Bidirectional charger

Abstract

To provide a bidirectional charger capable of charging batteries or supplying single-phase three-wire system power, in which noise input to a commercial power source side is reduced during battery charging.SOLUTION: A bidirectional power charger Ch is configured to include: a bidirectional power conversion circuit PC1 that converts DC power supplied from a battery B to AC power when supplying single-phase three-wire system power, and outputs the AC power to a load Loα via an input / output terminal T1 on a hot side and a neutral terminal Tn; and a bidirectional power conversion circuit PC2 that converts DC power supplied from the battery B to AC power when supplying single-phase three-wire system power, and outputs the AC power to a load Loβ via an input / output terminal T2 and a neutral terminal Tn, in which each of the bidirectional power conversion circuits PC1 and PC2 includes a totem-pole type bidirectional inverter circuit INV with an inductor on only one of a plurality of arms and a bidirectional DC-DC converter circuit CNV.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bidirectional charger. [Background technology]

[0002] Some bidirectional chargers include two bidirectional power conversion circuits. When charging a battery, each bidirectional power conversion circuit converts AC power supplied from a commercial power source via a hot-side voltage line and a cold-side voltage line into DC power and outputs the DC power to the battery. When supplying power using a single-phase three-wire system, one bidirectional power conversion circuit converts DC power supplied from the battery into AC power and outputs it to one load via the hot-side voltage line and the ground-side neutral line, while the other bidirectional power conversion circuit converts DC power supplied from the battery into AC power and outputs it to the other load via the cold-side voltage line and the neutral line. Patent Document 1 describes a related technique.

[0003] However, when a bidirectional power conversion circuit includes a bidirectional inverter circuit and a bidirectional DC-DC converter circuit and each arm of the bidirectional inverter circuit has an inductor, there is a concern that noise may be generated in each inductor due to switching of the switching elements in the bidirectional inverter circuit.

[0004] In the above-described bidirectional charger, when each bidirectional inverter circuit of each bidirectional power conversion circuit has an inductor in each arm, the inductor is connected to the hot-side voltage line, the cold-side voltage line, and the neutral line, respectively. If power factor correction is performed during charging, the potential on the switching element side of each inductor fluctuates when the switching elements are switched, generating relatively large noise, which may be input to the commercial power supply side when the battery is being charged. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-78350 Summary of the Invention [Problem to be solved by the invention]

[0006] An object according to one aspect of the present invention is to reduce noise input to the commercial power supply side when charging a battery in a bidirectional charger capable of charging a battery or supplying single-phase three-wire power. [Means for solving the problem]

[0007] A bidirectional charger according to one embodiment of the present invention includes a first input / output terminal connected to a first load, a second input / output terminal connected to a second load connected in series with the first load, a neutral terminal connected to a connection point between the first load and the second load and grounded, a first switch, a second switch, a first bidirectional inverter circuit connected to the first input / output terminals and one end of the first switch, a second bidirectional inverter circuit connected to the second input / output terminals and one end of the second switch, a first bidirectional DCDC converter circuit that converts DC power supplied from the first bidirectional inverter circuit into DC power of a different voltage and outputs it to a battery, and converts DC power supplied from the battery into DC power of a different voltage and outputs it to the first bidirectional inverter circuit, a second bidirectional DCDC converter circuit that converts DC power supplied from the second bidirectional inverter circuit into DC power of a different voltage and outputs it to the battery, and converts DC power supplied from the battery into DC power of a different voltage and outputs it to the second bidirectional inverter circuit, and a first bidirectional inverter circuit, the first bidirectional inverter circuit, the second bidirectional inverter circuit, and the first bidirectional inverter circuit. a control unit that controls a one-way DC-DC converter circuit, the second bidirectional DC-DC converter circuit, the first switch, and the second switch, wherein the other end of the first switch is switchably connected to either the neutral terminal or the second input / output terminal, and the other end of the second switch is switchably connected to either the neutral terminal or the first input / output terminal; the first bidirectional inverter circuit includes a first arm in which a first switching element and a second switching element are connected in series, a second arm in which a third switching element and a fourth switching element are connected in series, and a first coil having one end connected to a connection point between the first switching element and the second switching element and the other end connected to either the first input / output terminal or one end of the first switch, the first arm and the second arm being connected in parallel, and the connection point between the third switching element and the fourth switching element being connected to the other of the first input / output terminal and one end of the first switch;a fourth arm in which a seventh switching element and an eighth switching element are connected in series; and a second coil having one end connected to a connection point between the fifth switching element and the sixth switching element and the other end connected to either the second input / output terminal or one end of the second switch, wherein the third arm and the fourth arm are connected in parallel, and the connection point between the seventh switching element and the eighth switching element is connected to the other of the second input / output terminal or one end of the second switch.

[0008] This allows the bidirectional inverter circuits included in the first and second bidirectional power conversion circuits to be configured as totem-pole bidirectional inverter circuits, thereby reducing the number of inductors connected to the hot-side voltage line, the cold-side voltage line, and the neutral line.As a result, it is possible to reduce noise generated in each inductor due to switching of the switching elements in the bidirectional inverter circuits when charging the battery, and to reduce noise input to the commercial power supply when charging the battery.

[0009] The control unit may be configured to perform control so that, during single-phase three-wire power supply, the first coil of the first bidirectional inverter circuit is connected to the first input / output terminal and the second coil of the second bidirectional inverter circuit is connected to the neutral terminal.

[0010] The control unit may be configured to perform control so that, during single-phase three-wire power supply, the first coil of the first bidirectional inverter circuit is connected to the neutral terminal and the second coil of the second bidirectional inverter circuit is connected to the neutral terminal.

[0011] Furthermore, the control unit may be configured to perform control so that, during single-phase three-wire power supply, the first coil of the first bidirectional inverter circuit is connected to the first input / output terminal and the second coil of the second bidirectional inverter circuit is connected to the second input / output terminal.

[0012] The first bidirectional inverter circuit may include a fifth arm connected in parallel to the first arm and the second arm, and in which a ninth switching element and a tenth switching element are connected in series, and a third coil, one end of the third coil being connected to a connection point between the ninth switching element and the tenth switching element, and the other end being connected to either the first input / output terminal or one end of the first switch; and the second bidirectional inverter circuit may include a sixth arm connected in parallel to the third arm and the fourth arm, and in which an eleventh switching element and a twelfth switching element are connected in series, and a fourth coil, one end of the fourth coil being connected to a connection point between the eleventh switching element and the twelfth switching element, and the other end being connected to either the second input / output terminal or one end of the second switch.

