Bidirectional charger

Abstract

To provide a bidirectional charger capable of charging a battery or supplying power in a single-phase three-wire manner such that degradation of the performance of single-phase three-wire power supply during a single-phase connection time is suppressed.SOLUTION: A bidirectional charger Ch is formed by including: a bidirectional inverter circuit INV1 that is connected to input / output terminals T1, T2; a bidirectional inverter circuit INV2 that is connected to the input / output terminal T1 and a neutral terminal Tn; a bidirectional DCDC converter circuit CNV1 that outputs power from the bidirectional inverter circuit INV1 to a battery B and outputs power from the battery B to the bidirectional inverter circuit INV1; a bidirectional DCDC converter circuit CNV2 that outputs power from the bidirectional inverter circuit INV2 to the battery B and outputs power from the battery B to the bidirectional inverter circuit INV2; and a control unit CNT that controls the bidirectional inverter circuits INV1, INV2 and the bidirectional DCDC converter circuits CNV1, CNV2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] There is a bidirectional charger that, when charging a battery, converts AC power supplied from a commercial power source into DC power using a bidirectional inverter circuit, converts the DC power into a predetermined DC power using a bidirectional DCDC converter circuit, and outputs it to the battery, and when supplying power using a single-phase two-wire system, converts DC power supplied from the battery into a predetermined DC power using a bidirectional DCDC converter circuit, and converts the predetermined DC power into AC power using a bidirectional inverter circuit, and outputs it to a load. Related technology is disclosed in Patent Document 1.

[0003] However, although Patent Document 1 discloses power supply to a three-phase load as shown in FIG. 5, it does not clearly describe a method for power supply to a single-phase three-wire load. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-164539 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of one aspect of the present invention is to address imbalances in load power consumption when supplying single-phase three-wire power in a bidirectional charger capable of charging a battery or supplying single-phase three-wire power. [Means for solving the problem]

[0006] a first bidirectional inverter circuit connected to the first input / output terminals and the second input / output terminals; a second bidirectional inverter circuit connected to the first input / output terminals and the neutral terminal; 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 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 DC-DC 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 control unit that controls the first bidirectional inverter circuit, the second bidirectional inverter circuit, the first bidirectional DC-DC converter circuit, and the second bidirectional DC-DC converter circuit.

[0007] Thus, by simultaneously controlling the first bidirectional inverter circuit, the second bidirectional inverter circuit, the first bidirectional DC-DC converter circuit, and the second bidirectional DC-DC converter circuit, when the power consumed by the first load is greater than the power consumed by the second load, the power obtained by subtracting the power consumed by the second load from the power consumed by the first load can be supplied to the first load via the second bidirectional DC-DC converter and the second bidirectional inverter circuit.Furthermore, when the power consumed by the second load is greater than the power consumed by the first load, the power obtained by subtracting the power consumed by the first load from the power consumed by the second load can be regenerated to the battery via the second bidirectional inverter circuit and the second bidirectional DC-DC converter circuit.

[0008] Also, a bidirectional charger according to one aspect 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 bidirectional inverter circuit connected to the first input / output terminal and the second input / output terminal, a second bidirectional inverter circuit connected to the first input / output terminal, a switch having one end connected to the second bidirectional inverter circuit and the other end capable of switching between being connected to the neutral terminal or the second input / output terminal, and a converter for converting DC power supplied from the first bidirectional inverter circuit into DC power of a different voltage. a first bidirectional DCDC converter circuit that 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 control unit that controls the first bidirectional inverter circuit, the second bidirectional inverter circuit, the first bidirectional DCDC converter circuit, and the second bidirectional DCDC converter circuit.

[0009] As a result, when an external AC power supply is connected to the first input / output terminal and the second input / output terminal and the other end of the switch is connected to the second input / output terminal, DC power can be supplied to the battery via the first bidirectional inverter circuit and the first bidirectional DC-DC converter circuit, and also via the second bidirectional inverter circuit and the second bidirectional DC-DC converter circuit.

[0010] 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, a third arm in which a fifth switching element and a sixth 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 the first input / output terminal, and a second coil having one end connected to a connection point between the third switching element and the fourth switching element and the other end connected to the first input / output terminal, and the first arm, the second arm, and the third arm are connected in parallel, and the connection point between the fifth switching element and the sixth switching element is connected to the second input / output terminal, The direction inverter circuit may include a fourth arm in which a seventh switching element and an eighth switching element are connected in series, a fifth arm in which a ninth switching element and a tenth switching element are connected in series, a sixth arm in which an eleventh switching element and a twelfth switching element are connected in series, a third coil having one end connected to a connection point between the seventh switching element and the eighth switching element and the other end connected to the first input / output terminal, and a fourth coil having one end connected to a connection point between the ninth switching element and the tenth switching element and the other end connected to the first input / output terminal, wherein the fourth arm, the fifth arm, and the sixth arm are connected in parallel, and the connection point between the eleventh switching element and the twelfth switching element is connected to the neutral terminal.

[0011] As a result, by increasing the number of arms of the first bidirectional inverter circuit, single-phase three-wire output can be achieved even for the first bidirectional inverter circuit in which the first and second arms are interleaved and the second bidirectional inverter circuit in which the fourth and fifth arms are interleaved, thereby suppressing degradation of the element performance.

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

[0013] As a result, by increasing the number of arms of the first bidirectional inverter circuit, single-phase three-wire output can be achieved even for a first bidirectional inverter circuit in which the first and second arms are interleaved, and a second bidirectional inverter circuit in which the fourth and fifth arms are interleaved. [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 deal with imbalances in power consumption of loads when supplying single-phase three-wire power. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a diagram illustrating an example of a bidirectional charger according to the first embodiment. [Figure 2] FIG. 1 is a diagram illustrating an example of a bidirectional DC-DC converter circuit. [Figure 3] 5 is a flowchart showing the operation of a control unit when power is supplied in a single-phase three-wire system in the first embodiment. [Figure 4] FIG. 10 is a diagram illustrating an example of a bidirectional charger according to a second embodiment. [Figure 5] 10 is a flowchart showing the operation of a control unit when power is supplied in a single-phase three-wire system in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0017] First Embodiment FIG. 1 is a diagram illustrating an example of a bidirectional charger according to the first 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] It is assumed that when the battery B is being charged, power is supplied to the bidirectional charger Ch from a commercial power supply (external AC power supply) not shown.

[0020] 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 electrical appliances that operate on AC 100V. The current consumptions of the loads Loα and Loβ are 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 are cases where the power consumption α and power consumption β are the same value, cases where power consumption α is greater than power consumption β, and cases where power consumption β is greater than power consumption α. ​​Furthermore, when power is supplied using a single-phase three-wire system, the voltage applied between input / output terminal T1 and neutral terminal Tn and the voltage applied between input / output terminal T2 and neutral terminal Tn are controlled to be equal to AC 100V. When there is no distinction between load Loα and Loβ, they are simply referred to as load Lo.

[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 includes a current sensor Si1, a current sensor Si2, a switch SW, 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. Note that the bidirectional power conversion circuit PC1 is always connected between the input / output terminal T1 and the input / output terminal T2.

[0023] Further, the current sensor Si1 detects the current flowing through the input / output terminal T1, and sends the detected current to the control unit CNT, which will be described later.

[0024] Further, the current sensor Si2 detects the current flowing through the input / output terminal T2 and sends the detected current to the control unit CNT, which will be described later.

[0025] When battery B is being charged, switch SW connects bidirectional power conversion circuit PC2 between input / output terminal T1 and input / output terminal T2. When battery B is being charged, a commercial power supply is connected between input / output terminal T1 and input / output terminal T2. Therefore, when battery B is being charged, power can be supplied from the commercial power supply to battery B via bidirectional power conversion circuit PC1 and bidirectional power conversion circuit 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.

[0026] Furthermore, the switch SW connects the bidirectional power conversion circuit PC2 between the input / output terminal T1 and the neutral terminal Tn when single-phase three-wire power is supplied. Therefore, when single-phase three-wire power is supplied, the bidirectional power conversion circuit PC1 is connected between the input / output terminal T1 and the input / output terminal T2, and the bidirectional power conversion circuit PC2 is connected between the input / output terminal T1 and the neutral terminal Tn.

[0027] <Example of operation of bidirectional power conversion circuits PC1 and PC2 when charging battery B> When charging the battery B, the bidirectional power conversion circuits PC1 and PC2 convert AC power supplied from a commercial power source via the input / output terminals T1 and T2 into DC power and output it to the battery B, respectively.

[0028] <Example of operation of bidirectional power conversion circuits PC1 and PC2 when supplying power through a single-phase three-wire system> The bidirectional power conversion circuit PC1 is controlled so that 200V AC is applied between input / output terminals T1 and T2, and the bidirectional power conversion circuit PC2 is controlled so that 100V AC is applied between input / output terminals T1 and neutral terminal Tn. As mentioned above, loads Loα and Loβ are devices that operate at 100V AC, and their respective current consumptions are Iα and Iβ. Therefore, when current consumption Iα flows through load Loα at 100V AC, this is the power consumption α, and when current consumption Iβ flows through load Loβ at 100V AC, this is the power consumption β.

