Power system, power conversion device, control device, and control method

Abstract

Provided is a technology capable of effectively utilizing power of a distributed power supply at the time of power failure of a higher-level power system. A power system 1 according to an embodiment of the present disclosure comprises: a high-voltage battery 41 mounted on an electric vehicle 40; an inverter device 43 mounted on the electric vehicle 40 and electrically connected to the high-voltage battery 41; an electric load 21 provided in a home HM or a facility FC; a power supply unit 22 provided in the home HM or the facility FC and electrically connected to a power system 10 to supply power to the electric load 21; a power connection unit PC for electrically connecting between the power supply unit 22 and the electric vehicle 40; and a switch 23 for switching the electrical connection / disconnection between the power supply unit 22 and the power system 10. The switch 23 is switched to a disconnection state at the time of power failure of the power system 10. The inverter device 43 operates so as to function as a predetermined power supply for the power supply unit 22 using the power of the high-voltage battery 41 at the time of power failure of the power system 10.

Description

Power system, power converter, control device, control method

[0001] The present disclosure relates to a power system and the like.

[0002] For example, regarding distributed power sources, there is known a technology that stops power supply when islanding operation is detected due to a power outage of an upper-level power grid or the like (see Patent Document 1).

[0003] Japanese Unexamined Patent Application Publication No. 2015-107032

[0004] However, if power supply is stopped during a power outage of the upper-level power grid, there is a possibility that the power of the distributed power source cannot be effectively utilized.

[0005] An object of the present disclosure is to provide a technology capable of effectively utilizing power of a distributed power source during a power outage of an upper-level power grid.

[0006] To achieve the above object, in one embodiment of the present disclosure, there is provided: a power storage device mounted on a vehicle; an electric motor mounted on the vehicle, the electric motor driving driving wheels of the vehicle with electric power from the power storage device; a first power converter mounted on the vehicle and electrically connected to the power storage device; an electrical load provided in a residence or a facility; a power supply unit provided in the residence or the facility, electrically connected to an AC power system, and supplying power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch that switches between an electrically connected state and a disconnected state between the power supply unit and the AC power system, wherein the switch is switched to the disconnected state during a power outage of the AC power system, and when the power supply unit and the vehicle are electrically connected by the power connection unit, the first power converter operates to function as a predetermined power source for the power supply unit using the power of the power storage device during a power outage of the AC power system. A power system is provided.

[0007] Furthermore, in other embodiments of the present disclosure, a power converter is provided which is mounted on a vehicle together with a power storage device and an electric motor that drives the vehicle's drive wheels with the power of the power storage device, and which is installed in a dwelling or facility and is electrically connected to an AC power system via a switch that switches between an electrical connected state and a disconnected state, and which supplies power to the electrical load of the dwelling or facility, and which is electrically connectable to a power supply unit via a power connection unit, and which operates to function as a predetermined power source for the power supply unit using the power of the power storage device when the AC power system is shut off.

[0008] Furthermore, in yet another embodiment of the present disclosure, a control device for controlling a power system comprising: an energy storage device mounted on a vehicle; an electric motor mounted on the vehicle that drives the drive wheels of the vehicle with the power of the energy storage device; a first power converter mounted on the vehicle and electrically connected to the energy storage device; an electrical load provided in a dwelling or facility; a power supply unit provided in the dwelling or facility and electrically connected to an AC power system to supply power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch for switching between an electrical connection state and a disconnection state between the power supply unit and the AC power system, wherein in the event of a power outage in the AC power system, the control device switches the switch to the disconnection state. When the power supply unit and the first power converter are electrically connected by the power connection unit, a control device is provided that operates the first power converter to function as a predetermined power source for the power supply unit using the power of the energy storage device in the event of a power outage in the AC power system.

[0009] Furthermore, in yet another embodiment of the present disclosure, a control method for controlling a power system having: an energy storage device mounted on a vehicle; an electric motor mounted on the vehicle that drives the drive wheels of the vehicle with the power of the energy storage device; a first power converter mounted on the vehicle and electrically connected to the energy storage device; an electrical load provided in a dwelling or facility; a power supply unit provided in the dwelling or facility and electrically connected to an AC power system to supply power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch for switching between an electrical connection state and a disconnection state between the power supply unit and the AC power system, wherein in the event of a power outage in the AC power system, the switch is switched to the disconnection state. When the power supply unit and the first power converter are electrically connected by the power connection unit, a control method is provided to operate the first power converter so as to function as a predetermined power source for the power supply unit using the power of the energy storage unit in the event of a power outage in the AC power system.

[0010] According to the above embodiment, the power from distributed power sources can be effectively utilized in the event of a power outage in the higher-level power grid.

[0011] This is a diagram showing the configuration of the first example of a power system. This is a diagram showing the first example of a circuit configuration for power exchange between residential electrical equipment and electric vehicles. This is a diagram showing the second example of a circuit configuration for power exchange between residential electrical equipment and electric vehicles. This is a sequence diagram schematically showing the first example of the operation of a power system. This is a sequence diagram schematically showing the second example of the operation of a power system. This is a diagram showing the configuration of the second example of a power system. This is a sequence diagram schematically showing the third example of the operation of a power system. This is a diagram showing the configuration of the third example of a power system. This is the third example of a circuit configuration for power exchange between residential electrical equipment and electric vehicles. This is the fourth example of a circuit configuration for power exchange between residential electrical equipment and electric vehicles.