[0013] This allows the bidirectional inverter circuit to be configured with an interleaved bidirectional inverter circuit, which increases the number of arms of the bidirectional inverter circuit, thereby increasing the power output to the battery when charging the battery and the power output to the load when supplying power in a single-phase three-wire system. [Effects of the Invention]

[0014] According to the present invention, in a bidirectional charger capable of charging a battery or supplying single-phase three-wire power, it is possible to reduce noise input to the commercial power supply side when charging a battery. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a diagram illustrating an example of a bidirectional charger according to an embodiment. [Figure 2] FIG. 1 is a diagram illustrating an example of a bidirectional DC-DC converter circuit. [Figure 3] FIG. 10 is a diagram showing a first modified example of the bidirectional charger according to the embodiment. [Figure 4] FIG. 10 is a diagram showing a second modified example of the bidirectional charger according to the embodiment. [Figure 5]FIG. 10 is a diagram showing a third modified example of the bidirectional charger according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0017] FIG. 1 is a diagram illustrating an example of a bidirectional charger according to an embodiment.

[0018] The bidirectional charger Ch shown in FIG. 1 is mounted on a vehicle such as an electric vehicle or a plug-in hybrid vehicle, and has the following functions: converting AC power supplied from a commercial power source into DC power and outputting the DC power to a battery B mounted on the vehicle to charge the battery B; and converting DC power supplied from the battery B into AC power and supplying the AC power to a load such as an electrical appliance via a single-phase three-wire system to drive the load.

[0019] The bidirectional charger Ch also includes an input / output terminal T1 (first input / output terminal) connected to a load Loα (first load), an input / output terminal T2 (second input / output terminal) connected to a load Loβ (second load) connected in series with the load Loα, and a neutral terminal Tn connected to the connection point between the load Loα and the load Loβ and grounded. The load Loα and the load Loβ may be directly connected to the input / output terminal T1, the input / output terminal T2, and the neutral terminal Tn, or may be connected via wiring. The loads Loα and Loβ are assumed to be electrical appliances that operate on AC 100V. The current consumptions of the loads Loα and Loβ are assumed to be Iα and Iβ, respectively. Therefore, when the current consumption Iα flows through the load Loα at AC 100V, this is the power consumption α, and when the current consumption Iβ flows through the load Loβ at AC 100V, this is the power consumption β. The power consumptions α and β are not necessarily constant but may change as the current consumption changes. There may be cases where the power consumption α and the power consumption β are the same value, where the power consumption α is greater than the power consumption β, or where the power consumption α is less than the power consumption β. When there is no distinction between the loads Loα and Loβ, they are simply referred to as the load Lo.

[0020] When charging the battery B, power is supplied to the bidirectional charger Ch from a commercial power supply (not shown) connected between the hot-side input / output terminal T1 and the cold-side input / output terminal T2.

[0021] Battery B is a rechargeable battery such as a lithium ion secondary battery, and is, for example, a rechargeable battery for supplying power to a drive device such as a traction motor, or a rechargeable battery for supplying power to electrical equipment such as an air compressor or a vehicle-side control unit that controls the operation of the vehicle.

[0022] The bidirectional charger Ch also includes a changeover switch SW1 (first switch), a changeover switch SW2 (second switch), a bidirectional power conversion circuit PC1 (first bidirectional power conversion circuit), a bidirectional power conversion circuit PC2 (second bidirectional power conversion circuit), and a control unit CNT.

[0023] When charging battery B, selector switches SW1 and SW2 connect bidirectional power conversion circuits PC1 and PC2 between input / output terminals T1 and T2, respectively. Furthermore, when charging battery B, a commercial power supply is connected between input / output terminals T1 and T2. Therefore, when charging battery B, power can be supplied from the commercial power supply to battery B via bidirectional power conversion circuits PC1 and PC2. This allows the power supplied to battery B to be increased compared to when power is supplied to battery B from the commercial power supply via only one bidirectional power conversion circuit, thereby shortening the charging time of battery B.

[0024] Furthermore, during single-phase three-wire power supply, the changeover switches SW1 and SW2 connect the bidirectional power conversion circuit PC1 between the input / output terminal T1 and the neutral terminal Tn, and connect the bidirectional power conversion circuit PC2 between the input / output terminal T2 and the neutral terminal Tn.

[0025] <Configuration of bidirectional power conversion circuits PC1 and PC2> The bidirectional power conversion circuit PC1 includes a bidirectional inverter circuit INV1 (first bidirectional inverter circuit) and a bidirectional DCDC converter circuit CNV1 (first bidirectional DCDC converter circuit), and the bidirectional power conversion circuit PC2 includes a bidirectional inverter circuit INV2 (second bidirectional inverter circuit) and a bidirectional DCDC converter circuit CNV2 (second bidirectional DCDC converter circuit).When the bidirectional inverter circuits INV1 and INV2 are not distinguished, they are simply referred to as the bidirectional inverter circuit INV, and when the bidirectional DCDC converter circuits CNV1 and CNV2 are not distinguished, they are simply referred to as the bidirectional DCDC converter circuit CNV.

[0026] <Example of operation of bidirectional inverter circuits INV1, INV2 and bidirectional DC-DC converter circuits CNV1, CNV2 when charging battery B> When charging battery B, the bidirectional inverter circuit INV1 converts AC power supplied from the commercial power supply into DC power and outputs it to the bidirectional DCDC converter circuit CNV1, and the bidirectional DCDC converter circuit CNV1 converts the DC power output from the bidirectional inverter circuit INV1 into DC power of a different voltage and outputs it to battery B. When charging battery B, the bidirectional inverter circuit INV2 converts AC power supplied from the commercial power supply into DC power and outputs it to the bidirectional DCDC converter circuit CNV2, and the bidirectional DCDC converter circuit CNV2 converts the DC power output from the bidirectional inverter circuit INV2 into DC power of a different voltage and outputs it to battery B. That is, when charging battery B, the bidirectional power conversion circuits PC1 and PC2 convert AC power supplied from the commercial power supply via the input / output terminals T1 and T2, respectively, into DC power and output it to battery B.

[0027] <Example of operation of bidirectional inverter circuits INV1, INV2 and bidirectional DC-DC converter circuits CNV1, CNV2 when power is supplied via a single-phase three-wire system> The bidirectional power conversion circuit PC1 is controlled so that 100V AC is applied between the input / output terminal T1 and the neutral terminal Tn, and the bidirectional power conversion circuit PC2 is controlled so that 100V AC is applied between the input / output terminal T2 and the neutral terminal Tn. As mentioned above, the loads Loα and Loβ are devices that operate at 100V AC, and their respective current consumptions are Iα and Iβ. Therefore, when the consumption current Iα flows through the load Loα at 100V AC, this is the power consumption α, and when the consumption current Iβ flows through the load Loβ at 100V AC, this is the power consumption β.

