third capacitors 51 to 52 are electrically isolated from the switching path 45 during three-phase charging control. In this case, the connection points of the second ends of the first to third capacitors 51 to 53 and the connection points of each DC side capacitor 34A and 34B are electrically isolated. As a result, the high-potential side to ground voltage Vdcp and the low-potential side to ground voltage Vdcn oscillate with high-frequency switching frequency components.

[0056] Returning to the explanation in Figure 4, if a negative determination is made in step S10, the process proceeds to step S15, where it is determined whether or not an instruction for single-phase charging control or single-phase discharging control has been given based on the instruction received from the higher-level control device 101.

[0057] Single-phase charging control is a control method that charges the battery 20 with power from the single-phase AC power supply 210 by switching control of the power converter 10 and the DC-DC converter 24, respectively.

[0058] Single-phase discharge control is a control method that supplies power from the battery 20 to a single-phase AC load by switching control of the DC-DC converter 24 and the power converter 10. When the single-phase AC load is electrical equipment in a building such as a residence, this control is also called V2H.

[0059] When a single-phase charge / discharge instruction is given, as shown in Figure 3, the first cutoff switch 92A is turned on by the higher-level control device 101, and the second cutoff switch 92B and the third cutoff switch 92C are turned off by the higher-level control device 101.

[0060] If the result in step S15 is positive, proceed to step S16 and turn off the first changeover switch 61. In step S17, turn on the second changeover switch 62. This electrically connects the third path 43 and the switching path 45.

[0061] In step S18, the third changeover switch 63 is controlled so that the second ends of each capacitor 51-53 are connected to the connection path 44 (see Figure 3). The second upper arm switch S2H and the second lower arm switch S2L are turned off. As a result, the second DC side capacitor 34B becomes a compensation capacitor used in the pulsation compensation control described later. In steps S16 to S18, the control of the first to third changeover switches 61 to 63 causes the power converter 10 to enter the second state. In the second state, the neutral points of the first to third capacitors 51 to 53 are electrically connected to the fourth AC terminal Tac4 via the connection path 44, and the third path 43 is electrically connected to the changeover path 45.

[0062] In step S19, single-phase charging control or single-phase discharging control is performed. First, regarding single-phase charging control, the first upper arm switch S1H and the first lower arm switch S1L are switched 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 DC terminal TdcH and the low-potential DC terminal TdcL. At this time, the switching control of each switch S1H and S1L is performed so as to feed back the voltage Vdcr detected by the first DC-side voltage sensor 81 to a target DC voltage VdcrefL (for example, 400V, which is lower than VdcrefH). The first upper arm switch S1H and the first lower arm switch S1L are switched on alternately in synchronous order with a dead time in between. The switching period of the first upper and lower arm switches S1H and S1L is the same, and is the same as the switching period during three-phase charging control.

[0063] In single-phase charging control, during the first period when current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 210, the fourth lower arm switch S4L is turned on and the fourth upper arm switch S4H is turned off. On the other hand, during the second period when current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 210, 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 or second period can be determined, for example, based on the detected value of the first current sensor 71.

[0064] Next, regarding single-phase discharge control, the DC power input from the high-potential DC terminal TdcH and the low-potential DC terminal TdcL is converted into AC power and output from the first AC terminal Tac1 and the fourth AC terminal Tac4. Switching control of the first upper arm switch S1H and the first lower arm switch S1L is performed. The first upper arm switch S1H and the first lower arm switch S1L are turned on alternately in synchronous order with a dead time in between. The switching period of the first upper and lower arm switches S1H and S1L is the same, and is the same as the switching period during three-phase discharge control.

[0065] In single-phase discharge control, during the third period when current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 210, the fourth upper arm switch S4H is turned on and the fourth lower arm switch S4L is turned off. On the other hand, during the fourth period when current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 210, the fourth lower arm switch S4L is turned on and the fourth upper arm switch S4H is turned off. Whether the current timing falls within the third or fourth period can be determined, for example, based on the detected value of the first current sensor 71.

[0066] Furthermore, the switching period of the fourth upper and lower arm switches S4H and S4L is the same as the switching period of the output voltage of the single-phase AC power supply 210, and is longer than the switching period of the first, second, and third upper and lower arm switches S1H, S1L, S2H, S2L, S3H, and S3L during three-phase charge and discharge control. This is because, for the first to third phases, high-frequency switching (e.g., tens of kHz to hundreds of kHz) is required to reduce the ripple of the current flowing through the inductors 31 to 33, while for the fourth phase, switching at a frequency equivalent to the fundamental frequency of the output voltage of the single-phase AC power supply 210 (e.g., 50 Hz or 60 Hz) is sufficient.

[0067] During single-phase charging or single-phase discharging, pulsation compensation control is performed as switching control of the third upper arm switch S3H and the third lower arm switch S3L to reduce pulsation of the DC power transmitted through the high-potential DC terminal TdcH and the low-potential DC terminal TdcL. The third upper arm switch S3H and the third lower arm switch S3L are turned on alternately with a dead time in between. The switching period of the third upper and lower arm switches S3H and S3L is the same, and is the same as the switching period of the first and second upper and lower arm switches S1H, S1L, S2H and S2L.

[0068] Next, we will explain pulsation compensation control in single-phase charge / discharge control. Pulsation compensation control is a control method to reduce the pulsation of the DC power Pdc of the power converter 10. This control reduces the pulsation of the terminal voltage of the smoothing capacitor 35. Figure 7 is a block diagram showing an example of pulsation compensation control in single-phase charge control.