[0029] When a load Loα is connected only between the input / output terminal T1 and the neutral terminal Tn, the bidirectional power conversion circuit PC2 controls the DC power supplied from the battery B so that a consumption current Iα flows at AC 100V. In other words, the bidirectional power conversion circuit PC2 converts the DC power supplied from the battery B into AC power equivalent to the power consumption α of the load Loα and outputs that AC power between the input / output terminal T1 and the neutral terminal Tn. As a result, AC power equivalent to the power consumption α is supplied between the input / output terminal T1 and the neutral terminal Tn, allowing the load Loα to be driven. Note that although the bidirectional power conversion circuit PC1 generates AC 200V between the input / output terminal T1 and the input / output terminal T2, no current flows.

[0030] When a load Loβ is connected only between the input / output terminal T2 and the neutral terminal Tn, the bidirectional power conversion circuit PC2 regenerates the surplus output power of the bidirectional power conversion circuit PC1 that is not consumed by the load Loβ to the battery B. Specifically, the bidirectional power conversion circuit PC1 controls the DC power supplied from the battery B to flow a consumption current Iβ at AC 200V. As a result, the bidirectional power conversion circuit PC1 converts the DC power supplied from the battery B into AC power equivalent to twice the power consumption β of the load Loβ and outputs the AC power between the input / output terminal T1 and the input / output terminal T2. As a result, AC power equivalent to the consumption current Iβ, i.e., the power consumption β, at AC 100V is supplied between the input / output terminal T2 and the neutral terminal Tn, thereby driving the load Loβ. Note that the bidirectional power conversion circuit PC2 regenerates AC power equivalent to the consumption current Iβ, i.e., the power consumption β, at AC 100V between the input / output terminal T1 and the neutral terminal Tn, to the battery B, from the AC power output from the bidirectional power conversion circuit PC1.

[0031] When a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn, and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and when the power consumption α of the load Loα and the power consumption β of the load Loβ are the same, the bidirectional power conversion circuit PC1 controls the DC power supplied from the battery B to flow a consumption current Iα (=Iβ) at AC 200V. As a result, the bidirectional power conversion circuit PC1 converts the DC power supplied from the battery B into AC power equivalent to twice the power consumption α or twice the power consumption β, and outputs the AC power between the input / output terminal T1 and the input / output terminal T2. As a result, the consumption current Iα (=Iβ) at AC 100V is supplied between the input / output terminal T1 and the neutral terminal Tn, and between the input / output terminal T2 and the neutral terminal Tn, i.e., AC power equivalent to the power consumption α or the power consumption β, respectively, so that the load Loα and the load Loβ can be driven simultaneously.

[0032] When a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn, and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and when the power consumption α of the load Loα is greater than the power consumption β of the load Loβ, the bidirectional power conversion circuit PC2 supplies the insufficient output power of the bidirectional power conversion circuit PC1 to the load Loα from the battery B. Specifically, the bidirectional power conversion circuit PC1 controls the DC power supplied from the battery B to flow a consumption current Iβ at AC 200V. As a result, the bidirectional power conversion circuit PC1 converts the DC power supplied from the battery B to AC power equivalent to twice the power consumption β and outputs this AC power between the input / output terminal T1 and the input / output terminal T2. The bidirectional power conversion circuit PC2 also controls the DC power supplied from the battery B to flow a current obtained by subtracting the consumption current Iβ from the consumption current Iα at AC 100V. In other words, the bidirectional power conversion circuit PC2 converts the DC power supplied from the battery B to AC power equivalent to the power consumption obtained by subtracting the power consumption β from the power consumption α and outputs this AC power between the input / output terminal T1 and the neutral terminal Tn. As a result, AC power equivalent to the power consumption α is supplied between the input / output terminal T1 and the neutral terminal Tn, and AC power equivalent to the power consumption β is supplied between the input / output terminal T2 and the neutral terminal Tn, so that the load Loα and the load Loβ can be driven simultaneously.

[0033] When a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn, and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and when the power consumption β of the load Loβ is greater than the power consumption α of the load Loα, the bidirectional power conversion circuit PC2 regenerates the surplus output power of the bidirectional power conversion circuit PC1 that is not consumed by the load Loβ to the battery B. Specifically, the bidirectional power conversion circuit PC1 controls the DC power supplied from the battery B to flow a consumption current Iβ at AC 200V. As a result, the bidirectional power conversion circuit PC1 converts the DC power into AC power equivalent to twice the power consumption β and outputs the AC power between the input / output terminal T1 and the input / output terminal T2. The bidirectional power conversion circuit PC2 also controls the AC power output from the bidirectional power conversion circuit PC1 to be regenerated to the battery B between the input / output terminal T1 and the neutral terminal Tn at AC 100V, the current obtained by subtracting the consumption current Iα from the consumption current Iβ. That is, of the AC power output from the bidirectional power conversion circuit PC1, AC power equivalent to the power consumption obtained by subtracting the power consumption α from the power consumption β is converted into DC power, and this DC power is regenerated to the battery B. As a result, AC power equivalent to the power consumption α is supplied between the input / output terminal T1 and the neutral terminal Tn, and AC power equivalent to the power consumption β is supplied between the input / output terminal T2 and the neutral terminal Tn, so that the load Loα and the load Loβ can be driven simultaneously.

[0034] In this way, when the power consumption α of the load Loα and the power consumption β of the load Loβ are different from each other, the imbalance in the power consumption of the load Loα and the load Loβ can be addressed by adjusting the power output from the bidirectional power conversion circuit PC1 between the input / output terminal T1 and the input / output terminal T2 and adjusting the power output from the bidirectional power conversion circuit PC2 between the input / output terminal T1 and the neutral terminal Tn or the power input to the bidirectional power conversion circuit PC2 from between the input / output terminal T1 and the neutral terminal Tn. In other words, when the power consumption α is greater than the power consumption β or when the power consumption β is greater than the power consumption α, the excess or deficiency of the power supplied to the load Loα by the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2 can be adjusted.

[0035] By using such a circuit configuration and control, single-phase charging and single-phase three-wire power supply can be performed while maintaining the interleaved connection.

[0036] <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).

[0037] <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 a commercial power source into DC power and outputs it to the bidirectional DCDC converter circuit CNV1, and the bidirectional DCDC converter circuit CNV1 converts DC power supplied from the bidirectional inverter circuit INV1 into DC power of a different voltage and outputs it to battery B.

[0038] Furthermore, when charging battery B, the bidirectional inverter circuit INV2 converts the AC power supplied from the commercial power source into DC power and outputs it to the bidirectional DCDC converter circuit CNV2, and the bidirectional DCDC converter circuit CNV2 converts the DC power supplied from the bidirectional inverter circuit INV2 into DC power of a different voltage and outputs it to battery B.

[0039] <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 PC2 controls the AC voltage between the input / output terminal T1 and the neutral terminal Tn to be the AC voltage Vac, and the bidirectional power conversion circuit PC1 controls the AC voltage between the input / output terminal T1 and the input / output terminal T2 to be the AC voltage Vac', which is twice the AC voltage Vac. The loads Loα and Loβ are devices that operate on the AC voltage Vac, and their respective current consumptions are Iα and Iβ. Therefore, the power consumption of the load Loα when the consumption current Iα flows through the load Loα at the AC voltage Vac is α, and the power consumption of the load Loβ when the consumption current Iβ flows through the load Loβ at the AC voltage Vac is β.

[0040] During single-phase three-wire power supply, when a load Loα is connected only between the input / output terminal T1 and the neutral terminal Tn, the bidirectional DC-DC converter circuit CNV2 converts the DC power supplied from the battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV2. The bidirectional inverter circuit INV2 then converts the DC power output from the bidirectional DC-DC converter circuit CNV2 into AC power of AC voltage Vac x current consumption Iα and outputs it between the input / output terminal T1 and the neutral terminal Tn. In other words, the bidirectional inverter circuit INV2 outputs AC power equivalent to the power consumption α of the load Loα between the input / output terminal T1 and the neutral terminal Tn. As a result, the power consumption α is supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, allowing the load Loα to be driven.

[0041] For example, it is assumed that the AC voltage Vac is AC 100V, the current consumption Iα is AC 50A, and the power consumption α is AC 100V×AC 50A=5kVA.

[0042] In this case, when power is supplied via a single-phase three-wire system, the bidirectional inverter circuit INV2 outputs AC 100V x AC 50A = 5kVA between the input / output terminal T1 and the neutral terminal Tn. This allows 5kVA AC power to be supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, driving the load Loα.