[0028] When a load Loα is connected only between the input / output terminal T1 and the neutral terminal Tn during single-phase, three-wire power supply, the bidirectional DC-DC converter circuit CNV1 converts the DC power supplied from battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV1. The bidirectional inverter circuit INV1 controls the DC power output from the bidirectional DC-DC converter circuit CNV1 so that a consumption current Iα flows at 100V AC. In other words, the bidirectional power conversion circuit PC1 converts the DC power equivalent to the power consumption α of the load Loα and outputs that AC power to the load Loα via the input / output terminal T1 and the neutral terminal Tn. This allows the load Loα to be driven. Note that the bidirectional power conversion circuit PC2 generates 100V AC between the neutral terminal Tn and the input / output terminal T2, but no current flows.

[0029] Furthermore, when a load Loβ is connected only between the input / output terminal T2 and the neutral terminal Tn during single-phase, three-wire power supply, the bidirectional DC-DC converter circuit CNV2 converts the DC power supplied from battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV2. The bidirectional inverter circuit INV2 controls the DC power output from the bidirectional DC-DC converter circuit CNV2 so that a consumption current Iβ flows at 100V AC. In other words, the bidirectional power conversion circuit PC2 converts the DC power into AC power equivalent to the power consumption β of the load Loβ and outputs that AC power to the load Loβ via the input / output terminal T2 and the neutral terminal Tn. This allows the load Loβ to be driven. Note that the bidirectional power conversion circuit PC1 generates 100V AC between the input / output terminal T1 and the neutral terminal Tn, but no current flows.

[0030] During single-phase three-wire power supply, when a load Loα is connected between input / output terminal T1 and neutral terminal Tn and a load Loβ is connected between input / output terminal T2 and neutral terminal Tn, bidirectional DC-DC converter circuit CNV1 converts DC power supplied from battery B to DC power of a different voltage and outputs it to bidirectional inverter circuit INV1, which controls the DC power output from bidirectional DC-DC converter circuit CNV1 to flow a consumption current Iα at 100V AC. In other words, bidirectional power conversion circuit PC1 converts DC power supplied from battery B to AC power equivalent to the consumption current α and outputs that AC power to load Loα. Similarly, bidirectional DC-DC converter circuit CNV2 converts DC power supplied from battery B to DC power of a different voltage and outputs it to bidirectional inverter circuit INV2, which controls the DC power output from bidirectional DC-CDC converter circuit CNV2 to flow a consumption current Iβ at 100V AC. That is, the bidirectional power conversion circuit PC2 converts the DC power supplied from the battery B into AC power equivalent to the power consumption β and outputs the AC power to the load Loβ. This allows the load Loα and the load Loβ to be driven simultaneously.

[0031] <Configuration of bidirectional inverter circuit INV1> The bidirectional inverter circuit INV1 is a totem-pole bidirectional inverter circuit having an inductor in only one of its two arms, and includes an inductor L11 (first coil), a switching element Q11 (first switching element), a switching element Q12 (second switching element), a switching element Q13 (third switching element), a switching element Q14 (fourth switching element), a capacitor C1, voltage sensors Sv11 and Sv12, and a current sensor Si11. For example, the switching elements Q11 to Q14 are configured by MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The switching elements Q11 and Q12 configure a first arm, and the switching elements Q13 and Q14 configure a second arm.

[0032] One end of inductor L11 is connected to input / output terminal T1, and the other end of inductor L11 is connected to the connection point between the source terminal of switching element Q11 and the drain terminal of switching element Q12. The connection point between the source terminal of switching element Q13 and the drain terminal of switching element Q14 is connected to input / output terminal T2 and neutral terminal Tn via selector switch SW1. The drain terminals of switching elements Q11 and Q13 are connected to each other and to one end of capacitor C1. The source terminals of switching elements Q12 and Q14 are connected to each other and to the other end of capacitor C1.

[0033] The voltage sensor Sv11 detects the voltage applied between the input / output terminal T1 and the input / output terminal T2 when the battery B is being charged, and detects the voltage applied between the input / output terminal T1 and the neutral terminal Tn when single-phase three-wire power is being supplied, and sends these detected voltages to the control unit CNT.

[0034] The voltage sensor Sv12 detects the voltage across the capacitor C1 when the battery B is being charged or when power is being supplied through a single-phase three-wire system, and sends the detected voltage to the control unit CNT.

[0035] The current sensor Si11 detects the current flowing through the inductor L11 when the battery B is being charged or when power is being supplied through a single-phase three-wire system, and sends the detected current to the control unit CNT.

[0036] <Configuration of bidirectional inverter circuit INV2> Like the bidirectional inverter circuit INV1, the bidirectional inverter circuit INV2 is a totem-pole bidirectional inverter circuit having an inductor in only one of its two arms. The bidirectional inverter circuit INV2 includes an inductor L21 (second coil), a switching element Q21 (fifth switching element), a switching element Q22 (sixth switching element), a switching element Q23 (seventh switching element), a switching element Q24 (eighth switching element), a capacitor C2, voltage sensors Sv21 and Sv22, and a current sensor Si21. For example, the switching elements Q21 to Q24 are configured with MOSFETs. When inductors L11 and L21 are not distinguished, they are simply referred to as inductor L. When inductors Q11 to Q14 and Q21 to Q24 are not distinguished, they are simply referred to as switching element Q. The switching elements Q21 and Q22 form a third arm, and the switching elements Q23 and Q24 form a fourth arm.

[0037] One end of inductor L21 is connected to input / output terminal T1 and neutral terminal Tn via selector switch SW2. The junction between the source terminal of switching element Q21 and the drain terminal of switching element Q22 is connected to the other end of inductor L21. The junction between the source terminal of switching element Q23 and the drain terminal of switching element Q24 is connected to input / output terminal T2. The drain terminals of switching elements Q21 and Q23 are connected to each other and to one end of capacitor C2. The source terminals of switching elements Q22 and Q24 are connected to each other and to the other end of capacitor C2.

[0038] The voltage sensor Sv21 detects the voltage applied between the input / output terminal T1 and the input / output terminal T2 when the battery B is being charged, and detects the voltage applied between the input / output terminal T2 and the neutral terminal Tn when single-phase three-wire power is being supplied, and sends these detected voltages to the control unit CNT.

[0039] The voltage sensor Sv22 detects the voltage across the capacitor C2 when the battery B is being charged or when power is being supplied through a single-phase three-wire system, and sends the detected voltage to the control unit CNT.

[0040] The current sensor Si21 detects the current flowing through the inductor L21 when the battery B is being charged or when power is being supplied through a single-phase three-wire system, and sends the detected current to the control unit CNT.