[0069] The target compensation voltage calculation unit 110 calculates the target compensation voltage Vcpref, which is the target value of the terminal voltage of the second DC-side capacitor 34B for reducing the pulsation of the DC power Pdc. Specifically, for example, the target compensation voltage calculation unit 110 calculates the target compensation voltage Vcpref based on the pulsation compensation amplitude Ppeak, the electrical angle θe, and the following equation (eq1).

[0070]

number

[0071] The voltage control unit 111 includes a compensation voltage deviation calculation unit 112 and a compensation voltage feedback control unit 113. The compensation voltage deviation calculation unit 112 calculates the compensation voltage deviation ΔVp by subtracting the terminal voltage of the second DC side capacitor 34B detected by the second DC side voltage sensor 82 (hereinafter referred to as the compensation voltage detection value Vcpr) from the target compensation voltage Vcpref. The compensation voltage feedback control unit 113 calculates the target feedback current I3fb as an manipulated variable for feedback control of the compensation voltage deviation ΔVp to 0. The feedback control in the compensation voltage feedback control unit 113 is, for example, proportional-integral control.

[0072] The feedforward current calculation unit 114 calculates the target feedforward current I3ff based on the pulsation compensation amplitude Ppeak, the electrical angle θe, and the following equation (eq2).

[0073]

number

[0074] The current control unit 115 comprises an adder 116, a compensation current deviation calculation unit 117, and a compensation current feedback control unit 118. The adder 116 calculates the target compensation current I3ref by adding the target feedforward current I3ff to the target feedback current I3fb. The feedforward current calculation unit 114 is not mandatory. In this case, "I3ref = I3fb".

[0075] The compensation current deviation calculation unit 117 calculates the compensation current deviation ΔIp by subtracting the third current detection value i3r detected by the third current sensor 73 from the target compensation current I3ref. The compensation current feedback control unit 118 calculates the third target voltage Vleg1ref3 as an manipulated variable for feedback control to reduce the compensation current deviation ΔIp to zero. The feedback control in the compensation current feedback control unit 118 is, for example, proportional-integral control.

[0076] The PWM generation unit 119 generates 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 based on a comparison of the magnitude of the third target voltage Vleg3ref with the carrier signal. By supplying the third upper and lower arm drive signals to the gates of the third upper and lower arm switches S3H and S3L, pulsation reduction control is performed.

[0077] In this embodiment, the connection path 44, the switching path 45, and the first to third changeover switches 61 to 63 correspond to the "switching section".

[0078] Figure 8 shows the changes in the compensation voltage detection value Vcpr, the output voltage Vac and output current iac of the single-phase AC power supply 210, the current icpr flowing through the second DC side capacitor 34B, the first current detection value i1r, the output power Pac of the single-phase AC power supply 210, the power Pcpr (=Vcpr × icpr) of the second DC side capacitor 34B, and the DC power Pdc output from each DC terminal TdcH and TdcL during single-phase charging control. The compensation voltage detection value Vcpr is considered positive when the voltage on the lower potential side path 30L is higher than the voltage on the switching path 45 side of the second DC side capacitor 34B. The output voltage Vac of the single-phase AC power supply 210 is considered positive when the voltage on the first AC terminal Tac1 is higher than the voltage on the fourth AC terminal Tac4 side. The output current iac of the single-phase AC power supply 210 is considered positive when it flows from the fourth AC terminal Tac4 side to the first AC terminal Tac1 side. The current icpr flowing through the second DC side capacitor 34B is considered positive when it flows from the switching path 45 to the low-potential side path 30L across both ends of the second DC side capacitor 34B.

[0079] As shown in Figure 8, single-phase charging control is performed such that the phase difference between the output voltage Vac of the single-phase AC power supply 210 and the first current detection value i1r becomes 0 (i.e., the power factor is 1) through high-frequency switching control of the first upper and lower arm switches S1H and S1L and low-frequency switching control of the fourth upper and lower arm switches S4H and S4L.

[0080] In the example shown in Figure 8, the output power Pac of the single-phase AC power supply 210 (i.e., the input power of the power converter 10) pulsates at a frequency twice the fundamental frequency of the output voltage Vac of the single-phase AC power supply 210. The third upper and lower arm switches S3H and S3L are switched to control the compensation voltage detection value Vcpr to be controlled to a target compensation voltage Vcpref for reducing this pulsating component. As a result, the pulsating component of the input power is absorbed as reactive power by the second DC-side capacitor 34B, and the DC power Pdc transmitted to each DC terminal TdcH and TdcL becomes approximately constant. Consequently, the capacitance of the smoothing capacitor 35 can be reduced, and the smoothing capacitor 35 can be miniaturized.

[0081] Next, using Figure 9, we will explain the pulsation compensation control in single-phase discharge control. In pulsation reduction control of single-phase discharge control, the parameter related to the electrical angle input to the target compensation voltage calculation unit 110 is changed from θ to "θ + 90°". This is to invert the sign of the power Pcpr (=Vcpr × icpr, see Figure 8) of the second DC side capacitor 34B.