[0012] Embodiments will be described below with reference to the drawings.

[0013] [Outline of the First Example of the Power System] An outline of the first example of the power system 1 according to this embodiment will be described with reference to Figure 1.

[0014] Figure 1 shows the configuration of a first example of power system 1.

[0015] As shown in Figure 1, the power system 1 includes a power grid 10, electrical equipment 20, a rapid charger 30, and an electric vehicle 40.

[0016] The power system 10 generates, transmits, transforms, and distributes electricity to consumers.

[0017] The electrical equipment 20 is installed in the residential building (HM) and handles the exchange of electricity with the outside of the HM, such as the power grid 10 and electric vehicles 40, as well as the distribution of electricity within the HM. The residential building (HM) is, for example, a detached house. Alternatively, the residential building (HM) may be an apartment building.

[0018] Furthermore, the electrical equipment 20 may be installed in some facility and may exchange power with the outside of the facility, such as the power grid 10 or electric vehicles 40, and distribute power within the facility. The same applies to the second and third examples of power system 1 described below. Facilities include, for example, parking lots of commercial facilities such as shopping malls, parking lots of industrial facilities such as factories and distribution centers, automobile dealerships, highway service areas, etc.

[0019] The rapid charger 30 is electrically connected to the electric vehicle 40 via a charging cable 31 and charges the electric vehicle 40's high-voltage battery 41 (so-called rapid charging) by supplying a relatively high voltage (for example, 350V (volts)) of direct current. The rapid charger 30 is installed in a location separate from the residential building (HM). This separate location could be a parking lot of a commercial facility such as a shopping mall, a parking lot of an industrial facility such as a factory or distribution center, a car dealership, or a highway service area. Alternatively, the rapid charger 30 may be installed in the residential building (HM).

[0020] In Figure 1, for convenience, the electric vehicle 40 is shown to be electrically connected to both the electrical equipment 20 and the rapid charger 30. However, the electric vehicle 40 is configured to be electrically connectable to only one of the two.

[0021] The electric vehicle 40 is equipped with a high-voltage battery 41, and by driving an electric motor 42 as a prime mover with the power from the high-voltage battery 41, it is possible to drive the drive wheels with the power of the electric motor 42 and move forward. Examples of electric vehicles 40 include BEVs (Battery Electric Vehicles), HEVs (Hybrid Electric Vehicles), PHEVs (Plug-in Hybrid Electric Vehicles), FCVs (Fuel Cell Vehicles), REEVs (Range Extender Electric Vehicles), etc. The electric vehicle 40 can be electrically connected to the electrical equipment 20 of a residence HM via a charge / discharge cable 26. This allows the electric vehicle 40 to charge the high-voltage battery 41 by converting the alternating current supplied from the electrical equipment 20 of the residence HM to direct current, or to discharge the power from the high-voltage battery 41 to the electrical equipment 20 of the residence HM by converting the power from the high-voltage battery 41 to alternating current.

[0022] The electric vehicle 40 may be parked in a parking space adjacent to the residential building (HM). The electric vehicle 40 is, for example, a private car used by a resident of the residential building. Alternatively, the electric vehicle 40 may be a car-sharing vehicle deployed in a parking space adjacent to the residential building. When the electric vehicle 40 is parked in the parking space of the residential building, it is electrically connected to the electrical equipment 20 by its user or a resident of the residential building by connecting the connector at the end of the charge / discharge cable 26 installed at the residential building to its own charge / discharge port 45. As a result, the power system 1 can exchange power between the electrical equipment 20 of the residential building and the high-voltage battery 41 of the electric vehicle 40 via the charge / discharge cable 26.

[0023] In this specification, the explanation will primarily focus on the case where an electric vehicle 40 is parked in the parking space of a residential building (HM).

[0024] Furthermore, the rapid charging function using the rapid charger 30 may be omitted for the electric vehicle 40. The same applies to the second to fourth examples of the power system 1 described below.

[0025] [Configuration of the first example of the power system] In addition to Figure 1, the configuration of the first example of the power system 1 will be specifically described with reference to Figures 2 and 3.

[0026] Figure 2 shows a first example of a circuit configuration for power exchange between the electrical equipment 20 of a residential building (HM) and an electric vehicle 40. Figure 3 shows a second example of a circuit configuration for power exchange between the electrical equipment 20 of a residential building (HM) and an electric vehicle 40.

[0027] <Power System> As shown in Figure 1, the power system 10 includes a transmission system 11 and a distribution system 12.

[0028] The transmission system 11 transmits alternating current power. The distribution system 12 branches off from the transmission system 11 and distributes the alternating current power transmitted by the transmission system 11 to consumers. The distribution system 12 includes distribution systems 12A and 12B.

[0029] Distribution system 12A distributes power to the electrical equipment 20 of the residential building (HM). For example, distribution system 12A gradually steps down the ultra-high voltage (e.g., several hundred thousand volts) of transmission system 11 via a distribution substation and transformer (e.g., a transformer on a utility pole) not shown, and distributes 200V (volts) single-phase AC power to the electrical equipment 20 of the residential building (HM) using a single-phase three-wire system.