[0041] In this way, the bidirectional inverter circuits INV included in the bidirectional power conversion circuits PC1 and PC2 are totem-pole bidirectional inverter circuits, and the number of inductors L connected to the input / output terminals T1, T2, and neutral terminal Tn can be reduced, and the number of switching elements connected to the inductors L can also be reduced. This reduces the number of locations where fluctuations in the potential on the switching element side of the inductor L occur when the switching elements are switched during power factor correction operation during charging. This reduces noise generated by the switching of the switching element Q in the bidirectional inverter circuit INV when charging the battery B, and reduces noise input to the commercial power supply when charging the battery B.

[0042] <Configuration of control unit CNT> The control unit CNT is configured by, for example, a processor or a programmable device (such as an FPGA (Field Programmable Gate Array) or a PLD (Programmable Logic Device)), and controls the operations of the changeover switches SW1 and SW2 and the bidirectional power conversion circuits PC1 and PC2. Note that the control unit CNT may be configured by multiple control units, such as a control unit that controls the operations of the changeover switches SW1 and SW2, a control unit that controls the operation of the bidirectional power conversion circuit PC1, and a control unit that controls the operation of the bidirectional power conversion circuit PC2.

[0043] <Example of operation control of bidirectional inverter circuit INV1 when charging battery B> When the current detected by the current sensor Si11 is positive (when a current flows from the input / output terminal T1 to the switching elements Q11 and Q12 via the inductor L11), the control unit CNT keeps the switching element Q14 always on and the switching element Q13 always off, turns the switching element Q12 on and turns the switching element Q11 off, and then repeatedly turns the switching element Q12 off and turns the switching element Q11 on.When the current detected by the current sensor Si11 is negative (when a current flows from the switching elements Q11 and Q12 to the input / output terminal T1 via the inductor L11), the control unit CNT keeps the switching element Q13 always on and the switching element Q14 always off, turns the switching element Q11 on and turns the switching element Q12 off, and then repeatedly turns the switching element Q11 off and turns the switching element Q12 on. As a result, when charging battery B, the AC power input from the commercial power supply to the bidirectional inverter circuit INV1 via the input / output terminals T1 and T2 is power factor corrected and rectified, and the rectified power is smoothed by capacitor C1 and output to the bidirectional DC-DC converter circuit CNV1.

[0044] <Example of operation control of bidirectional inverter circuit INV2 when charging battery B> When the current detected by the current sensor Si21 is positive (when a current flows from the input / output terminal T1 to the switching elements Q21 and Q22 via the inductor L21), the control unit CNT keeps switching element Q24 always on and switching element Q23 always off, turns on switching element Q22 and turns off switching element Q21, and then repeatedly turns off switching element Q22 and turns on switching element Q21. When the current detected by the current sensor Si21 is negative (when a current flows from the switching elements Q21 and Q22 to the input / output terminal T1 via the inductor L21), the control unit CNT keeps switching element Q23 always on and switching element Q24 always off, turns on switching element Q21 and turns off switching element Q22, and then repeatedly turns off switching element Q21 and turns on switching element Q22. As a result, when charging battery B, the AC power input from the commercial power supply to the bidirectional inverter circuit INV2 via the input / output terminals T1 and T2 is power factor corrected and rectified, and the rectified power is smoothed by capacitor C2 and output to the bidirectional DC-DC converter circuit CNV2.

[0045] <Example of operation control of bidirectional inverter circuit INV1 when power is supplied from a single-phase three-wire system> The control unit CNT turns on the switching elements Q11 and Q14 and turns off the switching elements Q12 and Q13, and then repeatedly turns off the switching elements Q11 and Q14 and turns on the switching elements Q12 and Q13. As a result, the DC power input from the bidirectional DC-DC converter circuit CNV1 to the bidirectional inverter circuit INV1 via the capacitor C1 is converted into AC power by the bidirectional inverter circuit INV1 and supplied to the load Loα connected between the input / output terminal T1 and the neutral terminal Tn.

[0046] Note that there may be a switching element that turns on and off only during polarity reversal. For example, during a period when input / output terminal T1 is at a positive voltage, switching element Q14 may be always on, switching elements Q12 and Q13 may be always off, and switching element Q11 may be turned on and off repeatedly, and during a period when input / output terminal T1 is at a negative voltage, switching element Q13 may be always on, switching elements Q11 and Q14 may be always off, and switching element Q12 may be turned on and off repeatedly.

[0047] <Example of operation control of bidirectional inverter circuit INV2 when power is supplied from a single-phase three-wire system> The control unit CNT turns on switching elements Q21 and Q24 and turns off switching elements Q22 and Q23, and then repeatedly turns off switching elements Q21 and Q24 and turns on switching elements Q22 and Q23. As a result, the DC power input from the bidirectional DC-DC converter circuit CNV2 to the bidirectional inverter circuit INV2 via capacitor C2 is converted into AC power by the bidirectional inverter circuit INV2 and supplied to the load Loβ connected between the input / output terminal T2 and the neutral terminal Tn.

[0048] Note that there may be a switching element that turns on and off only during polarity reversal. For example, during a period when neutral terminal Tn is at a positive voltage, switching element Q24 may be always on, switching elements Q22 and Q23 may be always off, and switching element Q21 may be turned on and off repeatedly, and during a period when neutral terminal Tn is at a negative voltage, switching element Q23 may be always on, switching elements Q21 and Q24 may be always off, and switching element Q22 may be turned on and off repeatedly.

[0049] 2 is a diagram showing a circuit example of the bidirectional DC-DC converter circuit CNV1. Note that the circuit example of the bidirectional DC-DC converter circuit CNV2 may be the same as the bidirectional DC-DC converter circuit CNV1 shown in FIG.

[0050] 2 includes a transformer Tr, switching elements Q1 to Q4 that form a bridge circuit on the primary side of the transformer Tr, switching elements Q5 to Q8 that form a bridge circuit on the secondary side of the transformer Tr, and a capacitor C. The switching elements Q1 to Q8 are configured, for example, by MOSFETs.

[0051] The drain terminals of switching elements Q1 and Q3 are connected to one end of capacitor C1, and the source terminals of switching elements Q2 and Q4 are connected to the other end of capacitor C1. The junction between the source terminal of switching element Q1 and the drain terminal of switching element Q2 is connected to one end of a primary coil Lt1 of transformer Tr, and the junction between the source terminal of switching element Q3 and the drain terminal of switching element Q4 is connected to the other end of the primary coil Lt1. The drain terminals of switching elements Q5 and Q7 are connected to one end of capacitor C and the positive terminal of battery B, and the source terminals of switching elements Q6 and Q8 are connected to the other end of capacitor C and the negative terminal of battery B. The junction between the source terminal of switching element Q5 and the drain terminal of switching element Q6 is connected to one end of a secondary coil Lt2 of transformer Tr, and the junction between the source terminal of switching element Q7 and the drain terminal of switching element Q8 is connected to the other end of the secondary coil Lt2.