[0043] 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 inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2 regenerate to the battery B the surplus (excess) power output from the bidirectional inverter circuit INV1 between the input / output terminals T1 and T2 that is not consumed by the load Loβ. Specifically, the bidirectional DC-DC converter circuit CNV1 converts the DC power supplied from the battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV1. The bidirectional inverter circuit INV1 then converts the DC power output from the bidirectional DC-DC converter circuit CNV1 into AC power of AC voltage Vac' × current consumption Iβ and outputs it between the input / output terminals T and T2. In other words, the bidirectional inverter circuit INV1 outputs AC power equivalent to twice the power consumption β between the input / output terminals T1 and T2. As a result, the power consumption β is supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing the load Loβ to be driven. Furthermore, the bidirectional inverter circuit INV2 converts AC power equivalent to AC voltage Vac x consumption current Iβ, out of the power output from the bidirectional inverter circuit INV1 between the input / output terminal T1 and the neutral terminal Tn, 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 a predetermined DC power and regenerates it to the battery B. This allows surplus power to be regenerated to the battery B during single-phase three-wire power supply, thereby preventing a decrease in the power consumption of the battery B.

[0044] For example, it is assumed that the AC voltage Vac' is AC 200V, the current consumption Iβ is AC 40A, and the power consumption β is AC 100V×AC 40A=4kVA.

[0045] In this case, when power is supplied via a single-phase three-wire system, the bidirectional inverter circuit INV1 outputs AC 200V x AC 40A = 8kVA AC power between the input / output terminals T1 and T2. As a result, AC power of 4kVA is supplied to the load Loβ from between the input / output terminal T1 and the neutral terminal Tn, enabling the load Loβ to be driven.

[0046] Furthermore, during single-phase three-wire power supply, when a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and when the power consumption α of the load Loα and the power consumption β of the load Loβ are the same, the bidirectional DC-DC converter circuit CNV1 converts the DC power supplied from the battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV1. The bidirectional inverter circuit INV1 then converts the DC power output from the bidirectional DC-DC converter circuit CNV1 into AC power of AC voltage Vac′ × consumption current Iα or AC power of AC voltage Vac′ × consumption current Iβ and outputs it between the input / output terminals T1 and T2. In other words, the bidirectional inverter circuit INV1 outputs AC power equivalent to twice the power consumption α or β between the input / output terminals T1 and T2. As a result, power consumption α is supplied to load Loα from between input / output terminal T1 and neutral terminal Tn, and power consumption β is supplied to load Loβ from between input / output terminal T2 and neutral terminal Tn, so that load Loα and load Loβ can be driven simultaneously.

[0047] For example, it is assumed that the AC voltage Vac' is AC 200V, the current consumption Iα and current consumption Iβ are AC 50A, and the power consumption α of the load Loα and the power consumption β of the load Loβ are AC 100V×AC 50A=5kVA.

[0048] In this case, when power is supplied through a single-phase three-wire system, the bidirectional inverter circuit INV1 outputs AC 200V × AC 50A = 10kVA AC power between the input / output terminals T1 and T2. As a result, 5kVA AC power is supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, and 5kVA AC power is supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing the loads Loα and Loβ to be driven simultaneously.

[0049] Furthermore, during single-phase three-wire power supply, if a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and if the power consumption α of the load Loα is greater than the power consumption β of the load Loβ, the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2 compensate for the shortfall in the output power of the bidirectional inverter circuit INV1 from the power consumption α of the load Loα. Specifically, the bidirectional DC-DC converter circuit CNV1 converts 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 then converts the DC power output from the bidirectional DC-DC converter circuit CNV1 into AC power of AC voltage Vac' × current consumption Iβ and outputs it between the input / output terminals T1 and T2. In other words, the bidirectional inverter circuit INV1 outputs AC power equivalent to twice the power consumption β of the load Loβ between the input / output terminals T1 and T2. Furthermore, 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 converts the DC power output from the bidirectional DC-DC converter circuit CNV2 into AC power equivalent to AC voltage Vac × (current obtained by subtracting current consumption Iβ from current consumption Iα), and outputs this AC power between the input / output terminal T1 and the neutral terminal Tn. That is, the bidirectional inverter circuit INV2 outputs power equivalent to the power consumption obtained by subtracting power consumption β from power consumption α between the input / output terminal T1 and the neutral terminal Tn. As a result, power consumption α is supplied to load Loα from between the input / output terminal T1 and the neutral terminal Tn, and power consumption β is supplied to load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing load Loα and load Loβ to be driven simultaneously.

[0050] For example, assume that the AC voltage Vac is AC100V, the AC voltage Vac' is AC200V, the current consumption Iα is AC50A, the current consumption Iβ is AC40A, the power consumption α of the load Loα is AC100V×AC50A=5kVA, and the power consumption β of the load Loβ is AC100V×AC40A=4kVA.

[0051] In this case, when power is supplied via a single-phase three-wire system, the bidirectional inverter circuit INV1 outputs 8 kVA AC power (200 V AC × 40 A AC) between the input / output terminals T1 and T2, and the bidirectional inverter circuit INV2 outputs 1 kVA AC power (100 V AC × (50 A AC - 40 A AC)) between the input / output terminal T1 and the neutral terminal Tn. This allows 5 kVA AC power to be supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, and 4 kVA AC power to be supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing the loads Loα and Loβ to be driven simultaneously.

[0052] Furthermore, during single-phase three-wire power supply, if a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and if the power consumption β of the load Loβ is greater than the power consumption α of the load Loα, the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2 regenerate to the battery B the surplus (excess) power not consumed by the load Loα out of the power output from the bidirectional inverter circuit INV1 between the input / output terminals T1 and T2. Specifically, the bidirectional DC-DC converter circuit CNV1 converts the DC power supplied from the battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV1, and the bidirectional inverter circuit INV1 converts the DC power output from the bidirectional DC-DC converter circuit CNV1 into AC power of AC voltage Vac′ × consumption current Iβ and outputs it between the input / output terminals T1 and T2. That is, the bidirectional inverter circuit INV1 outputs AC power equivalent to twice the power consumption β of the load Loβ between the input / output terminals T1 and T2. The bidirectional inverter circuit INV2 converts the surplus AC power output from the bidirectional inverter circuit INV1 between the input / output terminal T1 and the neutral terminal Tn, that is, AC voltage Vac × (current consumption Iβ - current consumption Iα), into DC power and outputs it to the bidirectional DC-DC converter circuit CNV2. The bidirectional DC-DC converter circuit CNV2 converts the DC power output from the bidirectional inverter circuit INV2 into a predetermined DC power and regenerates it in the battery B. That is, the bidirectional inverter circuit INV2 outputs AC power equivalent to the power consumption obtained by subtracting the power consumption α from the power consumption β out of the AC power output from the bidirectional inverter circuit INV1 between the input / output terminal T1 and the neutral terminal Tn to the bidirectional DC-DC converter circuit CNV2. As a result, power consumption α is supplied to load Loα from between input / output terminal T1 and neutral terminal Tn, and power consumption β is supplied to load Loβ from between input / output terminal T2 and neutral terminal Tn, so that load Loα and load Loβ can be driven simultaneously.

[0053] For example, assume that the AC voltage Vac is AC100V, the AC voltage Vac' is AC200V, the current consumption Iα is AC40A, the current consumption Iβ is AC50A, the power consumption α of the load Loα is AC100V×AC40A=4kVA, and the power consumption β of the load Loβ is AC100V×AC50A=5kVA.

[0054] In this case, when power is supplied via a single-phase, three-wire system, the bidirectional inverter circuit INV1 outputs 10 kVA of AC power (200 V AC × 50 A AC) between the input / output terminals T1 and T2, and the bidirectional inverter circuit INV2 converts 1 kVA of AC power (100 V AC × (50 A AC - 40 A AC)) out of the 5 kVA of power output from the bidirectional inverter circuit INV1 between the input / output terminal T1 and the neutral terminal Tn into DC power and outputs it to the bidirectional DC-DC converter circuit CNV2. As a result, 4 kVA of AC power is supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, and 5 kVA of AC power is supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing the loads Loα and Loβ to be driven simultaneously.

[0055] <Configuration of bidirectional inverter circuit INV1> The bidirectional inverter circuit INV1 is an interleaved totem-pole bridgeless PFC (Power Factor Circuit) and includes a coil L11 (first coil), a coil L12 (second 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 switching element Q15 (fifth switching element), a switching element Q16 (sixth switching element), a capacitor C1, voltage sensors Sv11 and Sv12, and current sensors Si11 and Si12. The bidirectional inverter circuit INV1 includes an arm AR1 (first arm) in which switching elements Q11 and Q12 are connected in series, an arm AR2 (second arm) in which switching elements Q13 and Q14 are connected in series, and an arm AR3 (third arm) in which switching elements Q15 and Q16 are connected in series. For example, the switching elements Q11 to Q16 are configured by MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). One terminal of coil L11 is connected to one terminal of coil L12 and input / output terminal T1, and the other terminal of coil L11 is connected to the junction between the source terminal of switching element Q11 and the drain terminal of switching element Q12. The other terminal of coil L12 is connected to the junction between the source terminal of switching element Q13 and the drain terminal of switching element Q14. The junction between the source terminal of switching element Q15 and the drain terminal of switching element Q16 is connected to input / output terminal T2. The drain terminals of switching elements Q11, Q13, and Q15 are connected to each other and to one terminal of capacitor C1. The source terminals of switching elements Q12, Q14, and Q16 are connected to each other and to the other terminal of capacitor C1. That is, one end of coil L11 is connected to the junction between switching element Q11 and switching element Q12, and the other end is connected to input / output terminal T1. One end of coil L11 may be connected to the junction between switching element Q11 and switching element Q12 via a wire or directly. One end of coil L12 is connected to the connection point between switching element Q13 and switching element Q14, and the other end is connected to input / output terminal T1. Note that one end of coil L12 may be connected to the connection point between switching element Q13 and switching element Q14 via a wire or may be connected directly.