[0030] The power distribution system 12B supplies power to the rapid charger 30. For example, the power distribution system 12B gradually steps down the ultra-high voltage (e.g., several hundred thousand volts) of the transmission system 11 via a distribution substation and transformer (e.g., a transformer on a utility pole) not shown, and distributes 200V three-phase AC power to the rapid charger 30 using a three-phase three-wire system.

[0031] <Electrical Equipment> As shown in Figure 1, the electrical equipment 20 includes an electrical load 21, a power supply unit 22, a switch 23, a switch 24, a circuit breaker 25, a charging / discharging cable 26, and an EMS (Energy Management System) 27.

[0032] The electrical load 21 is connected to the power line PL24 and operates using alternating current supplied from the power supply unit 22. It operates using the alternating current of the power line PL24. The electrical load 21 includes, for example, at least one of an electrical load that is electrically connected in a fixed manner to the power line PL25 and an electrical load that is electrically connected in a detachable manner to an outlet at the end of the power line PL24.

[0033] The power supply unit 22 is electrically connected to the power distribution system 12A, the charge / discharge cable 26, and the electrical load 21, and facilitates the exchange of electricity between connected devices. The power supply unit 22 includes power lines PL21 to PL24, an isolation transformer 22A, and a filter capacitor 22B.

[0034] Power lines PL21 to PL25 are AC power transmission paths. Power line PL21 has one end connected to the distribution system 12A and the other end connected in parallel to power lines PL22 and PL23, respectively. Power line PL22 has one end connected to the base end of the charge / discharge cable 26 and the other end connected to power lines PL21 and PL23. Power line PL23 has one end connected in parallel to power lines PL21 and PL22, respectively, and the other end connected to multiple power lines PL24.

[0035] The isolation transformer 22A is installed on the power line PL22 and is a transformer that exchanges AC power while ensuring electrical isolation between the charging / discharging cable 26 side of the power line PL22 and the power lines PL21 and PL23 sides.

[0036] The filter capacitor 22B is installed between the isolation transformer 22A and the charge / discharge cable 26 in the power line PL22. The filter capacitor 22B removes high-frequency components from the output current of the inverter device 43 of the electric vehicle 40. For example, as shown in Figures 2 and 3, it is placed in the power line connecting the two power lines PL22L and PL22N that make up the power line PL22. This eliminates the need for the filter capacitor 22B to be installed in the electric vehicle 40, thereby suppressing increases in the cost and weight of the electric vehicle 40.

[0037] Furthermore, as shown in Figure 2, for example, the power supply unit 22 may include a DC cut-off capacitor 22C. The DC cut-off capacitor 22C is provided on the power line PL22N between the power line 26N of the charge / discharge cable 26 and the isolation transformer 22A.

[0038] Switch 23 is installed on power line PL21. Switch 23 is configured to electrically open and close power line PL21 under the control of EMS 27. As a result, the electrical equipment 20 of the residence HM can switch between an electrically connected state and an disconnected state between the distribution system 12A and the power lines PL22 and PL23 of the power supply unit 22 using switch 23. Switch 23 is, for example, a contactor. Alternatively, switch 23 may be, for example, a semiconductor switch.

[0039] The switch 24 is installed between the isolation transformer 22A and the charge / discharge cable 26 in the power line PL22, and is configured to electrically switch the power line PL22 under the control of the EMS 27. For example, as shown in Figures 2 and 3, the switch 24 is installed in the power line PL22L. This allows the EMS 27 to use the switch 24 to switch between the electrical connection state and the disconnection state between the electrical equipment 20 of the residence HM and the electric vehicle 40. The switch 24 is, for example, a contactor. Alternatively, the switch 24 may be, for example, a semiconductor switch.

[0040] Furthermore, at least one of the functions of the filter capacitor 22B and the switch 24 may be provided in the electric vehicle 40. In this case, for example, a filter capacitor similar to the filter capacitor 22B is provided in the power line connecting the power lines PL43 and PL44 of the electric vehicle 40. Also, for example, a switch similar to the switch 24 is provided in the power line PL43 of the electric vehicle 40.

[0041] The breaker 25 is a main breaker provided on a power line PL23 for supplying electric power to an electric load 21, for protecting the power line PL23. The breaker 25 is configured to be capable of electrically opening and closing the power line PL23, and can switch between an electrically connected state and an interrupted state between a power source and the electric load 21. Further, the breaker 25 may include a branch breaker (sub breaker) for each branch wiring (for example, the power line PL24) corresponding to each electric load 21.

[0042] The charging / discharging cable 26 has a base end connected to the power line PL22 and is provided so as to extend from the power line PL22. A connector that can be electrically connected to a charging / discharging port 45 of an electric vehicle 40 is provided at a tip end of the charging / discharging cable 26. The charging / discharging cable 26, together with the charging / discharging port 45 provided in the electric vehicle 40, functions as a power connection unit PC for connecting the electric equipment 20 and the electric vehicle 40 so that power can be exchanged therebetween. Accordingly, when the connector at the tip end of the charging / discharging cable 26 is connected to the charging / discharging port 45, the power supply system of the electric vehicle 40 and the electric equipment 20 of the residence HM can be electrically connected. Specifically, for example, as shown in FIG. 2 and FIG. 3, the charging / discharging cable 26 includes two power lines 26L, 26N provided so as to extend from the two power lines PL22L, PL22N, respectively.