[0052] Note that the circuit example of the bidirectional DC-DC converter circuit CNV1 is not limited to the example shown in Fig. 2, as long as it can convert the DC power output from the bidirectional inverter circuit INV1 into a predetermined DC power and supply it to the battery B when charging the battery B, and can convert the DC power output from the battery B into a predetermined DC power and supply it to the bidirectional inverter circuit INV1 when supplying power in a single-phase three-wire system. The same applies to the bidirectional DC-DC converter circuit CNV2.

[0053] <Example of operation control of bidirectional DC-DC converter circuit CNV1 when charging battery B> The control unit CNT turns on the switching elements Q1 and Q4 and turns off the switching elements Q2 and Q3 so that the power output to the battery B follows the target power Pt1, and then repeatedly turns off the switching elements Q1 and Q4 and turns on the switching elements Q2 and Q3, thereby generating an AC current in the primary coil Lt1 and synchronously rectifying it with the switching elements Q5 to Q8. Note that the target power Pt1 is set based on, for example, the voltage of the battery B.

[0054] <Example of operation control of bidirectional DC-DC converter circuit CNV1 when power is supplied via a single-phase three-wire system> The control unit CNT turns on the switching elements Q6 and Q7 and turns off the switching elements Q5 and Q8 so that the power output to the bidirectional inverter circuit INV1 follows the target power Pt2, and then repeatedly turns off the switching elements Q6 and Q7 and turns on the switching elements Q5 and Q8, thereby generating an AC current in the secondary coil Lt2 and synchronously rectifying it with the switching elements Q1 to Q4. Note that the target power Pt2 is set based on, for example, the voltages of the capacitors C1 and C2.

[0055] When the bidirectional DC-DC converter circuit CNV1 is driven using the DAB (Dual Active Bridge) method, the duty ratio of the drive signals that drive the switching elements Q1 to Q8 may each be set to 50% and the phases of the drive signals for the switching elements Q1 to Q4 and the phases of the drive signals for the switching elements Q5 to Q8 may be shifted from each other depending on the target power Pt1 or the target power Pt2.

[0056] Furthermore, an example of the operation control of the bidirectional DC-DC converter circuit CNV2 when the battery B is being charged or when power is being supplied in a single-phase three-wire system may be the same as the example of the operation control of the bidirectional DC-DC converter circuit CNV1 when the battery B is being charged or when power is being supplied in a single-phase three-wire system.

[0057] In this way, the bidirectional charger Ch of the embodiment can reduce noise input to the commercial power supply side when charging the battery B. This can simplify, for example, noise reduction filters (not shown) provided in the bidirectional inverter circuits INV1 and INV2.

[0058] Furthermore, according to the bidirectional charger Ch of the embodiment, since it is configured to include the bidirectional power conversion circuits PC1 and PC2, it is possible to increase the total power supplied between the input / output terminal T1 and the input / output terminal T2 compared to a configuration including only one bidirectional power conversion circuit.

[0059] Furthermore, with the bidirectional charger Ch of the embodiment, when power is supplied via a single-phase three-wire system, the power supply between the input / output terminal T1 and the neutral terminal Tn is handled by capacitor C1, and the power supply between the input / output terminal T2 and the neutral terminal Tn is handled by capacitor C2. Because power is supplied from two independent capacitors, the system has good controllability and is resistant to disturbances.

[0060] Furthermore, according to the bidirectional charger Ch of the embodiment, when, for example, one CPU is used as the control unit CNT to control the two bidirectional inverter circuits INV1 and INV2, the direction of current is the same in the bidirectional inverter circuit INV1 and the bidirectional inverter circuit INV2, making it easy to control with the control unit CNT.

[0061] Furthermore, according to the bidirectional charger Ch of the embodiment, when power is supplied via a single-phase three-wire system, the bidirectional inverter circuits INV1, INV2 are directly connected to each other at the neutral terminal Tn, but because this is via the connected inductor L21, current fluctuations can be suppressed by the inductor, and resonance is less likely to occur in the current loop via the stray capacitance of each of the bidirectional inverter circuits INV1, INV2.

[0062] The present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit and scope of the present invention.

[0063] <Variation 1> Fig. 3 is a diagram showing a first modified example of the bidirectional charger Ch of the embodiment. In Fig. 3, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0064] The bidirectional charger Ch shown in Fig. 3 differs from the bidirectional charger Ch shown in Fig. 1 in that a changeover switch SW1 is connected to an inductor L11. The changeover switch SW1 in Modification 1 connects the inductor L11 to the input / output terminal T2 when charging the battery B, and connects the inductor L11 to the neutral terminal Tn when supplying power in a single-phase three-wire system.

[0065] Furthermore, in Modification 1, the changeover switch SW2 is connected to the inductor L21, similar to the changeover switch SW2 shown in Fig. 1. That is, the changeover switch SW2 in Modification 1 connects the inductor L21 to the input / output terminal T1 when charging the battery B, and connects the inductor L21 to the neutral terminal Tn when supplying power in a single-phase three-wire system.

[0066] In addition, in variant 1, the connection point between the source terminal of switching element Q13 and the drain terminal of switching element Q14 is connected to input / output terminal T1, and the connection point between the source terminal of switching element Q23 and the drain terminal of switching element Q24 is connected to input / output terminal T2.

[0067] Therefore, in the bidirectional charger Ch shown in FIG. 3, similarly to the bidirectional charger Ch shown in FIG. 1, when charging the battery B, the bidirectional power conversion circuits PC1 and PC2 are connected between the input / output terminal T1 and the input / output terminal T2, respectively, and when supplying power in a single-phase three-wire system, the bidirectional power conversion circuit PC1 is connected between the input / output terminal T1 and the neutral terminal Tn, and the bidirectional power conversion circuit PC2 is connected between the input / output terminal T2 and the neutral terminal Tn.

[0068] That is, in the bidirectional charger Ch of variant 1, when charging the battery B, the inductor L11 is connected to the input / output terminal T2 and the inductor L21 is connected to the input / output terminal T1, and when supplying power in a single-phase three-wire system, the inductors L11 and L21 are each connected to the neutral terminal Tn.

[0069] As described above, in the bidirectional charger Ch shown in FIG. 3, like the bidirectional charger Ch shown in FIG. 1, each bidirectional inverter circuit INV included in the bidirectional power conversion circuits PC1 and PC2 is a totem-pole bidirectional inverter circuit INV, and the number of inductors L connected to the input / output terminals T1, T2, and neutral terminal Tn can be reduced, and the number of switching elements connected to the inductors L can also be reduced. This reduces the number of locations where fluctuations in the potential on the switching element side of the inductor L occur when the switching elements switch during power factor correction operation during charging. This reduces noise generated by switching of the switching element Q in the bidirectional inverter circuit INV when charging the battery B, and reduces noise input to the commercial power source when charging the battery B.