[0082] According to the embodiment described above, when a single-phase AC power supply 210 is electrically connected to the first and fourth AC terminals Tac1 and Tac4, the second DC-side capacitor 34B for noise suppression can be used as a compensation capacitor for pulsation compensation control by controlling the first to third changeover switches 61 to 63. In other words, the components of the power converter 10 can be effectively utilized.

[0083] <Second Embodiment> The second embodiment will be described below, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the method for determining the 3-phase / single-phase charge / discharge control instruction in the control device 100 has been changed.

[0084] Figure 10 shows the overall configuration of the in-vehicle charger according to this embodiment.

[0085] The power converter 10 is equipped with a voltage detection circuit 84. The voltage detection circuit 84 detects the voltages of the first to third paths 41 to 43, using the voltage of the connection path 44 as a reference. The values ​​detected by the voltage detection circuit 84 are input to the control device 100.

[0086] Figure 11 shows a flowchart of the three-phase / single-phase charge / discharge control performed by the control device 100.

[0087] In step S20, the detected values ​​of the voltage detection circuit 84 are obtained when each of the cutoff switches 92A to 92C is turned ON.

[0088] In step S21, it is determined whether or not an instruction for 3-phase charging control or 3-phase discharging control has been given, based on the detected value of the voltage detection circuit 84. Specifically, if it is determined that AC voltage has been detected for two or more of the first to third phases, it is determined that an instruction for 3-phase charging control or 3-phase discharging control has been given.

[0089] In step S22, it is determined whether an instruction for single-phase charging control or single-phase discharging control has been given, based on the value detected by the voltage detection circuit 84. Specifically, if it is determined that an AC voltage has been detected only for the first phase among the first to third phases, it is determined that an instruction for single-phase charging control or single-phase discharging control has been given.

[0090] Incidentally, in steps S21 and S22, the instruction to perform either charge control or discharge control can be determined, for example, by receiving a preparation command transmitted from the higher-level control device 101 via CAN communication, and making a decision based on the received preparation command. In the case of a power converter 10 that does not perform discharge control, the process of determining whether to perform charge control or discharge control based on this preparation command is unnecessary, and the control device 100 itself can determine whether or not charge control has been instructed.

[0091] <Third Embodiment> The third embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, as shown in Figure 12, the connection relationships of the changeover switch and the changeover path have been changed.

[0092] The first end of the switching path 45 is connected to the second end of the first DC side capacitor 34A. The first changeover switch 64 is a switch for electrically connecting the first end of the second DC side capacitor 34B to the second end of the first DC side capacitor 34A and the switching path 45, or electrically disconnecting it from the second end of the first DC side capacitor 34A and the switching path 45.

[0093] The control device 100 performs three-phase / single-phase charge / discharge control. However, the following changes have been made to the process shown in Figure 4.

[0094] In step S13, as shown in Figure 13, the first changeover switch 64 is turned on so that the first terminal of the second DC side capacitor 34B is electrically connected to the second terminal of the first DC side capacitor 34A and the switching path 45. In step S18, as shown in Figure 14, the first changeover switch 64 is turned off so that the first terminal of the second DC side capacitor 34B is electrically disconnected from the second terminal of the first DC side capacitor 34A and the switching path 45.

[0095] In this embodiment, the second DC-side voltage sensor 82 detects the terminal voltage of the first DC-side capacitor 34A. The value detected by the second DC-side voltage sensor 82 is used as the compensation voltage detection value Vcpr in pulsation compensation control.

[0096] According to the embodiment described above, the same effects as those of the first embodiment can be achieved.

[0097] <Fourth Embodiment> The fourth embodiment will now be described, focusing on the differences from the third embodiment, with reference to the drawings. In this embodiment, as shown in Figures 15 and 16, the fourth upper arm switch S4H and the fourth lower arm switch S4L are not provided in the power converter 10.

[0098] In this embodiment, the connection path 44 connects the portion of the second path 42 that is closer to the second AC terminal Tac2 than the second inductor 32, to the fourth AC terminal Tac4.

[0099] The power converter 10 is equipped with a fourth changeover switch 65 located in the connection path 44. When the fourth changeover switch 65 is turned on, it electrically connects the second path 42 and the fourth AC terminal Tac4, and when it is turned off, it electrically disconnects the second path 42 and the fourth AC terminal Tac4. In this embodiment, the connection path 44, the changeover path 45, and the first to fourth changeover switches 61 to 63, 65 correspond to the "changeover section".

[0100] Figure 17 shows a flowchart of the three-phase / single-phase charge / discharge control performed by the control device 100.

[0101] In step S23, the second changeover switch 62 and the fourth changeover switch 65 are turned off, as shown in Figure 15.

[0102] In step S24, the second changeover switch 62 and the fourth changeover switch 65 are turned on, as shown in Figure 16.

[0103] In step S25, single-phase charging control or single-phase discharging control is performed. First, regarding single-phase charging control, the first upper arm switch S1H and the first lower arm switch S1L are switched 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 DC terminal TdcH and the low-potential DC terminal TdcL. At this time, the switching control of each switch S1H and S1L is performed so that the voltage Vdcr detected by the first DC voltage sensor 81 is fed back to the target DC voltage VdcrefL.

[0104] In single-phase charging control, during the first period when current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 210, the second lower arm switch S2L is turned on and the second upper arm switch S2H is turned off. On the other hand, during the second period when current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 210, the second upper arm switch S2H is turned on and the second lower arm switch S2L is turned off.