[0043] The EMS 27 performs control related to the electric equipment 20 of the residence HM.

[0044] The functions of EMS27 are realized by any hardware or any combination of hardware and software. For example, EMS27 is centered around a computer including a processor, memory device, auxiliary storage device, and interface device. This allows EMS27 to realize various functions by loading programs installed in the auxiliary storage device into the memory device and executing them with the processor. The processor includes, for example, a CPU (Central Processing Unit). The processor may also include, for example, a GPU (Graphics Processing Unit), FPGA (Field Programmable Gate Array), CPLD (Complex Programmable Logic Device), ASIC (Application Specific Integrated Circuit), etc. The memory device is, for example, SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory). The auxiliary storage device is, for example, an HDD (Hard Disk Drive), SSD (Solid State Drive), EEPROM (Electrically Erasable Programmable Read Only Memory), flash memory, etc. The interface device includes, for example, an external interface for connecting to a recording medium and a communication interface for communicating with the outside. This allows, for example, the EMS 27 to install programs and data necessary for processing from the recording medium to the auxiliary storage device via the external interface. Furthermore, the EMS 27 can communicate with various devices of the electrical equipment 20 of the residential building (e.g., switches 23, 24, etc.) and external devices of the electrical equipment 20 of the residential building (e.g., the ECU 44 of the electric vehicle 40) via the communication interface. Additionally, for example, the EMS 27 can download programs and data necessary for processing from external devices using the communication interface and install them into the auxiliary storage device.

[0045] In this example, the EMS 27 cooperates with the ECU 44 of the electric vehicle 40 through two-way communication with the ECU 44 to perform control related to power exchange between the electrical equipment 20 of the residence HM and the electric vehicle 40. Communication between the EMS 27 and the ECU 44 is performed by wire, for example, using the charging / discharging cable 26 as a transmission path. Further, communication between the EMS 27 and the ECU 44 may be performed wirelessly by predetermined short-range communication such as Bluetooth (registered trademark) or WiFi, for example.

[0046] For example, when causing power to be supplied from the electrical equipment 20 of the residence HM to the electric vehicle 40, the EMS 27 transmits a command to the ECU 44 to appropriately operate the inverter device 43 of the electric vehicle 40 so as to convert alternating current from the electrical equipment 20 into direct current. Accordingly, the EMS 27 can control the inverter device 43 through the ECU 44 to cause the high-voltage battery 41 of the electric vehicle 40 to be charged with power from the electrical equipment 20 of the residence HM. The power supplied from the electrical equipment 20 to the electric vehicle 40 is power supplied from the power distribution system 12A to the power supply unit 22.

[0047] Further, for example, when causing discharge from the high-voltage battery 41 of the electric vehicle 40 to the electrical equipment 20 of the residence HM, the EMS 27 transmits a command to the ECU 44 to appropriately operate the inverter device 43 of the electric vehicle 40 so as to convert the output of the high-voltage battery 41 into alternating current. Accordingly, the EMS 27 controls the inverter device 43 through the ECU 44, and causes the power of the high-voltage battery 41 of the electric vehicle 40 to be discharged to the electrical equipment 20 of the residence HM, thereby realizing power supply from the electric vehicle 40 to the electrical equipment 20 of the residence HM.

[0048] Further, for example, when power exchange between the electrical equipment 20 of the residence HM and the electric vehicle 40 is not to be performed, the EMS 27 opens the switch 24. Accordingly, for example, even in a state where a connector at the tip of the charging / discharging cable 26 is connected to the charging / discharging port 45 of the electric vehicle 40, power exchange between the electrical equipment 20 of the residence HM and the electric vehicle 40 can be prohibited.

[0049] Furthermore, for example, when the EMS 27 discharges from the high-voltage battery 41 of the electric vehicle 40 to the electrical equipment 20 of the residence HM, it opens the switch 23. This allows the EMS 27 to prohibit connection between the power supply system of the electric vehicle 40 and the power grid 10 via the electrical equipment 20 of the residence HM. Therefore, the power system 1 can supply power from the high-voltage battery 41 of the electric vehicle 40 to the electrical equipment 20 of the residence HM using the inverter device 43 of the electric vehicle 40, which would otherwise be difficult to use to meet the connection requirements to the power grid 10.

[0050] Furthermore, if the inverter device 43 satisfies the interconnection requirements for the power system 10, it is not necessary to open the switch 23 even when discharging from the high-voltage battery 41 of the electric vehicle 40 to the electrical equipment 20 of the residence HM.