[0056] 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 or when single-phase three-wire power is being supplied, and sends the detected voltage to the control unit CNT.

[0057] 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.

[0058] The current sensor Si11 detects the current flowing through the coil 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.

[0059] The current sensor Si12 detects the current flowing through the coil L12 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.

[0060] <Configuration of bidirectional inverter circuit INV2> Like the bidirectional inverter circuit INV1, the bidirectional inverter circuit INV2 is an interleaved totem-pole bridgeless PFC and includes a coil L21 (third coil), a coil L22 (fourth coil), a switching element Q21 (seventh switching element), a switching element Q22 (eighth switching element), a switching element Q23 (ninth switching element), a switching element Q24 (tenth switching element), a switching element Q25 (eleventh switching element), a switching element Q26 (twelfth switching element), a capacitor C2, voltage sensors Sv21 and Sv22, and current sensors Si21 and Si22. For example, the switching elements Q21 to Q26 are configured by MOSFETs. The bidirectional inverter circuit INV2 includes an arm AR4 (fourth arm) in which switching elements Q21 and Q22 are connected in series, an arm AR5 (fifth arm) in which switching elements Q23 and Q24 are connected in series, and an arm AR6 (sixth arm) in which switching elements Q25 and Q26 are connected in series. When coils L11, L12, L21, and L22 are not distinguished, they are simply referred to as coil L. The bidirectional inverter circuits INV1 and INV2 are not limited to totem-pole bridgeless PFCs. For example, the bidirectional inverter circuits INV1 and INV2 may be interleaved non-totem-pole bridgeless PFCs.

[0061] One terminal of coil L21 is connected to one terminal of coil L22 and input / output terminal T1, and the other terminal of coil L21 is connected to the junction between the source terminal of switching element Q21 and the drain terminal of switching element Q22. The other terminal of coil L22 is connected to the junction between the source terminal of switching element Q23 and the drain terminal of switching element Q24. The junction between the source terminal of switching element Q25 and the drain terminal of switching element Q26 is connected to input / output terminal T2 and neutral terminal Tn via switch SW. The drain terminals of switching elements Q21, Q23, and Q25 are connected to each other and to one terminal of capacitor C2. The source terminals of switching elements Q22, Q24, and Q26 are connected to each other and to the other terminal of capacitor C2. That is, one end of coil L21 is connected to the junction between switching element Q21 and switching element Q22, and the other end is connected to input / output terminal T1. One end of coil L21 may be connected directly or via a wire to the junction between switching element Q21 and switching element Q22. One end of coil L22 is connected to the junction between switching element Q23 and switching element Q24, and the other end is connected to input / output terminal T1. One end of coil L22 may be connected directly or via a wire to the junction between switching element Q23 and switching element Q24. Switch SW has one end connected to bidirectional inverter circuit INV2 and the other end selectable between neutral terminal Tn and input / output terminal T2. One end of switch SW may be connected directly or via a wire to bidirectional inverter circuit INV2. The other end of switch SW may be connected directly or via a wire to neutral terminal Tn or input / output terminal T2.

[0062] 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 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.

[0063] 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.

[0064] The current sensor Si21 detects the current flowing through the coil 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.

[0065] The current sensor Si22 detects the current flowing through the coil L22 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.

[0066] As described above, the bidirectional inverter circuits INV1 and INV2 are interleaved bidirectional inverter circuits. Therefore, when power is supplied from a single-phase, three-wire system, the current flowing through each of the two arms including coils L11 and L12 can be sent to the load Loα, and the current flowing through each of the two arms including coils L21 and L22 can be sent to the load Loβ. This allows for more power to be supplied to the loads Loα and Loβ than when the bidirectional inverter circuits INV1 and INV2 are not interleaved, i.e., when the current flowing through one arm is sent to the load Loα and the current flowing through the other arm is sent to the load Loβ. Furthermore, by increasing the number of arms in the bidirectional inverter circuit INV1, single-phase, three-wire output is possible even for the bidirectional inverter circuit INV1 in which arms AR1 and AR2 are interleaved, and the bidirectional inverter circuit INV2 in which arms AR4 and AR5 are interleaved.

[0067] <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 operation of the switch SW 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 operation of the switch SW, 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.

[0068] <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 to Q14 via the coils L11 and L12), the control unit CNT keeps the switching element Q16 always on and the switching element Q15 always off, turns on the switching elements Q12 and Q13 and turns off the switching elements Q11 and Q14, and then repeatedly turns off the switching elements Q12 and Q13 and turns on the switching elements Q11 and Q14. Furthermore, when the current detected by the current sensors Si11 and Si12 is negative (when current flows from switching elements Q11 to Q14 to the commercial power supply via coils L11 and L12), the control unit CNT keeps switching element Q15 always on and switching element Q16 always off, turns on switching elements Q12 and Q13 and turns off switching elements Q11 and Q14, and then repeatedly turns off switching elements Q12 and Q13 and turns on switching elements Q11 and Q14. In other words, the power factor correction operation by coil L11 and switching elements Q11, Q12, Q15, and Q16 and the power factor correction operation by coil L12 and switching elements Q15, Q16, Q13, and Q14 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.

[0069] <Example of operation control of bidirectional inverter circuit INV2 when charging battery B or when supplying power (regenerative) using a single-phase three-wire system> When the current detected by the current sensors Si21 and Si22 is positive (when a current flows from the commercial power supply or the bidirectional inverter circuit INV1 to the switching elements Q21 to Q24 via the coils L11 and L12), the control unit CNT keeps the switching element Q26 always on and the switching element Q25 always off, turns on the switching elements Q22 and Q23 and turns off the switching elements Q21 and Q24, and then repeatedly turns off the switching elements Q22 and Q23 and turns on the switching elements Q21 and Q24. Furthermore, when the current detected by current sensors Si21 and Si22 is negative (when current flows from switching elements Q21-Q24 to the commercial power supply or bidirectional inverter circuit INV1 via coils L21 and L22), control unit CNT keeps switching element Q25 always on and switching element Q26 always off, turns on switching elements Q22 and Q23 and turns off switching elements Q21 and Q24, and then repeatedly turns off switching elements Q22 and Q23 and turns on switching elements Q21 and Q24. In other words, the power factor correction operation by coil L21 and switching elements Q21, Q22, Q25, and Q6 and the power factor correction operation by coil L22 and switching elements Q25, Q26, Q23, and Q24 operate with a phase shift. As a result, when battery B is being charged or when single-phase three-wire power is being supplied, the AC power input to the bidirectional inverter circuit INV2 from the commercial power supply or between the input / output terminal T1 and the neutral terminal Tn is rectified while having its power factor corrected, and the rectified power is smoothed by capacitor C2 and output to the bidirectional DC-DC converter circuit CNV2.

[0070] <Example of operation control of bidirectional inverter circuit INV1 when power is supplied via a single-phase three-wire system> When the polarity of the AC current flowing from the bidirectional inverter circuit INV1 to the load Lo is positive (when current flows from the switching elements Q11 to Q14 to the coils L11 and L12), the control unit CNT keeps the switching element Q16 always on and the switching element Q15 always off, turns on the switching elements Q11 and Q13 and turns off the switching elements Q12 and Q14, and then repeatedly turns off the switching elements Q11 and Q13 and turns on the switching elements Q12 and Q14. Furthermore, when the polarity of the AC current flowing from the bidirectional inverter circuit INV1 to the load Lo is negative (when current flows from coils L11 and L12 to switching elements Q11 to Q14), the control unit CNT keeps switching element Q15 always on and switching element Q16 always off, turns on switching elements Q12 and Q14 and turns off switching elements Q11 and Q13, and then turns off switching elements Q12 and Q14 and turns on switching elements Q11 and Q13, repeatedly. As a result, the DC power input from the bidirectional DC-DC converter circuit CNV1 to the bidirectional inverter circuit INV1 via capacitor C1 is converted into AC power by the bidirectional inverter circuit INV1 and supplied to the load Lo.