[0105] Next, regarding single-phase discharge control, the first upper arm switch S1H and the first lower arm switch S1L are switched to convert the DC power input from the high-potential DC terminal TdcH and the low-potential DC terminal TdcL into AC power and output it from the first AC terminal Tac1 and the fourth AC terminal Tac4.

[0106] In single-phase discharge control, during the third period when current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 210, the second upper arm switch S2H is turned on and the second lower arm switch S2L is turned off. On the other hand, during the fourth period when current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 210, the second lower arm switch S2L is turned on and the second upper arm switch S2H is turned off.

[0107] During single-phase charging control or single-phase discharging control, pulsation compensation control is performed as switching control of the third upper arm switch S3H and the third lower arm switch S3L to reduce pulsation of the DC power transmitted through the high-potential DC terminal TdcH and the low-potential DC terminal TdcL.

[0108] According to the embodiment described above, the number of components for pulsation compensation control that constitute the power converter 10 can be reduced.

[0109] <Fifth Embodiment> The fifth embodiment will now be described, focusing on the differences from the third and fourth embodiments, with reference to the drawings. In this embodiment, as with the fourth embodiment, the fourth upper arm switch S4H and the fourth lower arm switch S4L are not provided, as shown in Figure 18.

[0110] The control device 100 performs three-phase / single-phase charge / discharge control. However, the following changes have been made to the process shown in Figure 17. In step S11, the first changeover switch 64 is turned on. In step S16, the first changeover switch 61 is turned off.

[0111] In this embodiment, the second DC-side voltage sensor 82 detects the terminal voltage of the first DC-side capacitor 34A. The value detected by the second DC-side voltage sensor 82 is used as the compensation voltage detection value Vcpr in pulsation compensation control.

[0112] According to the embodiment described above, the same effects as those of the fourth embodiment can be achieved.

[0113] <Sixth Embodiment> The sixth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the configuration around the first changeover switch 66 has been changed, as shown in Figure 19.

[0114] The power converter 10 includes an inductor 36 and a first changeover switch 66. The first terminal of the inductor 36 is connected to the source of the fourth upper arm switch S4H and the drain of the fourth lower arm switch S4L. The first changeover switch 66 selectively connects the first terminal of the second DC side capacitor 34B to either the second terminal of the inductor 36 or the second terminal of the first DC side capacitor 34A.

[0115] The first end of the switching path 45 is connected to the second end of the first DC capacitor 34A. The connection path 44 connects the portion of the third path 43 that is closer to the third AC terminal Tac3 than the third inductor 33 to the fourth AC terminal Tac4. The connection path 44 is provided with a second changeover switch 62. In this embodiment, the connection path 44, switching path 45, second changeover switch 62, third changeover switch 63, and first changeover switch 66 correspond to the "switching section".

[0116] Next, using Figure 20, we will explain the three-phase / single-phase charge / discharge control performed by the control device 100.

[0117] In step S26, the first changeover switch 66 is controlled to connect the first terminal of the second DC capacitor 34B to the second terminal of the first DC capacitor 34A.

[0118] In step S27, the first changeover switch 66 is controlled to connect the first terminal of the second DC capacitor 34B to the second terminal of the inductor 36.

[0119] In step S28, single-phase charging control or single-phase discharging control is performed. First, regarding single-phase charging control, the first upper arm switch S1H and the first lower arm switch S1L are switched 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 DC terminal TdcH and the low-potential DC terminal TdcL. At this time, the switching control of each switch S1H and S1L is performed so that the voltage Vdcr detected by the first DC voltage sensor 81 is fed back to the target DC voltage VdcrefL.

[0120] In single-phase charging control, during the first period when current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 210, the third lower arm switch S3L is turned on and the third upper arm switch S3H is turned off. On the other hand, during the second period when current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 210, the third upper arm switch S3H is turned on and the third lower arm switch S3L is turned off.

[0121] Next, regarding single-phase discharge control, the first upper arm switch S1H and the first lower arm switch S1L are switched to convert the DC power input from the high-potential DC terminal TdcH and the low-potential DC terminal TdcL into AC power and output it from the first AC terminal Tac1 and the fourth AC terminal Tac4.

[0122] In single-phase discharge control, during the third period when current flows from the fourth AC terminal Tac4 to the first AC terminal Tac1 via the single-phase AC power supply 210, the third upper arm switch S3H is turned on and the third lower arm switch S3L is turned off. On the other hand, during the fourth period when current flows from the first AC terminal Tac1 to the fourth AC terminal Tac4 via the single-phase AC power supply 210, the third lower arm switch S3L is turned on and the third upper arm switch S3H is turned off.

[0123] In single-phase charging control or single-phase discharging control, the second upper arm switch S2H and the second lower arm switch S2L are turned off.

[0124] During single-phase charging control or single-phase discharging control, pulsation compensation control is performed as switching control of the fourth upper arm switch S4H and the fourth lower arm switch S4L to reduce pulsation of the DC power transmitted through the high-potential DC terminal TdcH and the low-potential DC terminal TdcL. In this embodiment, the second DC-side voltage sensor 82 detects the terminal voltage of the second DC-side capacitor 34B. The detected value of the second DC-side voltage sensor 82 is used as the compensation voltage detection value Vcpr in the pulsation compensation control.

[0125] According to the embodiment described above, effects similar to those of the first embodiment can be achieved.