[0051] Furthermore, the EMS 27 may discharge power from the high-voltage battery 41 of the electric vehicle 40 to the electrical equipment 20 of the residence HM when the power supply from the distribution system 12A to the electrical equipment 20 is interrupted, that is, when the power system 10 is shut off. In this case, the EMS 27, for example, switches the switch 23 to the open state in conjunction with the occurrence of a power outage in the power system 10. The same may apply to the second example described below. This allows the EMS 27 to electrically disconnect the power distribution system 12A and the electrical equipment 20 when the power system 10 is shut off, preventing reverse power flow from the electrical equipment 20 to the power system 10, and also preventing the effects of the power system 10 related to the power outage (for example, the effects of a short circuit) from affecting the electrical equipment 20. Specifically, for example, the EMS 27 may discharge power from the high-voltage battery 41 to the electrical equipment 20 of the residence HM by controlling the inverter device 43 via the ECU 44 when the power system 10 is shut off. Furthermore, the EMS 27 may, in the event of a power outage in the power system 10, determine the charge level of the high-voltage battery 41 by communicating with the ECU 44. The EMS 27 may then determine that discharge from the high-voltage battery 41 is possible, but only if the charge level of the high-voltage battery 41 is relatively large compared to a predetermined standard, and control the inverter device 43 via the ECU 44 to discharge the power from the high-voltage battery 41 to the electrical equipment 20 of the residential building (HM). This allows the EMS 27 to discharge the power from the high-voltage battery 41 of the electric vehicle 40 to operate the electrical load 21 of the residential building (HM) in the event of a power outage in the power system 10. As a result, the residents of the residential building (HM) can continue to use the electrical load 21 with the power from the high-voltage battery 41 for at least part of the period until the power outage in the power system 10 is restored. This allows the EMS 27 to effectively utilize the high-voltage battery 41 of the electric vehicle 40 as an emergency power source for the electrical equipment 20 of the residential building (HM) in the event of a power outage in the power system 10. Details of the operation of the EMS 27 during a power outage in the power system 10 will be described later (see, for example, Figures 4 and 5).

[0052] Furthermore, in this specification, "power outage" is a concept that includes not only situations in which the power system 10 becomes 0V (volts) due to a short circuit or open circuit, but also situations in which an abnormality occurs in the power system 10, such as a deviation from a predetermined frequency range or a voltage increase or decrease that exceeds a predetermined standard.

[0053] <Rapid Charger> As shown in Figure 1, the rapid charger 30 is configured to convert the alternating current distributed from the power distribution system 12B into a relatively high-voltage direct current and output it. The rapid charger 30 includes a charging cable 31.

[0054] The charging cable 31 is provided so as to extend from the main body of the rapid charger 30. The tip of the charging cable 31 is provided with a connector that can be electrically connected to the charging port 46 of the electric vehicle 40. As a result, the connector at the tip of the charging cable 31 is connected to the charging port 46, thereby connecting the rapid charger 30 to the DC power system of the electric vehicle 40. Therefore, the rapid charger 30 can supply power to the DC power system of the electric vehicle 40 through the charging cable 31 and rapidly charge the high-voltage battery 41 of the electric vehicle 40.

[0055] <Electric Vehicle> As shown in Figure 1, the electric vehicle 40 includes power lines PL41 to PL45, a high-voltage battery 41, an electric motor 42, an inverter device 43, an ECU (Electronic Control Unit) 44, a charging / discharging port 45, and a charging port 46.

[0056] Power line PL41 is a DC power line connecting the high-voltage battery 41 and the inverter device 43.

[0057] Power line PL42 is an AC power line connecting the inverter device 43 and the motor 42. Specifically, as shown in Figures 2 and 3, for example, power line PL42 includes a three-phase AC U-phase line PL42u, a V-phase line PL42v, and a W-phase line PL42w.

[0058] Power line PL43 is an AC power line connecting the motor 42 and the charging / discharging port 45. Specifically, as shown in Figures 2 and 3, for example, power line PL43 connects the neutral point 43NP of the armature 42A of the motor 42 to the charging / discharging port 45. With the charging / discharging port 45 connected to the connector at the end of the charging / discharging cable 26, power line PL43 is connected to the power line 26L of the charging / discharging cable 26.

[0059] Power line PL44 is a reference potential line that connects the charging / discharging port 45 and the DC link 43DC of the inverter device 43. With the charging / discharging port 45 and the connector at the end of the charging / discharging cable 26 connected, power line PL44 is connected to the power line 26N of the charging / discharging cable 26.

[0060] For example, as shown in Figure 2, power line PL44 is connected to power line PL22N through power line 26N of the charge / discharge cable 26. A DC cut-off capacitor 22C is provided on power line PL22N of the electrical equipment 20 of the residence HM. As a result, when power is exchanged between the electrical equipment 20 of the residence HM and the electric vehicle 40, the DC cut-off capacitor 22C removes the DC component from the AC at the neutral point 43NP of the armature 42A that occurs between it and power line PL44, which acts as a reference potential line, and generates a single-phase AC voltage that does not contain a DC component. In addition, by providing the DC cut-off capacitor 22C on the electrical equipment 20 of the residence HM, the increase in cost and weight of the electric vehicle 40 can be suppressed.

[0061] Furthermore, as shown in Figure 3, the power line PL44 may be connected to the midpoint of the balanced smoothing capacitors 43c1 and 43c2 in the DC link 43DC. This allows the smoothing capacitors 43c1 and 43c2 to perform the same function as the DC cut-off capacitor 22C. As a result, the increase in cost and weight of the electric vehicle 40 can be suppressed, as well as the overall cost of the electrical equipment 20 of the residence HM and the power supply system of the electric vehicle 40.

[0062] Power line PL45 is a DC power line connecting the high-voltage battery 41 and the charging port 46.