[0071] <Example of operation control of bidirectional inverter circuit INV2 when supplying power to a single-phase three-wire system (when supplying power to a load Loα)> When the polarity of the AC current flowing from the bidirectional inverter circuit INV2 to the load Lo is positive (when current flows from switching elements Q21 to Q24 to coils L21 and L22), the control unit CNT keeps switching element Q26 always on and switching element Q25 always off, turns on switching elements Q21 and Q23 and turns off switching elements Q22 and Q24, and then repeatedly turns off switching elements Q21 and Q23 and turns on switching elements Q22 and Q24. Furthermore, when the polarity of the AC current flowing from the bidirectional inverter circuit INV2 to the load Lo is negative (when current flows from coils L21 and L22 to switching elements Q21 to Q24), the control unit CNT keeps switching element Q25 always on and switching element Q26 always off, turns on switching elements Q22 and Q24 and turns off switching elements Q21 and Q23, and then turns off switching elements Q22 and Q24 and turns on switching elements Q21 and Q23, repeatedly. As a result, the DC power input to the bidirectional inverter circuit INV2 from the bidirectional DC-DC converter circuit CNV2 via capacitor C2 is converted into AC power by the bidirectional inverter circuit INV2 and supplied to the load Lo.

[0072] 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.

[0073] 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.

[0074] The drain terminals of switching elements Q1 and Q3 are connected to one terminal of capacitor C1, and the source terminals of switching elements Q2 and Q4 are connected to the other terminal 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 terminal 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 terminal of the primary coil Lt1. The drain terminals of switching elements Q5 and Q7 are connected to one terminal 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 terminal 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 terminal 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 terminal of the secondary coil Lt2.

[0075] 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 supplied from the battery B into DC power of a different voltage 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.

[0076] <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.

[0077] <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 voltage of the capacitor C1.

[0078] 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.

[0079] 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.

[0080] 3 is a flowchart showing an example of the operation of the control unit CNT during single-phase three-wire power supply in the first embodiment. The bidirectional power conversion circuit PC2 controls the AC voltage between the input / output terminal T1 and the neutral terminal Tn to be the AC voltage Vac, and the bidirectional power conversion circuit PC1 controls the AC voltage between the input / output terminal T1 and the input / output terminal T2 to be the AC voltage Vac', which is twice the AC voltage Vac. The loads Loα and Loβ are devices that operate on the AC voltage Vac, and their respective consumption currents are Iα and Iβ. Therefore, the power consumption of the load Loα when the consumption current Iα flows through the load Loα at the AC voltage Vac is defined as α, and the power consumption of the load Loβ when the consumption current Iβ flows through the load Loβ at the AC voltage Vac is defined as β.

[0081] First, upon receiving a command to start single-phase three-wire power supply from a user or the like (step S1: Yes), the control unit CNT starts controlling the operation of the switch SW and the bidirectional power conversion circuits PC1 and PC2 and determines whether loads Loα and Loβ are connected to the input / output terminals T1 and T2 (step S2). For example, the control unit CNT may determine whether loads Loα and Loβ are connected to the input / output terminals T1 and T2 based on the currents detected by the current sensors Si1 and Si2 when a predetermined AC power (e.g., AC power not exceeding the rated power of the loads Loα and Loβ) is output from the bidirectional inverter circuit INV1 between the input / output terminals T1 and T2. Furthermore, for example, after determining that the load Loα is connected to the input / output terminal T1, the control unit CNT may calculate the power consumption α of the load Loα based on the AC current detected by the current sensor Si1. Furthermore, for example, after determining that the load Loβ is connected to the input / output terminal T2, the control unit CNT may calculate the power consumption β of the load Loβ based on the AC current detected by the current sensor Si2.

[0082] Next, when the control unit CNT determines that the load Loα is connected only between the input / output terminal T1 and the neutral terminal Tn (step S2: No, step S3: Yes), it controls the operation of the bidirectional power conversion circuit PC2 so that power equivalent to AC voltage Vac×current consumption Iα is output from the battery B between the input / output terminal T1 and the neutral terminal Tn via the bidirectional power conversion circuit PC2 (step S4), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the power consumption α to the load Loα.

[0083] Furthermore, if the control unit CNT determines that the load Loβ is connected only between the input / output terminal T2 and the neutral terminal Tn (step S2: No, step S3: No), it controls the operation of the bidirectional power conversion circuits PC1 and PC2 so that power equivalent to AC voltage Vac' x current consumption Iβ is output from the battery B between the input / output terminal T1 and the input / output terminal T2 via the bidirectional power conversion circuit PC1, and power equivalent to AC voltage Vac x current consumption Iβ is regenerated between the input / output terminal T1 and the neutral terminal Tn to the battery B via the bidirectional power conversion circuit PC2 (step S6), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the power consumption β to the load Loβ. Note that it is not necessary to regenerate power to the battery B between the input / output terminal T1 and the neutral terminal Tn via the bidirectional power conversion circuit PC2.

[0084] Furthermore, if the control unit CNT determines that the loads Loα and Loβ are connected to the input / output terminals T1 and T2 (step S2: Yes) and that the power consumption α and the power consumption β are the same (step S7: Yes), it controls the operation of the bidirectional power conversion circuit PC1 so that power equivalent to the AC voltage Vac′×the current consumption Iα or the current consumption Iβ is output from the battery B between the input / output terminals T1 and T2 via the bidirectional power conversion circuit PC1 (step S8), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the power consumption α or the power consumption β to the loads Loα and Loβ, respectively.

[0085] Furthermore, if the control unit CNT determines that the loads Loα and Loβ are connected to the input / output terminals T1 and T2 (step S2: Yes) and if the power consumption α is greater than the power consumption β (step S7: No, step S9: Yes), it controls the operation of the bidirectional power conversion circuits PC1 and PC2 so that power equivalent to AC voltage Vac′ × current consumption Iβ is output from battery B between input / output terminals T1 and T2 via the bidirectional power conversion circuit PC1, and power equivalent to AC voltage Vac × “current consumption Iα − current consumption Iβ” is output from battery B between input / output terminal T1 and neutral terminal Tn via the bidirectional power conversion circuit PC2 (step S10), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the power consumption α to the load Loα, and the bidirectional charger Ch to supply the power consumption β to the load Loβ.

[0086] Furthermore, if the control unit CNT determines that the loads Loα and Loβ are connected to the input / output terminals T1 and T2 (step S2: Yes) and if the power consumption β is greater than the power consumption α (step S7: No, step S9: No), it controls the operation of the bidirectional power conversion circuits PC1 and PC2 so that power equivalent to AC voltage Vac′ × current consumption Iβ is output from battery B between input / output terminals T1 and T2 via the bidirectional power conversion circuit PC1, and power equivalent to AC voltage Vac × “current consumption Iβ − current consumption Iα” is regenerated between input / output terminal T1 and neutral terminal Tn to battery B via the bidirectional power conversion circuit PC2 (step S11), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the power consumption α to the load Loα, and the bidirectional charger Ch to supply the power consumption β to the load Loβ.

[0087] Furthermore, when an instruction to terminate the single-phase three-wire power supply has not been input (step S5: No), the control unit CNT continues the single-phase three-wire power supply by repeating steps S2 to S11, and when an instruction to terminate the single-phase three-wire power supply is input (step S5: Yes), it stops controlling the operation of the bidirectional power conversion circuits PC1 and PC2 and terminates the single-phase three-wire power supply.

[0088] Second Embodiment Fig. 4 is a diagram showing an example of a bidirectional charger according to the second 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.

[0089] The bidirectional charger Ch shown in Fig. 4 differs from the bidirectional charger Ch shown in Fig. 1 in that, during single-phase three-wire power supply, the bidirectional power conversion circuit PC2 is connected between the input / output terminal T2 and the neutral terminal Tn by the switch SW'. Note that, during charging of the battery B, the bidirectional power conversion circuit PC2 is connected between the input / output terminal T1 and the input / output terminal T2 by the switch SW'.

[0090] That is, in the bidirectional charger Ch shown in FIG. 4, when single-phase three-wire power is supplied, a bidirectional power conversion circuit PC1 is connected between input / output terminal T1 and input / output terminal T2, and a bidirectional power conversion circuit PC2 is connected between input / output terminal T2 and neutral terminal Tn. Note that loads Loα and Loβ are electrical appliances that operate at 100V AC. The current consumptions of loads Loα and Loβ are Iα and Iβ, respectively. Therefore, when the current consumption Iα flows through load Loα at 100V AC, this is the power consumption α, and when the current consumption Iβ flows through load Loβ at 100V AC, 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 are cases where the power consumptions α and β are the same, where the power consumption α is greater than the power consumption β, and where the power consumption β is greater than the power consumption α. Furthermore, when power is supplied using a single-phase three-wire system, the voltage applied between the input / output terminal T1 and the neutral terminal Tn and the voltage applied between the input / output terminal T2 and the neutral terminal Tn are controlled to be equal to each other at 100V AC.

[0091] <Example of operation of bidirectional power conversion circuits PC1 and PC2 when supplying power through a single-phase three-wire system> The bidirectional power conversion circuit PC1 is controlled so that AC 200V is applied between the input / output terminal T1 and the input / output terminal T2, and the bidirectional power conversion circuit PC2 is controlled so that AC 100V is applied between the input / output terminal T2 and the neutral terminal Tn.