[0126] <Seventh Embodiment> The following describes the seventh embodiment, focusing on the differences from the sixth embodiment, with reference to the drawings. In this embodiment, the configuration around the first changeover switch 66 has been changed, as shown in Figure 21.

[0127] The first changeover switch 66 selectively connects the second terminal of the first DC side capacitor 34A to either the second terminal of the inductor 60 or the first terminal of the second DC side capacitor 34B. The first terminal of the switching path 45 is connected to the first terminal of the second DC side capacitor 34B.

[0128] The control device 100 performs three-phase / single-phase charge / discharge control. However, the following changes are made to the process shown in Figure 20. In step S26, the first changeover switch 66 is controlled to connect the second terminal of the first DC side capacitor 34A to the first terminal of the second DC side capacitor 34B. In step S27, the first changeover switch 66 is controlled to connect the second terminal of the first DC side capacitor 34A to the second terminal of the inductor 36.

[0129] In this embodiment, the second DC-side voltage sensor 82 detects the terminal voltage of the first DC-side capacitor 34A. The value detected by the second DC-side voltage sensor 82 is used as the compensation voltage detection value Vcpr in pulsation compensation control.

[0130] According to the embodiment described above, the same effects as those of the sixth embodiment can be achieved.

[0131] <Other Embodiments> Furthermore, each of the above embodiments may be implemented with the following modifications.

[0132] The first upper arm switch may be composed of a parallel connection of multiple N-channel MOSFETs. The same applies to the first lower arm switch and the second to fourth upper and lower arm switches.

[0133] The upper and lower arm switches are not limited to N-channel MOSFETs; for example, an IGBT with freewheeling diodes connected in antiparallel may also be used. In this case, the collector of the IGBT corresponds to the high-potential terminal, and the emitter corresponds to the low-potential terminal.

[0134] Each DC-side capacitor is not limited to being composed of a single capacitor as shown in Figure 1, etc., but may also be composed of multiple capacitors connected in series.

[0135] • When single-phase charging control is performed, and bidirectional power conversion is not performed, but only unidirectional power conversion from AC power to DC power is performed, upper and lower arm diodes D4H and D4L (corresponding to the "upper and lower arm rectifier section") may be provided instead of the fourth upper and lower arm switches S4H and S4L, as shown in Figure 22. In this case, the cathode of each diode D4H and D4L corresponds to the high-potential side terminal, and the anode corresponds to the low-potential side terminal.

[0136] The mobile device on which the power converter is mounted is not limited to a vehicle; for example, it could be an aircraft or a ship. Furthermore, the mounting location of the power converter is not limited to a mobile device; it could be a stationary device.

[0137] The control device and control method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of Symbols]

[0138] 10...Power converter, 31-33...1st-3rd inductor, 34A, 34B...1st-2nd DC side capacitor, 51-53...1st-3rd capacitor, 61-63...1st-3rd changeover switch, 100...Control device, S1H, S2H, S3H, S4H...1st-4th upper arm switch, S1L, S2L, S3L, S4L...1st-4th lower arm switch.

Claims

1. The first AC terminal (Tac1), the second AC terminal (Tac2), the third AC terminal (Tac3), and the fourth AC terminal (Tac4), A high-potential DC terminal (TdcH) and a low-potential DC terminal (TdcL), Equipped with, In a power converter (10) configured such that a three-phase AC section (200) that carries three-phase alternating current is electrically connectable to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC section (210) that carries single-phase alternating current is electrically connectable to the first AC terminal and the fourth AC terminal, First upper arm switch (S1H) and first lower arm switch (S1L), The second upper arm switch (S2H) and the second lower arm switch (S2L), The third upper arm switch (S3H) and the third lower arm switch (S3L), A high-potential path (30H) connecting the high-potential terminals of the first, second, and third upper arm switches and the high-potential DC terminal, A low-potential path (30L) connecting the low-potential terminals of the first, second, and third lower arm switches and the low-potential DC terminal, A first path (41) connecting the connection point of the first upper arm switch and the first lower arm switch to the first AC terminal, A second path (42) connecting the connection point of the second upper arm switch and the second lower arm switch to the second AC terminal, A third path (43) connecting the connection point of the third upper arm switch and the third lower arm switch to the third AC terminal, The first inductor (31) provided in the first path, The second inductor (32) provided in the second path, A third inductor (33) provided in the third path, A first capacitor (51), a second capacitor (52), and a third capacitor (53), The first DC side capacitor (34A) and the second DC side capacitor (34B), Equipped with, The first terminal of the first capacitor is connected to the portion of the first path that is closer to the first AC terminal than the first inductor. The first end of the second capacitor is connected to the portion of the second path that is closer to the second AC terminal than the second inductor. The first end of the third capacitor is connected to the portion of the third path that is closer to the third AC terminal than the third inductor. The second terminals of the first capacitor, the second capacitor, and the third capacitor are connected to each other. The power converter is equipped with a switching unit (44, 45, 61-66) that switches the state of the power converter to a first state or a second state. The first state is a state in which the high-potential path and the low-potential path are connected by a series connection of the first DC-side capacitor and the second DC-side capacitor, and the neutral point, which is the connection point between the second ends of the first capacitor, the second capacitor and the third capacitor, is electrically connected to the connection point between the first DC-side capacitor and the second DC-side capacitor. The second state is a power converter in which the neutral point is electrically connected to the fourth AC terminal.