[0063] The high-voltage battery 41 is a storage battery having a relatively high output voltage (for example, several hundred volts). The high-voltage battery 41 is, for example, a liquid-type lithium-ion battery. Alternatively, the high-voltage battery 41 may be an all-solid-state battery. The high-voltage battery 41 is equipped with sensors capable of measuring various states such as current, voltage, and temperature. The output of the sensors mounted on the high-voltage battery 41 is received by the ECU 44 via a one-to-one communication line or an in-vehicle network such as CAN (Controller Area Network) or in-vehicle Ethernet.

[0064] The electric motor 42 is the prime mover that drives the drive wheels of the electric vehicle 40. The electric motor 42 is driven by three-phase alternating current supplied from the inverter device 43. Specifically, as shown in Figures 2 and 3, the electric motor 42 includes an armature 42A as a stator, and the armature 42A includes a U-phase winding 42u, a V-phase winding 42v, and a W-phase winding 42w connected in a Y-connection.

[0065] The inverter device 43 drives the motor 42 by converting the DC supplied from the high-voltage battery 41 through the power line PL 41 into a three-phase AC of a predetermined voltage and frequency, and outputting it to the power line PL 42. Specifically, as shown in Figures 2 and 3, the inverter device 43 includes a smoothing circuit 43A and an inverter circuit 43B. The inverter device 43 is also equipped with sensors capable of measuring various states of the inverter device 43, such as current, voltage, and temperature. The output of the sensors mounted on the inverter device 43 is taken up by the ECU 44 via a one-to-one communication line or an in-vehicle network such as CAN (Controller Area Network) or in-vehicle Ethernet.

[0066] The smoothing circuit 43A suppresses and smooths the pulsations of the DC output from the high-voltage battery 41 and the DC output from the inverter circuit 43B. The smoothing circuit 43A includes a smoothing capacitor 43c of the DC link 43DC. For example, as shown in Figure 2, the smoothing capacitor 43c is provided on the power line connecting the positive line 43P and the negative line 43N of the DC link 43DC. The smoothing capacitor 43c may consist of one capacitor or multiple capacitors. For example, as shown in Figure 3, the smoothing capacitor 43c is composed of multiple (two in this example) smoothing capacitors 43c1 and 43c2 connected in series between the positive line 43P and the negative line 43N. As described above, by connecting one end of the power line PL 44 to the midpoint between two adjacent smoothing capacitors connected in series, it is possible to give it a function similar to that of a DC cut-off capacitor. Furthermore, even if a short-circuit failure occurs in some of the multiple capacitors connected in series between the positive line 43P and the negative line 43N, the smoothing capacitor 43c, which is a series connection of multiple capacitors, can avoid a fatal failure. Therefore, the inverter device 43 can continue to operate, although some limitations may arise.

[0067] The inverter circuit 43B has the positive line 43P and negative line 43N of the DC link 43DC connected to one end, and the U-phase line PL42u, V-phase line PL42v, and W-phase line PL42w of the three-phase AC power line PL42 connected to the other end.

[0068] For example, as shown in Figures 2 and 3, the inverter circuit 43B includes six semiconductor switches 43sw. The semiconductor switches 43sw are, for example, IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), HEMTs (High Electron Mobility Transistors), etc. The semiconductor switches 43sw are, for example, constructed mainly from silicon (Si). Alternatively, the semiconductor switches 43sw may be constructed mainly from a wide-bandgap semiconductor material. Wide-bandgap semiconductor materials include, for example, silicon carbide (SiC), gallium nitride (GaN), and gallium oxide (Ga ２ O ３ Examples include carbon (diamond: C), etc. Specifically, the inverter circuit 43B includes a bridge circuit in which three sets of switch legs, each consisting of two semiconductor switches 43sw constituting the upper and lower arms connected in series, are connected in parallel between the positive line 43P and the negative line 43N. Then, U-phase line PL42u, V-phase line PL42v, and W-phase line PL42w are drawn out from the midpoint of the three sets of upper and lower arms of the bridge circuit and connected to the U-phase winding 42u, V-phase winding 42v, and W-phase winding 42w of the armature 42A, respectively. In addition, each of the six semiconductor switches 43sw may be connected in parallel with, for example, a recirculating diode 43d.

[0069] Furthermore, the inverter device 43 may be a multi-level system with three or more levels, rather than a two-level system. The same may apply to the second example of power system 1 described below. In this case, since the voltage of the DC link 43DC of the inverter device 43 is divided into multiple parts (two parts in the case of three levels), multiple voltage divider capacitors (two in the case of three levels) are arranged in series between the positive line 43P and the negative line 43N. For example, when a multi-level inverter device 43 is used, the power line PL 44 may be connected to the midpoint between the two capacitors arranged in series between the positive line 43P and the negative line 43N of the inverter device 43. This produces the same effect as when the power line PL 44 is connected to the midpoint between the smoothing capacitors 43c1 and 43c2 (see Figure 3).

[0070] When the electric vehicle 40 is in operation, the inverter circuit 43B, under the control of the ECU 44, performs switching operations of the semiconductor switch 43sw to convert the DC of the DC link 43DC to AC and output it to the power line PL 42, or convert the AC of the power line PL 42 to DC and output it to the DC link 43DC.