[0092] When a load Loα is connected only between the input / output terminal T1 and the neutral terminal Tn, the bidirectional power conversion circuit PC2 regenerates the surplus output power of the bidirectional power conversion circuit PC1 that is not consumed by the load Loα to the battery B. Specifically, the bidirectional power conversion circuit PC1 controls the DC power supplied from the battery B to flow a consumption current Iα at AC 200V. As a result, the bidirectional power conversion circuit PC1 converts the DC power supplied from the battery B into AC power equivalent to twice the power consumption α of the load Loα and outputs the AC power between the input / output terminal T1 and the input / output terminal T2. As a result, AC power equivalent to the consumption current Iα, i.e., the power consumption α, at AC 100V is supplied between the input / output terminal T1 and the neutral terminal Tn, thereby driving the load Loα. Note that the bidirectional power conversion circuit PC2 regenerates AC power equivalent to the consumption current Iα, i.e., the power consumption α, at AC 100V between the input / output terminal T2 and the neutral terminal Tn from the AC power output from the bidirectional power conversion circuit PC1 to the battery B.

[0093] When a load Loβ is connected only between the input / output terminal T2 and the neutral terminal Tn, the bidirectional power conversion circuit PC2 controls the DC power supplied from the battery B so that a consumption current Iβ flows at AC 100V. 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 between the input / output terminal T2 and the neutral terminal Tn. As a result, AC power equivalent to the power consumption β is supplied between the input / output terminal T2 and the neutral terminal Tn, so that the load Loβ can be driven.

[0094] When a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn, and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and when the power consumption α of the load Loα is greater than the power consumption β of the load Loβ, the bidirectional power conversion circuit PC2 regenerates the surplus output power of the bidirectional power conversion circuit PC1 that is not consumed by the load Loβ to the battery B. Specifically, the bidirectional power conversion circuit PC1 controls the DC power supplied from the battery B so that a consumption current Iα flows at AC 200V. As a result, the bidirectional power conversion circuit PC1 converts the DC power into AC power equivalent to twice the power consumption α and outputs the AC power between the input / output terminal T1 and the input / output terminal T2. The bidirectional power conversion circuit PC2 also controls the AC power output from the bidirectional power conversion circuit PC1 so that a current obtained by subtracting the consumption current Iβ from the consumption current Iα at AC 100V is regenerated to the battery B between the input / output terminal T2 and the neutral terminal Tn. That is, of the AC power output from the bidirectional power conversion circuit PC1, AC power equivalent to the power consumption obtained by subtracting the power consumption β from the power consumption α is converted into DC power, and this DC power is regenerated to the battery B. As a result, AC power equivalent to the power consumption α is supplied between the input / output terminal T1 and the neutral terminal Tn, and AC power equivalent to the power consumption β is supplied between the input / output terminal T2 and the neutral terminal Tn, so that the load Loα and the load Loβ can be driven simultaneously.

[0095] When a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn, and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and the power consumption β of the load Loβ is greater than the power consumption α of the load Loα, the bidirectional power conversion circuit PC2 supplies the insufficient power output from the bidirectional power conversion circuit PC1 to the load Loβ from the battery B. Specifically, the bidirectional power conversion circuit PC1 controls the DC power supplied from the battery B to flow a consumption current Iα at 200V AC. As a result, the bidirectional power conversion circuit PC1 converts the DC power supplied from the battery B to AC power equivalent to twice the power consumption α and outputs this AC power between the input / output terminal T1 and the input / output terminal T2. The bidirectional power conversion circuit PC2 also controls the DC power supplied from the battery B to flow a current obtained by subtracting the consumption current Iα from the consumption current Iβ at 100V AC. In other words, the bidirectional power conversion circuit PC2 converts the DC power supplied from the battery B to AC power equivalent to the power consumption obtained by subtracting the power consumption α from the power consumption β, and outputs this AC power between the input / output terminal T2 and the neutral terminal Tn. As a result, AC power equivalent to the power consumption α is supplied between the input / output terminal T1 and the neutral terminal Tn, and AC power equivalent to the power consumption β is supplied between the input / output terminal T2 and the neutral terminal Tn, so that the load Loα and the load Loβ can be driven simultaneously.

[0096] In this way, when the power consumption α of the load Loα and the power consumption β of the load Loβ are different from each other, the imbalance in the power consumption of the load Loα and the load Loβ can be addressed by adjusting the power output from the bidirectional power conversion circuit PC1 between the input / output terminal T1 and the input / output terminal T2, and by adjusting the power output from the bidirectional power conversion circuit PC2 between the input / output terminal T2 and the neutral terminal Tn, or the power input to the bidirectional power conversion circuit PC2 from between the input / output terminal T2 and the neutral terminal Tn. In other words, when the power consumption α is greater than the power consumption β, or when the power consumption β is greater than the power consumption α, the excess or deficiency of the power supplied to the load Loβ by the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2 can be adjusted.

[0097] By using such a circuit configuration and control, single-phase charging and single-phase three-wire power supply can be performed while maintaining the interleaved connection.

[0098] An example of operation of the bidirectional power conversion circuits PC1, PC2 when charging the battery B and an example of operation of the bidirectional power conversion circuits PC1, PC2 when the power consumption α of the load Loα and the power consumption β of the load Loβ are the same during single-phase three-wire power supply are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0099] <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 PC2 controls the AC voltage between the input / output terminal T2 and the neutral terminal Tn to be the AC voltage Vac, and the bidirectional power conversion circuit PC1 controls the AC voltage between the input / output terminal T1 and the input / output terminal T2 to be the AC voltage Vac', which is twice the AC voltage Vac. The loads Loα and Loβ are devices that operate on the AC voltage Vac, and their respective current consumptions are Iα and Iβ. Therefore, the power consumption of the load Loα when the consumption current Iα flows through the load Loα at the AC voltage Vac is α, and the power consumption of the load Loβ when the consumption current Iβ flows through the load Loβ at the AC voltage Vac is β.

[0100] During single-phase three-wire power supply, when a load Loα is connected only between the input / output terminal T1 and the neutral terminal Tn, the bidirectional DC-DC converter circuit CNV1 converts the DC power supplied from the battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV1. The bidirectional inverter circuit INV1 then converts the DC power output from the bidirectional DC-DC converter circuit CNV1 into AC power of AC voltage Vac' x current consumption Iα and outputs it between the input / output terminals T1 and T2. In other words, the bidirectional inverter circuit INV1 outputs AC power equivalent to twice the power consumption α between the input / output terminals T1 and T2. As a result, the power consumption α is supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, allowing the load Loα to be driven. Furthermore, the bidirectional inverter circuit INV2 converts AC power equivalent to AC voltage Vac x consumption current Iα, out of the power output from the bidirectional inverter circuit INV1 between the input / output terminal T2 and the neutral terminal Tn, 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 a predetermined DC power and regenerates it to the battery B. This allows surplus power to be regenerated to the battery B during single-phase three-wire power supply, thereby preventing a decrease in the power consumption of the battery B.

[0101] For example, it is assumed that the AC voltage Vac' is AC 200V, the current consumption Iα is AC 50A, and the power consumption α is AC 100V×AC 50A=5kVA.

[0102] In this case, when power is supplied via a single-phase three-wire system, the bidirectional inverter circuit INV1 outputs AC 200V x 50A x 2 = 10kVA AC power between the input / output terminals T1 and T2. This allows 5kVA AC power to be supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, driving the load Loα.

[0103] Furthermore, when power is supplied via a single-phase, three-wire system and a load Loβ is connected only between the input / output terminal T2 and the neutral terminal Tn, 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 then converts the DC power output from the bidirectional DC-DC converter circuit CNV2 into AC power of AC voltage Vac x current consumption Iβ and outputs it between the input / output terminal T2 and the neutral terminal Tn. In other words, the bidirectional inverter circuit INV2 outputs AC power equivalent to the power consumption β between the input / output terminal T2 and the neutral terminal Tn. This allows the power consumption β to be supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, thereby driving the load Loβ.

[0104] For example, it is assumed that the AC voltage Vac is AC 100V, the current consumption Iβ is AC 50A, and the power consumption β is AC 100V×AC 50A=5kVA.

[0105] In this case, when power is supplied via a single-phase three-wire system, the bidirectional inverter circuit INV2 outputs AC 100V x 50A = 5kVA AC power between the input / output terminal T2 and the neutral terminal Tn. This causes 5kVA AC power to be supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, enabling the load Loβ to be driven.