2. It comprises an upper arm rectifier (S4H, D4H) and a lower arm rectifier (S4L, D4L), The high-potential side terminal of the upper arm rectifier is connected to the high-potential side path. The low-potential side terminal of the lower arm rectifier is connected to the low-potential side path. The aforementioned switching unit is A connection path (44) connecting the connection point of the upper arm rectifier and the lower arm rectifier to the fourth AC terminal, Switching path (45), A first changeover switch (61), a second changeover switch (62), and a third changeover switch (63), Equipped with, The switching path is connected to the first terminal of the second DC capacitor. The second terminal of the second DC capacitor is connected to the low-potential path. The first terminal of the first DC capacitor is connected to the high-potential path. The first changeover switch is a switch that electrically connects or disconnects the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor. The second changeover switch is a switch that electrically connects or disconnects the portion of the third path that is closer to the third AC terminal than the third inductor and the changeover path. The power conversion device according to claim 1, wherein the third changeover switch is a switch that selectively connects the neutral point to the connection path or the changeover path.

3. It comprises an upper arm rectifier (S4H, D4H) and a lower arm rectifier (S4L, D4L), The high-potential side terminal of the upper arm rectifier is connected to the high-potential side path. The low-potential side terminal of the lower arm rectifier is connected to the low-potential side path. The aforementioned switching unit is A connection path (44) connecting the connection point of the upper arm rectifier and the lower arm rectifier to the fourth AC terminal, Switching path (45), A first changeover switch (64), a second changeover switch (62), and a third changeover switch (63), Equipped with, The switching path is connected to the second terminal of the first DC capacitor. The second terminal of the second DC capacitor is connected to the low-potential path. The first terminal of the first DC capacitor is connected to the high-potential path. The first changeover switch is a switch that electrically connects or disconnects the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor. The second changeover switch is a switch that electrically connects or disconnects the portion of the third path that is closer to the third AC terminal than the third inductor and the changeover path. The power conversion device according to claim 1, wherein the third changeover switch is a switch that selectively connects the neutral point to the connection path or the changeover path.

4. Equipped with a control device (100), The power conversion device according to claim 2 or 3, wherein the control device determines that the three-phase AC section is electrically connected to the first AC terminal, the second AC terminal, and the third AC terminal, controls the first changeover switch so that the second terminal of the first DC side capacitor is electrically connected to the first terminal of the second DC side capacitor, controls the second changeover switch so that the third path and the switching path are electrically disconnected, and controls the third changeover switch so that the neutral point and the switching path are electrically connected.

5. Equipped with a control device (100), The power conversion device according to claim 2 or 3, wherein the control device determines that the single-phase AC section is electrically connected to the first AC terminal and the fourth AC terminal, controls the first changeover switch so that the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor are electrically disconnected, controls the second changeover switch so that the third path and the changeover path are electrically connected, and controls the third changeover switch so that the neutral point and the connection path are electrically connected.

6. The power conversion device according to claim 5, wherein the control device is electrically connected to the first AC terminal and the fourth AC terminal, and when it determines that power is transmitted between the high-potential DC terminal and the low-potential DC terminal and the first AC terminal and the fourth AC terminal by switching control of the first upper arm switch and the first lower arm switch, it performs switching control of the third upper arm switch and the third lower arm switch in order to reduce the pulsation of the DC power transmitted to the high-potential DC terminal and the low-potential DC terminal.

7. In a program executed by a computer (100a) applied to a power converter (10), The aforementioned power converter is The first AC terminal (Tac1), the second AC terminal (Tac2), the third AC terminal (Tac3), and the fourth AC terminal (Tac4), A high-potential DC terminal (TdcH) and a low-potential DC terminal (TdcL), Equipped with, The power converter is configured such that a three-phase AC section (200) that carries three-phase alternating current can be electrically connected to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC section (210) that carries single-phase alternating current can be electrically connected to the first AC terminal and the fourth AC terminal. The aforementioned power converter is First upper arm switch (S1H) and first lower arm switch (S1L), The second upper arm switch (S2H) and the second lower arm switch (S2L), The third upper arm switch (S3H) and the third lower arm switch (S3L), Upper arm rectifier section (S4H, D4H) and lower arm rectifier section (S4L, D4L), A high-potential path (30H) connecting the high-potential terminals of the first, second, and third upper arm switches and the high-potential terminals of the upper arm rectifier section to the high-potential DC terminal, A low-potential path (30L) connecting the low-potential terminals of the first, second, and third lower arm switches and the low-potential terminals of the lower arm rectifier section to the low-potential DC terminal, A first path (41) connecting the connection point of the first upper arm switch and the first lower arm switch to the first AC terminal, A second path (42) connecting the connection point of the second upper arm switch and the second lower arm switch to the second AC terminal, A third path (43) connecting the connection point of the third upper arm switch and the third lower arm switch to the third AC terminal, The first inductor (31) provided in the first path, The second inductor (32) provided in the second path, A third inductor (33) provided in the third path, A first capacitor (51), a second capacitor (52), and a third capacitor (53), The first DC side capacitor (34A) and the second DC side capacitor (34B), A connection path (44) connecting the connection point of the upper arm rectifier and the lower arm rectifier to the fourth AC terminal, Switching path (45), A first changeover switch (61), a second changeover switch (62), and a third changeover switch (63), Equipped with, The first terminal of the first capacitor is connected to the portion of the first path that is closer to the first AC terminal than the first inductor. The first end of the second capacitor is connected to the portion of the second path that is closer to the second AC terminal than the second inductor. The first end of the third capacitor is connected to the portion of the third path that is closer to the third AC terminal than the third inductor. The second terminals of the first, second, and third capacitors are connected to each other. The switching path is connected to the first terminal of the second DC capacitor. The second terminal of the second DC capacitor is connected to the low-potential path. The first terminal of the first DC capacitor is connected to the high-potential path. The first changeover switch is a switch that electrically connects or disconnects the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor. The second changeover switch is a switch that electrically connects or disconnects the portion of the third path that is closer to the third AC terminal than the third inductor and the changeover path. The third changeover switch is a switch that selectively connects the neutral point, which is the connection point between the second ends of the first, second, and third capacitors, to the connection path or the changeover path. A program that, when it determines that the three-phase AC section is electrically connected to the first AC terminal, the second AC terminal, and the third AC terminal, controls the first changeover switch so that the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor are electrically connected, controls the second changeover switch so that the third path and the switching path are electrically disconnected, and controls the third changeover switch so that the neutral point and the switching path are electrically connected.