[0071] For example, when the electric vehicle 40 is running, the inverter circuit 43B converts the DC supplied from the DC link 43DC into a three-phase AC having a predetermined frequency and voltage and outputs it to the motor 42. This allows the inverter device 43 to drive the motor 42 and run the electric vehicle 40. Also, for example, when the electric vehicle 40 is decelerating, the inverter circuit 43B converts the AC generated power from the armature 42A into DC in response to the regenerative operation of the motor 42 and outputs it to the DC link 43DC. This allows the inverter device 43 to output the kinetic energy of the electric vehicle 40 during its running as electrical energy (i.e., regenerative energy) to the DC link 43DC, charging the high-voltage battery 41, and also generates braking force in the electric vehicle 40 through regeneration.

[0072] Furthermore, for example, when the electric vehicle 40 is stopped, the inverter circuit 43B converts the DC of the DC link 43DC to AC and supplies AC to the electrical equipment 20 of the residence HM through the neutral point 43NP of the armature 42A, the power line PL 42, and the charge / discharge cable 26. When the electric vehicle 40 is stopped, it means that the electric vehicle 40 is in a state where it cannot move, for example, when the accessory power of the electric vehicle 40 is off (ACC-OFF) or when the ignition power of the electric vehicle 40 is off (IG-OFF). As a result, the inverter device 43 can convert the output of the high-voltage battery 41 to AC and supply it to the electrical equipment 20 of the residence HM, and as a result, the electrical equipment 20 of the residence HM can operate the electrical load 21 with AC power supplied from the electric vehicle 40. Furthermore, when the electric vehicle 40 is stopped, the inverter circuit 43B converts the alternating current supplied through the charge / discharge cable 26, power line PL 42, and the neutral point 43NP of the armature 42A into direct current and outputs it to the DC link 43DC. As a result, the inverter device 43 can charge the high-voltage battery 41 using alternating current power supplied from the electrical equipment 20 of the residence HM.

[0073] Thus, in this example, the power system 1 can use the inverter device 43 to charge the high-voltage battery 41 with AC power supplied from the electrical equipment 20 of the residential building (HM), or to discharge power from the high-voltage battery 41 to the electrical equipment 20 of the residential building (HM) from the electric vehicle 40. Therefore, there is no need to install an additional power converter to convert power between the DC of the high-voltage battery 41 and the AC of the electrical equipment 20 of the residential building (HM), and the configuration for power exchange between the electrical equipment 20 of the residential building (HM) and the electric vehicle 40 can be simplified. In addition, since the installation of an additional power converter is unnecessary, the initial investment for power exchange between the electrical equipment 20 of the residential building (HM) and the electric vehicle 40 can be reduced. Furthermore, since the inverter device 43 is for driving the electric motor 42 and has a relatively large capacity, the power system 1 can use the inverter device 43 to charge the high-voltage battery 41 with a relatively large current using AC power supplied from the electrical equipment 20. Therefore, the power system 1 can use the inverter device 43 to achieve rapid charging using AC power supplied from the electrical equipment 20.

[0074] Furthermore, for example, when the electric vehicle 40 is stopped and the power system 10 experiences a power outage, the inverter device 43 operates under the control of the ECU 44, using the power from the high-voltage battery 41 to function as a predetermined power source that suppresses fluctuations in the voltage and frequency of the power supply unit 22. As a result, in the event of a power outage in the power system 10, the inverter device 43 can suppress situations in which the voltage and frequency of the power supply unit 22 fluctuate and the electrical load 21 stops operating, thereby ensuring the continued operation of the electrical load 21.

[0075] The specified power supply includes, for example, a Constant Voltage Constant Frequency (CVCF) power supply that has the function of maintaining a constant output voltage and frequency. In this case, the inverter device 43 operates as a voltage source. In this case, for example, the ECU 44 maintains a constant output voltage and frequency of the inverter device 43 by monitoring the voltage and frequency of the inverter device 43 using a known control algorithm and correcting fluctuations in real time.

[0076] Furthermore, the specified power supply includes, for example, a power supply that exhibits a pseudo-inertial force (also called "pseudo-inertia" or "virtual inertia") that mimics the inertial characteristics of a synchronous generator (also called a "virtual inertia power supply"). For example, the ECU 44 employs known pseudo-inertia control to detect fluctuations in voltage and frequency, and causes the inverter device 43 to perform operations to compensate for or absorb these fluctuations. In this case, the inverter device 43 can be considered to be operating as a voltage source in that it attempts to suppress voltage fluctuations.

[0077] Furthermore, the specified power source is, for example, a virtual synchronous generator (VSG). For example, the ECU 44 virtually reproduces the physical characteristics of a synchronous generator using a known control algorithm. The physical characteristics of a synchronous generator include inertial response characteristics, synchronous torque characteristics, voltage stabilization characteristics, and dynamic tracking characteristics. Inertial response characteristics are those that suppress frequency fluctuations and stabilize the frequency in response to fluctuations in the AC frequency of the power supply system (power supply unit 22) by rotational inertia. Synchronous torque characteristics are those that generate torque so that the rotor of the synchronous generator synchronizes (follows) the phase and frequency of the AC of the power supply system (power supply unit 22). Voltage stabilization characteristics are those that stabilize the voltage by adjusting the generated reactive power. Dynamic tracking characteristics are those that change the output of active power and reactive power in real time in response to voltage fluctuations in the power supply system (power supply unit 22). For example, the physical characteristics of a synchronous generator are implemented by a control algorithm based on various equations that represent the physical characteristics of a synchronous generator. In this case, the inverter device 43 can be considered to be operating as a voltage source in that it attempts to suppress voltage fluctuations.