[0106] Furthermore, during single-phase three-wire power supply, if a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and if the power consumption α of the load Loα is greater than the power consumption β of the load Loβ, the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2 regenerate to the battery B the surplus (excess) power that is not consumed by the load Loβ out of the power output from the bidirectional inverter circuit INV1 between the input / output terminals T1 and T2. Specifically, the bidirectional inverter circuit INV1 converts the DC power supplied from the battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV1, and the bidirectional inverter circuit INV1 converts the DC power output from the bidirectional DC-DC converter circuit CNV1 into AC power of AC voltage Vac′ × consumption current Iα and outputs it between the input / output terminals T1 and T2. That is, the bidirectional inverter circuit INV1 outputs AC power equivalent to twice the power consumption α of the load Loα between the input / output terminals T1 and T2. The bidirectional inverter circuit INV2 converts the surplus AC power output from the bidirectional inverter circuit INV1 between the input / output terminal T2 and the neutral terminal Tn, that is, AC voltage Vac × (current consumption Iα − current consumption Iβ), into DC power and outputs it to the bidirectional DC-DC converter circuit CNV2. The bidirectional DC-DC converter circuit CNV2 converts the DC power output from the bidirectional inverter circuit INV2 into a predetermined DC power and regenerates it in the battery B. That is, the bidirectional inverter circuit INV2 outputs AC power equivalent to the power consumption obtained by subtracting the power consumption β from the power consumption α out of the AC power output from the bidirectional inverter circuit INV1 between the input / output terminal T2 and the neutral terminal Tn to the bidirectional DC-DC converter circuit CNV2. As a result, power consumption α is supplied to load Loα from between input / output terminal T1 and neutral terminal Tn, and power consumption β is supplied to load Loβ from between input / output terminal T2 and neutral terminal Tn, so that load Loα and load Loβ can be driven simultaneously.

[0107] For example, assume that the AC voltage Vac is AC100V, the AC voltage Vac' is AC200V, the current consumption Iα is AC50A, the current consumption Iβ is AC40A, the power consumption α of the load Loα is AC100V×AC50A=5kVA, and the power consumption β of the load Loβ is AC100V×AC40A=4kVA.

[0108] In this case, when power is supplied via a single-phase, three-wire system, the bidirectional inverter circuit INV1 outputs 10 kVA of AC power (200 V AC × 50 A AC) between the input / output terminals T1 and T2, and the bidirectional inverter circuit INV2 converts 1 kVA of AC power (100 V AC × (50 A AC - 40 A AC) = 1 kVA) from the 5 kVA power output from the bidirectional inverter circuit INV1 between the input / output terminal T2 and the neutral terminal Tn into DC power and outputs it to the bidirectional DC-DC converter circuit CNV2. As a result, 5 kVA of AC power is supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, and 4 kVA of AC power is supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing the loads Loα and Loβ to be driven simultaneously.

[0109] Furthermore, during single-phase three-wire power supply, if a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and if the power consumption β of the load Loβ is greater than the power consumption α of the load Loα, the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2 compensate for the shortfall in the output power of the bidirectional inverter circuit INV1 from the power consumption β of the load Loβ. Specifically, the bidirectional DC-DC converter circuit CNV1 converts DC power supplied from the battery B into DC power of a different voltage and outputs it to the bidirectional inverter circuit INV1. The bidirectional inverter circuit INV1 then converts the DC power output from the bidirectional DC-DC converter circuit CNV1 into AC power of AC voltage Vac' × current consumption Iα and outputs it between the input / output terminals T1 and T2. In other words, the bidirectional inverter circuit INV1 outputs AC power equivalent to twice the power consumption α of the load Loα between the input / output terminals T1 and T2. Furthermore, 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 converts the DC power output from the bidirectional DC-DC converter circuit CNV2 into AC power equivalent to AC voltage Vac × (current obtained by subtracting current consumption Iα from current consumption Iβ), and outputs this AC power between the input / output terminal T2 and the neutral terminal Tn. That is, the bidirectional inverter circuit INV2 outputs power equivalent to the power consumption obtained by subtracting power consumption α from power consumption β, between the input / output terminal T2 and the neutral terminal Tn. As a result, power consumption α is supplied to load Loα from between the input / output terminal T1 and the neutral terminal Tn, and power consumption β is supplied to load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing load Loα and load Loβ to be driven simultaneously.

[0110] For example, assume that the AC voltage Vac is AC 100V, the AC voltage Vac' is AC 200V, the current consumption Iα is AC 40A, the current consumption Iβ is AC 50A, the power consumption α of the load Loα is 4kVA, and the power consumption β of the load Loβ is 5kVA.

[0111] In this case, when power is supplied via a single-phase, three-wire system, the bidirectional inverter circuit INV1 outputs 8 kVA AC power (200 V AC × 40 A AC) between the input / output terminals T1 and T2, and the bidirectional inverter circuit INV2 outputs 1 kVA AC power (100 V AC × (50 A AC - 40 A AC)) between the input / output terminal T2 and the neutral terminal Tn. This allows 4 kVA AC power to be supplied to the load Loα from between the input / output terminal T1 and the neutral terminal Tn, and 5 kVA AC power to be supplied to the load Loβ from between the input / output terminal T2 and the neutral terminal Tn, allowing the loads Loα and Loβ to be driven simultaneously.

[0112] In addition, when a load Loα is connected between the input / output terminal T1 and the neutral terminal Tn and a load Loβ is connected between the input / output terminal T2 and the neutral terminal Tn, and when the power consumption α of the load Loα and the power consumption β of the load Loβ are the same, the operation example of the bidirectional inverter circuits INV1, INV2 and the bidirectional DC-DC converter circuits CNV1, CNV2 is the same as in the first embodiment, and therefore description thereof will be omitted.

[0113] FIG. 5 is a flowchart showing the operation of the control unit CNT during single-phase three-wire power supply in the second embodiment. Steps S1 to S3, S5, S7, and S9 shown in FIG. 5 are the same as steps S1 to S3, S5, S7, and S9 shown in FIG. 3 , and therefore will not be described again. The bidirectional power conversion circuit PC2 controls the AC voltage between the input / output terminal T2 and the neutral terminal Tn to be AC ​​voltage Vac, and the bidirectional power conversion circuit PC1 controls the AC voltage between the input / output terminal T1 and the input / output terminal T2 to be AC ​​voltage Vac', which is twice the AC voltage Vac. Loads Loα and Loβ are devices that operate on AC voltage Vac, and their respective current consumptions are Iα and Iβ. Therefore, the power consumption of the load Loα when the consumption current Iα flows through the load Loα at AC voltage Vac is defined as α, and the power consumption of the load Loβ when the consumption current Iβ flows through the load Loβ at AC voltage Vac is defined as β.

[0114] If the control unit CNT determines that the load Loα is connected only between the input / output terminal T1 and the neutral terminal Tn (step S2: No, step S3: Yes), it controls the operation of the bidirectional power conversion circuits PC1 and PC2 so that power equivalent to AC voltage Vac′×consumption current Iα is output from battery B between input / output terminal T1 and input / output terminal T2 via the bidirectional power conversion circuit PC1, and power equivalent to AC voltage Vac×consumption current Iα is regenerated between input / output terminal T2 and neutral terminal Tn to battery B via the bidirectional power conversion circuit PC2 (step S4′), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the consumed power α to the load Loα. Note that it is not necessary to regenerate power to battery B between the input / output terminal T2 and neutral terminal Tn via the bidirectional power conversion circuit PC2.

[0115] Furthermore, if the control unit CNT determines that the load Loβ is connected only between the input / output terminal T2 and the neutral terminal Tn (step S2: No, step S3: No), it controls the operation of the bidirectional power conversion circuit PC2 so that power equivalent to AC voltage Vac×current consumption Iβ is output from the battery B between the input / output terminal T2 and the neutral terminal Tn via the bidirectional power conversion circuit PC2 (step S6'), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the consumed power β to the load Loβ.

[0116] Furthermore, if the control unit CNT determines that the loads Loα and Loβ are connected to the input / output terminals T1 and T2 (step S2: Yes) and if the power consumption α is greater than the power consumption β (step S7: No, step S9: Yes), it controls the operation of the bidirectional power conversion circuits PC1 and PC2 so that power equivalent to AC voltage Vac′×consumption current Iα is output from battery B between input / output terminals T1 and T2 via the bidirectional power conversion circuit PC1, and power equivalent to AC voltage Vacדconsumption current Iα−consumption current Iβ” is regenerated between input / output terminal T2 and neutral terminal Tn via the bidirectional power conversion circuit PC2 to battery B (step S10′), and then proceeds to step S5. As a result, the power consumption α can be supplied from the bidirectional charger Ch to the load Loα, and the power consumption β can be supplied from the bidirectional charger Ch to the load Loβ.

[0117] Furthermore, if the control unit CNT determines that the loads Loα and Loβ are connected to the input / output terminals T1 and T2 (step S2: Yes) and if the power consumption β is greater than the power consumption α (step S7: No, step S9: No), it controls the operation of the bidirectional power conversion circuits PC1 and PC2 so that power equivalent to AC voltage Vac′×power consumption Iα is output from battery B between input / output terminals T1 and T2 via the bidirectional power conversion circuit PC1, and power equivalent to AC voltage Vacדpower consumption Iβ−power consumption Iα” is output from battery B between input / output terminal T2 and neutral terminal Tn via the bidirectional power conversion circuit PC2 (step S11′), and then proceeds to step S5. This allows the bidirectional charger Ch to supply the power consumption α to the load Loα, and the bidirectional charger Ch to supply the power consumption β to the load Loβ.