[0070] Furthermore, with the bidirectional charger Ch shown in FIG. 3, when power is supplied using a single-phase three-wire system, the bidirectional inverter circuits INV1, INV2 are directly connected to each other at the neutral terminal Tn. However, because the inductors L11, L12 are connected therebetween, current fluctuations can be suppressed by the inductors, and resonance is less likely to occur in the current loop via the stray capacitance of each of the bidirectional inverter circuits INV1, INV2.

[0071] Furthermore, with the bidirectional charger Ch shown in Figure 3, when power is supplied via a single-phase three-wire system, the junction of switching elements Q11 and Q12 and the junction of switching elements Q21 and Q22 are connected via inductors L11 and L21, respectively, and are at the same potential as the neutral terminal Tn. The voltage at the junction of switching elements Q13 and Q14 relative to the neutral terminal Tn and the voltage at the junction of switching elements Q23 and Q24 relative to the neutral terminal Tn are opposite in phase and have the same potential difference. Dynamically, switching elements Q11 and Q21, Q12 and Q22 connected to inductors L11 and L22 operate in opposite phase and synchronized fashion, while switching elements Q13 and Q23, and Q14 and Q24 not connected to inductors operate in opposite phase and synchronized fashion. If the bidirectional inverter circuits INV1 and INV2 have approximately the same structure, the stray capacitances of each component are approximately equal. This means that the voltage of the ground path, through which common-mode noise flows, is approximately equal to the neutral terminal Tn. This suppresses the generation of common-mode noise currents and reduces noise.

[0072] <Variation 2> Fig. 4 is a diagram showing a second modified example of the bidirectional charger Ch of the embodiment. In Fig. 4, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0073] The bidirectional charger Ch shown in Fig. 4 differs from the bidirectional charger Ch shown in Fig. 1 in that changeover switch SW2 is connected to the junction between the source terminal of switching element Q23 and the drain terminal of switching element Q24. Changeover switch SW2 in modification 2 connects the junction between the source terminal of switching element Q23 and the drain terminal of switching element Q24 to input / output terminal T1 when charging battery B, and connects the junction between the source terminal of switching element Q23 and the drain terminal of switching element Q24 to neutral terminal Tn when supplying single-phase three-wire power.

[0074] In addition, in Modification 2, selector switch SW1 is connected to the connection point between the source terminal of switching element Q13 and the drain terminal of switching element Q14, similar to selector switch SW1 shown in Fig. 1. That is, selector switch SW1 in Modification 2 connects the connection point between the source terminal of switching element Q13 and the drain terminal of switching element Q14 to input / output terminal T2 when charging battery B, and connects the connection point between the source terminal of switching element Q13 and the drain terminal of switching element Q14 to neutral terminal Tn when supplying power in a single-phase three-wire system.

[0075] In the second modification, the inductor L11 is connected to the input / output terminal T1, and the inductor L21 is connected to the input / output terminal T2.

[0076] Therefore, in the bidirectional charger Ch shown in FIG. 4, similarly to the bidirectional charger Ch shown in FIG. 1, when charging the battery B, the bidirectional power conversion circuits PC1 and PC2 are connected between the input / output terminal T1 and the input / output terminal T2, respectively, and when supplying power in a single-phase three-wire system, the bidirectional power conversion circuit PC1 is connected between the input / output terminal T1 and the neutral terminal Tn, and the bidirectional power conversion circuit PC2 is connected between the input / output terminal T2 and the neutral terminal Tn.

[0077] That is, in the bidirectional charger Ch of the second modification, whether the battery B is being charged or a single-phase three-wire power supply is being performed, the inductor L11 is connected to the input / output terminal T1 and the inductor L21 is connected to the input / output terminal T2.

[0078] As described above, in the bidirectional charger Ch shown in FIG. 4, like the bidirectional charger Ch shown in FIG. 1, each bidirectional inverter circuit INV included in the bidirectional power conversion circuits PC1 and PC2 is a totem-pole bidirectional inverter circuit INV, and the number of inductors L connected to the input / output terminals T1, T2, and neutral terminal Tn can be reduced, and the number of switching elements connected to the inductors L can also be reduced. This reduces the number of locations where fluctuations in the potential on the switching element side of the inductor L occur when the switching elements are switched during power factor correction operation during charging. This reduces noise generated by switching of the switching element Q in the bidirectional inverter circuit INV when charging the battery B, and reduces noise input to the commercial power source when charging the battery B.

[0079] Furthermore, with the bidirectional charger Ch shown in Figure 4, when power is supplied via a single-phase, three-wire system, the junction of switching elements Q13 and Q14 and the junction of switching elements Q23 and Q24 are at the same potential as the neutral terminal Tn. The voltage at the junction of switching elements Q11 and Q12 relative to the neutral terminal Tn and the voltage at the junction of switching elements Q21 and Q22 relative to the neutral terminal Tn are opposite in phase and have the same potential difference. Dynamically, switching elements Q11 and Q21, and Q12 and Q22 connected to inductors L11 and L22 operate in opposite phases, while switching elements Q13 and Q23, and Q14 and Q24 not connected to an inductor operate in opposite phases. If the bidirectional inverter circuits INV1 and INV2 have approximately the same structure, the stray capacitances of each component are approximately equal. Therefore, the voltage of the ground path, through which common-mode noise flows, is approximately equal to the neutral terminal Tn. This suppresses the generation of common-mode noise currents and reduces noise.

[0080] <Variation 3> Fig. 5 is a diagram showing a third modified example of the bidirectional charger Ch of the embodiment. In Fig. 5, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0081] The bidirectional charger Ch shown in FIG. 5 differs from the bidirectional charger Ch shown in FIG. 1 in that the bidirectional inverter circuits INV1 and INV2 are each configured as an interleaved bidirectional inverter circuit INV.

[0082] The bidirectional inverter circuit INV1 in Modification 3 is a totem-pole bidirectional inverter circuit having inductors in only two of its three arms, and includes inductor L11, inductor L12 (third coil), switching elements Q11-Q14, switching element Q15 (ninth switching element), switching element Q16 (tenth switching element), capacitor C1, voltage sensors Sv11 and Sv12, and current sensors Si11 and Si12. Current sensor Si12 detects the current flowing through inductor L12 when battery B is being charged or when single-phase three-wire power is being supplied, and sends the detected current to control unit CNT. Switching elements Q15 and Q16 form a fifth arm.