8. In a program executed by a computer (100a) applied to a power converter (10), The aforementioned power converter is The first AC terminal (Tac1), the second AC terminal (Tac2), the third AC terminal (Tac3), and the fourth AC terminal (Tac4), A high-potential DC terminal (TdcH) and a low-potential DC terminal (TdcL), Equipped with, The power converter is configured such that a three-phase AC section (200) that carries three-phase alternating current can be electrically connected to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC section (210) that carries single-phase alternating current can be electrically connected to the first AC terminal and the fourth AC terminal. The aforementioned power converter is First upper arm switch (S1H) and first lower arm switch (S1L), The second upper arm switch (S2H) and the second lower arm switch (S2L), The third upper arm switch (S3H) and the third lower arm switch (S3L), Upper arm rectifier section (S4H, D4H) and lower arm rectifier section (S4L, D4L), A high-potential path (30H) connecting the high-potential terminals of the first, second, and third upper arm switches and the high-potential terminals of the upper arm rectifier section to the high-potential DC terminal, A low-potential path (30L) connecting the low-potential terminals of the first, second, and third lower arm switches and the low-potential terminals of the lower arm rectifier section to the low-potential DC terminal, A first path (41) connecting the connection point of the first upper arm switch and the first lower arm switch to the first AC terminal, A second path (42) connecting the connection point of the second upper arm switch and the second lower arm switch to the second AC terminal, A third path (43) connecting the connection point of the third upper arm switch and the third lower arm switch to the third AC terminal, The first inductor (31) provided in the first path, The second inductor (32) provided in the second path, A third inductor (33) provided in the third path, A first capacitor (51), a second capacitor (52), and a third capacitor (53), The first DC side capacitor (34A) and the second DC side capacitor (34B), A connection path (44) connecting the connection point of the upper arm rectifier and the lower arm rectifier to the fourth AC terminal, Switching path (45), A first changeover switch (61), a second changeover switch (62), and a third changeover switch (63), Equipped with, The first terminal of the first capacitor is connected to the portion of the first path that is closer to the first AC terminal than the first inductor. The first end of the second capacitor is connected to the portion of the second path that is closer to the second AC terminal than the second inductor. The first end of the third capacitor is connected to the portion of the third path that is closer to the third AC terminal than the third inductor. The second terminals of the first, second, and third capacitors are connected to each other. The switching path is connected to the first terminal of the second DC capacitor. The second terminal of the second DC capacitor is connected to the low-potential path. The first terminal of the first DC capacitor is connected to the high-potential path. The first changeover switch is a switch that electrically connects or disconnects the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor. The second changeover switch is a switch that electrically connects or disconnects the portion of the third path that is closer to the third AC terminal than the third inductor and the changeover path. The third changeover switch is a switch that selectively connects the neutral point, which is the connection point between the second ends of the first, second, and third capacitors, to the connection path or the changeover path. A program that, when it determines that the single-phase AC section is electrically connected to the first AC terminal and the fourth AC terminal, controls the first changeover switch so that the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor are electrically disconnected, controls the second changeover switch so that the third path and the changeover path are electrically connected, and controls the third changeover switch so that the neutral point and the connection path are electrically connected.