[0118] As described above, the bidirectional charger Ch of the first embodiment includes input / output terminals T1 and T2, a neutral terminal Tn, bidirectional inverter circuits INV1 and INV2, and bidirectional DC-DC converter circuits CNV1 and CNV2. By simultaneously controlling the bidirectional inverter circuits INV1 and INV2 and the bidirectional DC-DC converter circuits CNV1 and CNV2, when the power consumed by the load Loα is greater than the power consumed by the load Loβ, the power obtained by subtracting the power consumed by the load Loβ from the power consumed by the load Loα can be supplied to the load Loα via the bidirectional DC-DC converter circuit CNV2 and the bidirectional inverter circuit INV2. Furthermore, when the power consumed by the load Loβ is greater than the power consumed by the load Loα, the power obtained by subtracting the power consumed by the load Loα from the power consumed by the load Loβ can be regenerated to the battery B via the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2. In other words, the bidirectional charger Ch of the first embodiment can address the imbalance in power consumption of the load Lo when supplying power in a single-phase three-wire system.

[0119] The bidirectional charger Ch of the second embodiment includes input / output terminals T1 and T2, a neutral terminal Tn, bidirectional inverter circuits INV1 and INV2, and bidirectional DC-DC converter circuits CNV1 and CNV2. By simultaneously controlling the bidirectional inverter circuits INV1 and INV2 and the bidirectional DC-DC converter circuits CNV1 and CNV2, when the power consumed by the load Loα is greater than the power consumed by the load Loβ, the power obtained by subtracting the power consumed by the load Loβ from the power consumed by the load Loα can be regenerated to the battery B via the bidirectional DC-DC converter circuit CNV2 and the bidirectional inverter circuit INV2. When the power consumed by the load Loβ is greater than the power consumed by the load Loα, the power obtained by subtracting the power consumed by the load Loα from the power consumed by the load Loβ can be supplied to the load Loβ via the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2. In other words, the bidirectional charger Ch of the second embodiment can address the imbalance in power consumption of the load Lo when supplying power in a single-phase three-wire system.

[0120] Furthermore, the bidirectional charger Ch in the first and second embodiments is configured to include a switch SW. As a result, when a commercial power supply is connected to the input / output terminals T1 and T2 and the other end of the switch SW is connected to the input / output terminal T2 or the input / output terminal T1, DC power can be supplied to the battery B via the bidirectional inverter circuit INV1 and the bidirectional DC-DC converter circuit CNV1, and also via the bidirectional inverter circuit INV2 and the bidirectional DC-DC converter circuit CNV2.

[0121] In the bidirectional charger Ch of the first embodiment, the arms AR1, AR2, and AR3 are connected in parallel, and the connection point of the switching elements Q15 and Q16 is connected to the input / output terminal T2, and the arms AR4, AR5, and AR5 are connected in parallel, and the connection point of the switching elements Q25 and Q26 is connected to the neutral terminal Tn. This configuration allows for an increase in the number of arms in the bidirectional inverter circuit INV1, and therefore single-phase three-wire output is possible even for the bidirectional inverter circuit INV1 in which the arms AR1 and AR2 are interleaved, and the bidirectional inverter circuit INV2 in which the arms AR4 and AR5 are interleaved, thereby suppressing a decrease in the performance of the elements.

[0122] In the bidirectional charger Ch of the second embodiment, the arms AR1, AR2, and AR3 are connected in parallel, the connection point of the switching elements Q15 and Q16 is connected to the input / output terminal T2, and the arms AR4, AR5, and AR5 are connected in parallel, and the connection point of the coils L21 and L22 is connected to the neutral terminal Tn. This configuration allows for an increase in the number of arms in the bidirectional inverter circuit INV1, and therefore single-phase three-wire output is possible even for the bidirectional inverter circuit INV1 in which the arms AR1 and AR2 are interleaved, and the bidirectional inverter circuit INV2 in which the arms AR4 and AR5 are interleaved, thereby suppressing a decrease in the performance of the elements.

[0123] 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.

[0124] <Variation 1> In the first and second embodiments, one battery B is connected to the bidirectional power conversion circuits PC1 and PC2. However, a configuration in which battery B is connected to bidirectional power conversion circuit PC1 and a battery other than battery B is connected to bidirectional power conversion circuit PC2 may also be used. In such a configuration, when battery B and the other battery are being charged, power is supplied from the commercial power supply to battery B via the bidirectional power conversion circuit PC1, and power is supplied from the commercial power supply to the other battery via the bidirectional power conversion circuit PC2. Furthermore, during single-phase three-wire power supply, a state is established in which power can be supplied from battery B to the load Lo side via the bidirectional power conversion circuit PC1, and a state in which shortfalls in power can be supplied from the other battery to the load Lo side via the bidirectional power conversion circuit PC2 or surplus power can be regenerated in the other battery via the bidirectional power conversion circuit PC2.

[0125] <Variation 2> In the first and second embodiments, the bidirectional inverter circuits INV1 and INV2 are configured in an interleaved manner, but they do not have to be configured in an interleaved manner. For example, in the bidirectional inverter circuit INV1, the switching elements Q11 and Q12 and the arm AR1, or the switching elements Q13 and Q14 and the arm AR2, may be omitted. Also, in the bidirectional inverter circuit INV2, the switching elements Q21 and Q22 and the arm AR4, or the switching elements Q23 and Q24 and the arm AR5 may be omitted.

[0126] <Variation 3> In the first and second embodiments, the switch SW may be omitted. In this case, the connection point of the switching elements Q25 and Q26 in the first embodiment is directly connected to the neutral terminal Tn, and the connection point of the coils L21 and L22 in the second embodiment is directly connected to the neutral terminal Tn. [Explanation of symbols]

[0127] Ch two-way charger SW switch PC1, PC2 Bidirectional power conversion circuit INV1, INV2 Bidirectional inverter circuit CNV1, CNV2 Bidirectional DC / DC converter circuit L11, L12, L21, L22 coils 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 Si1, Si2 current sensors

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; and a first bidirectional inverter circuit connected to the first input / output terminal and the second input / output terminal; a second bidirectional inverter circuit connected to the first input / output terminal and the neutral terminal; 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 DC power to a battery, and also converts DC power supplied from the battery into DC power of a different voltage and outputs the 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 also 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, and the second bidirectional DC-DC converter circuit; Equipped with a bidirectional charger.

2. 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 bidirectional inverter circuit connected to the first input / output terminal and the second input / output terminal; a second bidirectional inverter circuit connected to the first input / output terminal; a switch having one end connected to the second bidirectional inverter circuit and the other end capable of switching between being connected to the neutral terminal or the second input / output terminal; 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 DC power to a battery, and also converts DC power supplied from the battery into DC power of a different voltage and outputs the 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 also 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, and the second bidirectional DC-DC converter circuit; Equipped with a bidirectional charger.

3. 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 third arm in which a fifth switching element and a sixth 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 the first input / output terminal; a second coil having one end connected to a connection point between the third switching element and the fourth switching element and the other end connected to the first input / output terminal, the first arm, the second arm, and the third arm are connected in parallel, and a connection point between the fifth switching element and the sixth switching element is connected to the second input / output terminal; the second bidirectional inverter circuit includes a fourth arm in which a seventh switching element and an eighth switching element are connected in series; a fifth arm in which a ninth switching element and a tenth switching element are connected in series; a sixth arm in which an eleventh switching element and a twelfth switching element are connected in series; a third coil having one end connected to a connection point between the seventh switching element and the eighth switching element and the other end connected to the first input / output terminal; a fourth coil having one end connected to a connection point between the ninth switching element and the tenth switching element and the other end connected to the first input / output terminal, The fourth arm, the fifth arm, and the sixth arm are connected in parallel, and the connection point between the eleventh switching element and the twelfth switching element is connected to the neutral terminal.

2. The bidirectional charger according to claim 1 .

4. 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 third arm in which a fifth switching element and a sixth 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 the first input / output terminal; a second coil having one end connected to a connection point between the third switching element and the fourth switching element and the other end connected to the first input / output terminal; Equipped with the first arm, the second arm, and the third arm are connected in parallel, and a connection point between the fifth switching element and the sixth switching element is connected to the second input / output terminal; The second bidirectional inverter circuit a fourth arm in which a seventh switching element and an eighth switching element are connected in series; a fifth arm in which a ninth switching element and a tenth switching element are connected in series; a sixth arm in which an eleventh switching element and a twelfth switching element are connected in series; a third coil having one end connected to a connection point between the seventh switching element and the eighth switching element and the other end connected to the first input / output terminal; a fourth coil having one end connected to a connection point between the ninth switching element and the tenth switching element and the other end connected to the first input / output terminal; Equipped with The fourth arm, the fifth arm, and the sixth arm are connected in parallel, and the connection point between the eleventh switching element and the twelfth switching element is connected to the one end of the switch.

3. The bidirectional charger according to claim 2.

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