[0083] One end of inductor L11 is connected to input / output terminal T1 and one end of inductor L12, and the other end of inductor L11 is connected to the connection point between the source terminal of switching element Q11 and the drain terminal of switching element Q12. The other end of inductor L12 is connected to the connection point between the source terminal of switching element Q15 and the drain terminal of switching element Q16. The connection point between the source terminal of switching element Q13 and the drain terminal of switching element Q14 is connected to input / output terminal T2 and neutral terminal Tn via selector switch SW1. The drain terminals of switching elements Q11, Q13, and Q15 are connected to each other and to one end of capacitor C1. The source terminals of switching elements Q12, Q14, and Q16 are connected to each other and to the other end of capacitor C1.

[0084] The bidirectional inverter circuit INV2 in Modification 3 is a totem-pole bidirectional inverter circuit with inductors in only two of its three arms, and includes inductor L21, inductor L22 (fourth coil), switching elements Q21-Q24, switching element Q25 (eleventh switching element), switching element Q26 (twelfth switching element), capacitor C2, voltage sensors Sv21 and Sv22, and current sensors Si21 and Si22. Current sensor Si22 detects the current flowing through inductor L22 when battery B is being charged or when single-phase three-wire power is being supplied, and sends the detected current to control unit CNT. Switching elements Q25 and Q26 form a sixth arm.

[0085] One end of inductor L21 is connected to input / output terminal T1 and neutral terminal Tn via selector switch SW2, and is also connected to one end of inductor L22. The other end of inductor L21 is connected to the junction between the source terminal of switching element Q21 and the drain terminal of switching element Q22. The other end of inductor L22 is connected to the junction between the source terminal of switching element Q25 and the drain terminal of switching element Q26. The junction between the source terminal of switching element Q23 and the drain terminal of switching element Q24 is connected to input / output terminal T2. The drain terminals of switching elements Q21, Q23, and Q25 are connected to each other and to one end of capacitor C2. The source terminals of switching elements Q22, Q24, and Q26 are connected to each other and to the other end of capacitor C2.

[0086] <Example of operation control of bidirectional inverter circuit INV1 when charging battery B> When the current detected by the current sensors Si11 and Si12 is positive (when current flows from the commercial power supply to the switching elements Q11, Q12, Q15, and Q16 via the inductors L11 and L12), the control unit CNT keeps the switching element Q14 always on and the switching element Q13 always off, turns on the switching elements Q12 and Q15 and turns off the switching elements Q11 and Q16, and then repeatedly turns off the switching elements Q12 and Q15 and turns on the switching elements Q11 and Q16. Furthermore, when the current detected by the current sensors Si11 and Si12 is negative (when current flows from switching elements Q11, Q12, Q15, and Q16 to the commercial power supply via inductors L11 and L12), the control unit CNT keeps switching element Q13 always on and switching element Q14 always off, turns on switching elements Q11 and Q16 and turns off switching elements Q12 and Q15, and then repeatedly turns off switching elements Q11 and Q16 and turns on switching elements Q12 and Q15. In other words, the power factor correction operation by inductor L11 and switching elements Q11, Q12, Q13, and Q14 and the power factor correction operation by inductor L12 and switching elements Q13, Q14, Q15, and Q16 operate with a phase shift. As a result, when charging battery B, the AC power input from the commercial power supply to the bidirectional inverter circuit INV1 via the input / output terminals T1 and T2 is power factor corrected and rectified, and the rectified power is smoothed by capacitor C1 and output to the bidirectional DC-DC converter circuit CNV1.

[0087] <Example of operation control of bidirectional inverter circuit INV2 when charging battery B> When the current detected by the current sensors Si21 and Si22 is positive (when current flows from the commercial power supply to the switching elements Q21, Q22, Q25, and Q26 via the inductors L21 and L22), the control unit CNT keeps the switching element Q24 always on and the switching element Q23 always off, turns on the switching elements Q22 and Q25 and turns off the switching elements Q21 and Q26, and then repeatedly turns off the switching elements Q22 and Q25 and turns on the switching elements Q21 and Q26. Furthermore, when the current detected by current sensors Si21 and Si22 is negative (when current flows from switching elements Q21, Q22, Q25, and Q26 to the commercial power supply via inductors L21 and L22), control unit CNT keeps switching element Q23 always on and switching element Q24 always off, turns on switching elements Q21 and Q26 and turns off switching elements Q22 and Q25, and then repeatedly turns off switching elements Q21 and Q26 and turns on switching elements Q22 and Q25. In other words, the power factor correction operation by inductor L21 and switching elements Q21, Q22, 23, and 24 and the power factor correction operation by inductor L22 and switching elements Q23, 24, 25, and 26 operate with a phase shift. As a result, when charging battery B, the AC power input from the commercial power supply to the bidirectional inverter circuit INV2 via the input / output terminals T1 and T2 is power factor corrected and rectified, and the rectified power is smoothed by capacitor C2 and output to the bidirectional DC-DC converter circuit CNV2.

[0088] <Example of operation control of bidirectional inverter circuit INV1 when power is supplied from a single-phase three-wire system> The control unit CNT keeps switching element Q14 always on, switching elements Q12, Q13, and Q16 always off, and repeatedly turns on and off switching elements Q11 and Q15 during a period when the input / output terminal T1 is at a positive voltage. During a period when the input / output terminal T1 is at a negative voltage, the control unit CNT keeps switching element Q13 always on, switching elements Q11, Q14, and Q15 always off, and repeatedly turns on and off switching elements Q12 and Q16. The arms of switching elements Q11 and Q12 may be configured to be out of phase with the arms of switching elements Q15 and Q16. This converts DC power input from the bidirectional DC-DC converter circuit CNV1 to the bidirectional inverter circuit INV1 via capacitor C1 into AC power, which is then supplied to a load Loα connected between the input / output terminal T1 and the neutral terminal Tn.

[0089] <Example of operation control of bidirectional inverter circuit INV2 when power is supplied from a single-phase three-wire system> During a period when the neutral terminal Tn is at a positive voltage, the control unit CNT keeps switching element Q24 always on, switching elements Q22, Q23, and Q26 always off, and repeatedly turns switching elements Q21 and Q25 on and off. During a period when the neutral terminal Tn is at a negative voltage, the control unit CNT keeps switching element Q23 always on, switching elements Q21, Q24, and Q25 always off, and repeatedly turns switching elements Q22 and Q26 on and off. The arms of switching elements Q21 and Q22 may be configured to be out of phase with the arms of switching elements Q25 and Q26. This converts DC power input from the bidirectional DC-DC converter circuit CNV2 to the bidirectional inverter circuit INV2 via capacitor C2 into AC power, which is then supplied to the load Loβ connected between the input / output terminal T2 and the neutral terminal Tn.

[0090] The interleaved bidirectional inverter circuits INV1 and INV2 may be applied to the bidirectional inverter circuits INV1 and INV2 shown in Fig. 3, or may be applied to the bidirectional inverter circuits INV1 and INV2 shown in Fig. 4. Furthermore, although the switching elements of the interleaved arms operate with a phase shift as described above, they may also be synchronized.