9. In a program executed by a computer (100a) applied to a power converter (10), The aforementioned power converter is The first AC terminal (Tac1), the second AC terminal (Tac2), the third AC terminal (Tac3), and the fourth AC terminal (Tac4), A high-potential DC terminal (TdcH) and a low-potential DC terminal (TdcL), Equipped with, The power converter is configured such that a three-phase AC section (200) that carries three-phase alternating current can be electrically connected to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC section (210) that carries single-phase alternating current can be electrically connected to the first AC terminal and the fourth AC terminal. The aforementioned power converter is First upper arm switch (S1H) and first lower arm switch (S1L), The second upper arm switch (S2H) and the second lower arm switch (S2L), The third upper arm switch (S3H) and the third lower arm switch (S3L), Upper arm rectifier section (S4H, D4H) and lower arm rectifier section (S4L, D4L), A high-potential path (30H) connecting the high-potential terminals of the first, second, and third upper arm switches and the high-potential terminals of the upper arm rectifier section to the high-potential DC terminal, A low-potential path (30L) connecting the low-potential terminals of the first, second, and third lower arm switches and the low-potential terminals of the lower arm rectifier section to the low-potential DC terminal, A first path (41) connecting the connection point of the first upper arm switch and the first lower arm switch to the first AC terminal, A second path (42) connecting the connection point of the second upper arm switch and the second lower arm switch to the second AC terminal, A third path (43) connecting the connection point of the third upper arm switch and the third lower arm switch to the third AC terminal, The first inductor (31) provided in the first path, The second inductor (32) provided in the second path, A third inductor (33) provided in the third path, A first capacitor (51), a second capacitor (52), and a third capacitor (53), The first DC side capacitor (34A) and the second DC side capacitor (34B), A connection path (44) connecting the connection point of the upper arm rectifier and the lower arm rectifier to the fourth AC terminal, Switching path (45), A first changeover switch (64), a second changeover switch (62), and a third changeover switch (63), Equipped with, The first terminal of the first capacitor is connected to the portion of the first path that is closer to the first AC terminal than the first inductor. The first end of the second capacitor is connected to the portion of the second path that is closer to the second AC terminal than the second inductor. The first end of the third capacitor is connected to the portion of the third path that is closer to the third AC terminal than the third inductor. The second terminals of the first, second, and third capacitors are connected to each other. The switching path is connected to the second terminal of the first DC capacitor. The second terminal of the second DC capacitor is connected to the low-potential path. The first terminal of the first DC capacitor is connected to the high-potential path. The first changeover switch is a switch that electrically connects or disconnects the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor. The second changeover switch is a switch that electrically connects or disconnects the portion of the third path that is closer to the third AC terminal than the third inductor and the changeover path. The third changeover switch is a switch that selectively connects the neutral point, which is the connection point between the second ends of the first, second, and third capacitors, to the connection path or the changeover path. A program that, when it determines that the three-phase AC section is electrically connected to the first AC terminal, the second AC terminal, and the third AC terminal, controls the first changeover switch so that the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor are electrically connected, controls the second changeover switch so that the third path and the switching path are electrically disconnected, and controls the third changeover switch so that the neutral point and the switching path are electrically connected.

10. In a program executed by a computer (100a) applied to a power converter (10), The aforementioned power converter is The first AC terminal (Tac1), the second AC terminal (Tac2), the third AC terminal (Tac3), and the fourth AC terminal (Tac4), A high-potential DC terminal (TdcH) and a low-potential DC terminal (TdcL), Equipped with, The power converter is configured such that a three-phase AC section (200) that carries three-phase alternating current can be electrically connected to the first AC terminal, the second AC terminal, and the third AC terminal, and a single-phase AC section (210) that carries single-phase alternating current can be electrically connected to the first AC terminal and the fourth AC terminal. The aforementioned power converter is First upper arm switch (S1H) and first lower arm switch (S1L), The second upper arm switch (S2H) and the second lower arm switch (S2L), The third upper arm switch (S3H) and the third lower arm switch (S3L), Upper arm rectifier section (S4H, D4H) and lower arm rectifier section (S4L, D4L), A high-potential path (30H) connecting the high-potential terminals of the first, second, and third upper arm switches and the high-potential terminals of the upper arm rectifier section to the high-potential DC terminal, A low-potential path (30L) connecting the low-potential terminals of the first, second, and third lower arm switches and the low-potential terminals of the lower arm rectifier section to the low-potential DC terminal, A first path (41) connecting the connection point of the first upper arm switch and the first lower arm switch to the first AC terminal, A second path (42) connecting the connection point of the second upper arm switch and the second lower arm switch to the second AC terminal, A third path (43) connecting the connection point of the third upper arm switch and the third lower arm switch to the third AC terminal, The first inductor (31) provided in the first path, The second inductor (32) provided in the second path, A third inductor (33) provided in the third path, A first capacitor (51), a second capacitor (52), and a third capacitor (53), The first DC side capacitor (34A) and the second DC side capacitor (34B), A connection path (44) connecting the connection point of the upper arm rectifier and the lower arm rectifier to the fourth AC terminal, Switching path (45), A first changeover switch (64), a second changeover switch (62), and a third changeover switch (63), Equipped with, The first terminal of the first capacitor is connected to the portion of the first path that is closer to the first AC terminal than the first inductor. The first end of the second capacitor is connected to the portion of the second path that is closer to the second AC terminal than the second inductor. The first end of the third capacitor is connected to the portion of the third path that is closer to the third AC terminal than the third inductor. The second terminals of the first, second, and third capacitors are connected to each other. The switching path is connected to the second terminal of the first DC capacitor. The second terminal of the second DC capacitor is connected to the low-potential path. The first terminal of the first DC capacitor is connected to the high-potential path. The first changeover switch is a switch that electrically connects or disconnects the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor. The second changeover switch is a switch that electrically connects or disconnects the portion of the third path that is closer to the third AC terminal than the third inductor and the changeover path. The third changeover switch is a switch that selectively connects the neutral point, which is the connection point between the second ends of the first, second, and third capacitors, to the connection path or the changeover path. A program that, when it determines that the single-phase AC section is electrically connected to the first AC terminal and the fourth AC terminal, controls the first changeover switch so that the second terminal of the first DC side capacitor and the first terminal of the second DC side capacitor are electrically disconnected, controls the second changeover switch so that the third path and the changeover path are electrically connected, and controls the third changeover switch so that the neutral point and the connection path are electrically connected.

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