[0091] As described above, in the bidirectional charger Ch shown in FIG. 5, like the bidirectional charger Ch shown in FIG. 1, each bidirectional inverter circuit INV included in the bidirectional power conversion circuits PC1 and PC2 is a totem-pole bidirectional inverter circuit INV, and the number of inductors L connected to the input / output terminals T1, T2, and neutral terminal Tn can be reduced, and the number of switching elements connected to the inductors L can also be reduced. This reduces the number of locations where fluctuations in the potential on the switching element side of the inductor L occur when the switching elements are switched during power factor correction operation during charging. This reduces noise generated by switching of the switching element Q in the bidirectional inverter circuit INV when charging the battery B, and reduces noise input to the commercial power source when charging the battery B.

[0092] Furthermore, in the bidirectional charger Ch shown in FIG. 5, the bidirectional inverter circuits INV1 and INV2 are each an interleaved bidirectional inverter circuit INV, and therefore it is possible to increase the power supplied to the battery B when the battery B is being charged and the power supplied to the load Lo when power is supplied in a single-phase three-wire system.

[0093] Furthermore, according to the bidirectional charger Ch shown in FIG. 5, when, for example, one CPU is used as the control unit CNT to control the two bidirectional inverter circuits INV1 and INV2, the current flows in the same direction in the bidirectional inverter circuits INV1 and INV2, making it easy to control the control unit CNT.

[0094] Furthermore, in the bidirectional charger Ch shown in FIG. 5, the bidirectional inverter circuits INV1, INV2 are directly connected to each other at the neutral terminal Tn, but because the inductors L21, L22 are connected therebetween, current fluctuations can be suppressed by the inductors, and resonance is less likely to occur in the current loop via the stray capacitance of each of the bidirectional inverter circuits INV1, INV2.

[0095] Furthermore, according to the bidirectional charger Ch shown in FIG. 5, the amount of current flowing is distributed by interleaving an arm formed by switching elements Q11 and Q12 and an arm formed by switching elements Q15 and Q16, and by switching switching elements Q13 and Q14 only when polarity is reversed, the loss of each switching element can be leveled out compared to the embodiment and modified examples 1 and 2, and an increase in the number of switching elements can be suppressed. [Explanation of symbols]

[0096] Ch two-way charger SW1, SW2 selector switch PC1, PC2 Bidirectional power conversion circuit INV1, INV2 Bidirectional inverter circuit CNV1, CNV2 Bidirectional DC / DC converter circuit L11, L12, L21, L22 inductors Q11~Q16, Q21~Q26 switching elements C1 and C2 capacitors Sv11, Sv12, Sv21, Sv22 voltage sensors Si11, Si12, Si21, Si22 Current Sensors Loα, Loβ load B Battery T1, T2 input / output terminals Tn neutral terminal

Claims

1. a first input / output terminal connected to a first load; a second input / output terminal connected to a second load connected in series with the first load; a neutral terminal connected to a connection point between the first load and the second load and grounded; A first switch; A second switch; a first bidirectional inverter circuit connected to the first input / output terminal and one end of the first switch; a second bidirectional inverter circuit connected to the second input / output terminal and one end of the second switch; a first bidirectional DC-DC converter circuit that converts DC power supplied from the first bidirectional inverter circuit into DC power of a different voltage and outputs the converted DC power to a battery, and converts DC power supplied from the battery into DC power of a different voltage and outputs the converted DC power to the first bidirectional inverter circuit; a second bidirectional DC-DC converter circuit that converts DC power supplied from the second bidirectional inverter circuit into DC power of a different voltage and outputs the converted DC power to a battery, and converts DC power supplied from the battery into DC power of a different voltage and outputs the converted DC power to the second bidirectional inverter circuit; a control unit that controls the first bidirectional inverter circuit, the second bidirectional inverter circuit, the first bidirectional DC-DC converter circuit, the second bidirectional DC-DC converter circuit, the first switch, and the second switch; Equipped with the other end of the first switch is connected to be switchable between the neutral terminal and the second input / output terminal; the other end of the second switch is connected to be switchable between the neutral terminal and the first input / output terminal; The first bidirectional inverter circuit a first arm in which a first switching element and a second switching element are connected in series; a second arm in which a third switching element and a fourth switching element are connected in series; a first coil having one end connected to a connection point between the first switching element and the second switching element and the other end connected to either the first input / output terminal or one end of the first switch; Equipped with the first arm and the second arm are connected in parallel, and a connection point between the third switching element and the fourth switching element is connected to the other of the first input / output terminal and one end of the first switch, The second bidirectional inverter circuit a third arm in which a fifth switching element and a sixth switching element are connected in series; a fourth arm in which a seventh switching element and an eighth switching element are connected in series; a second coil having one end connected to a connection point between the fifth switching element and the sixth switching element and the other end connected to either the second input / output terminal or one end of the second switch; Equipped with The third arm and the fourth arm are connected in parallel, and a connection point between the seventh switching element and the eighth switching element is connected to the other of the second input / output terminal and one end of the second switch. A bidirectional charger characterized by:

2. 2. The bidirectional charger of claim 1, The control unit controls the bidirectional charger so that, when power is supplied via a single-phase three-wire system, the first coil of the first bidirectional inverter circuit is connected to the first input / output terminal and the second coil of the second bidirectional inverter circuit is connected to the neutral terminal.

3. 2. The bidirectional charger of claim 1, The control unit controls the bidirectional charger so that, when power is supplied via a single-phase three-wire system, the first coil of the first bidirectional inverter circuit is connected to the neutral terminal and the second coil of the second bidirectional inverter circuit is connected to the neutral terminal.

4. 2. The bidirectional charger of claim 1, The control unit controls the bidirectional charger so that, when power is supplied via a single-phase three-wire system, the first coil of the first bidirectional inverter circuit is connected to the first input / output terminal and the second coil of the second bidirectional inverter circuit is connected to the second input / output terminal.

5. The bidirectional charger according to any one of claims 1 to 4, the first bidirectional inverter circuit includes a fifth arm in which a ninth switching element and a tenth switching element are connected in series and which are connected in parallel to the first arm and the second arm, and a third coil; one end of the third coil is connected to a connection point between the ninth switching element and the tenth switching element, and the other end is connected to either the first input / output terminal or one end of the first switch; the second bidirectional inverter circuit has a sixth arm in which an eleventh switching element and a twelfth switching element are connected in series and which are connected in parallel to the third arm and the fourth arm, and a fourth coil; The fourth coil has one end connected to a connection point between the eleventh switching element and the twelfth switching element, and the other end connected to either the second input / output terminal or one end of the second switch. Two-way charger.

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