[0078] Furthermore, the specified power supply is, for example, a power supply (GFM power supply) that has grid-forming characteristics, such as generating a reference voltage and frequency for other power supplies to follow. The characteristics of a GFM may include synchronous characteristics similar to those of a synchronous generator, similar to those of a virtual synchronous generator. Also, the characteristics of a GFM may include inertial characteristics that exert a pseudo-inertial force, similar to those of a virtual inertial power supply or virtual synchronous generator. For example, the ECU 44 can realize grid-forming characteristics using a known control algorithm, similar to those of a virtual inertial power supply or virtual synchronous generator. In this case, the inverter device 43 can be considered to be operating as a voltage source in that it attempts to suppress voltage fluctuations.

[0079] Furthermore, the specified power supply is, for example, a power supply (hereinafter referred to as a "stabilized GFL power supply") that has been simply modified to suppress and stabilize voltage and frequency fluctuations by assuming the characteristics of GFL (Grid-Following) instead of GFM characteristics (variability stabilization control). In this case, the inverter device 43 basically functions as a current source in a manner that follows the voltage and frequency of the power supply system (power supply unit 22). For example, the ECU 44, while operating as a current source, monitors the voltage and frequency of the inverter device 43 and corrects voltage and frequency fluctuations by feedback control.

[0080] When the inverter device 43 functions as a power source for the power supply unit 22, it may operate under the control of the ECU 44 to function as the predetermined power source at all times, or it may operate to function as the predetermined power source only when there is a power outage in the power system 10. In the latter case, for example, when the inverter device 43 functions as a power source for the power supply unit 22 during normal operation of the power system 10, it functions under the control of the ECU 44 to follow the voltage and frequency of the power supply unit 22, i.e., the voltage and frequency of the power system 10. Then, under the control of the ECU 44, the inverter device 43 switches to a state in which it functions as the predetermined power source in response to a power outage in the power system 10. Hereinafter, the state in which the inverter device 43 functions as a current source for the power supply unit 22 may be conveniently referred to as the "auxiliary power state," and the state in which the inverter device 43 functions as the predetermined power source for the power supply unit 22 may be referred to as the "main power state."

[0081] Thus, in this example, the power system 1 operates the inverter device 43 to function as a predetermined power source capable of suppressing voltage and frequency fluctuations to the power supply unit 22 in the event of a power outage in the power grid 10. As a result, the power system 1 can immediately start the independent operation of the inverter device 43 in the event of a power outage in the power grid 10, and reliably continue to supply power from the power supply unit 22 to the electrical load 21.

[0082] The ECU 44 is a control device for the electric vehicle 40. The electric vehicle 40 may have one or more ECUs 44. The same applies to the second to fourth examples of the power system 1 described below.

[0083] The functions of the ECU 44 are realized, for example, by arbitrary hardware, or by any combination of hardware and software. For example, the ECU 44 is mainly composed of a computer including a processor, memory device, auxiliary storage device, and interface device. This allows the ECU 44 to realize various functions by loading a program installed in the auxiliary storage device into the memory device and having the processor execute it. The processor includes, for example, a CPU. The processor may also include a GPU, FPGA, CPLD, ASIC, etc. The memory device is, for example, SRAM. The auxiliary storage device is, for example, EEPROM or flash memory. The interface device includes, for example, an external interface for connecting to a recording medium and a communication interface for communicating with the outside. This allows, for example, the ECU 44 to install programs and data necessary for processing from a portable recording medium to the auxiliary storage device via the external interface. The ECU 44 can also communicate with various devices of the electric vehicle 40 (for example, a high-voltage battery 41 or an inverter device 43, etc.) or external devices of the electric vehicle 40 (for example, an EMS 27) via the communication interface. Furthermore, for example, the ECU44 can use a communication interface to download programs and data necessary for processing from external devices and install them into auxiliary storage.

[0084] For example, when the electric vehicle 40 is in operation, the ECU 44 outputs a control command to the inverter device 43 and controls the drive of the electric motor 42 through the inverter device 43. When the electric vehicle 40 is in operation, it means that the electric vehicle 40 is in a state where it can be driven, for example, when the ignition power of the electric vehicle 40 is turned on (IG-ON). In this case, the ECU 44 may control the drive of the electric motor 42 in response to the operation of the steering wheel, accelerator pedal, brake pedal, etc. by the driver of the electric vehicle 40, or it may control the drive of the electric motor 42 in response to a higher-level command corresponding to so-called automatic driving. The same applies to the second to fourth examples of power system 1 described later.

[0085] Furthermore, when the electric vehicle 40 is stopped, the ECU 44 controls the inverter device 43 under the control of the EMS 27 to convert the AC power from power lines PL 43 and PL 42 to DC power and output it to the DC link 43DC. As a result, the ECU 44 can charge the high-voltage battery 41 with AC power supplied from the electrical equipment 20 of the residence HM in response to a command from the EMS 27.

[0086] Furthermore, when the electric vehicle 40 is stopped, the ECU 44 controls the inverter device 43 under the control of the EMS 27 to convert the DC of the DC link 43DC to AC and output it to the power lines PL 42 and PL 43. As a result, the ECU 44 can discharge the power from the high-voltage battery 41 to the electrical equipment 20 of the residence HM in response to the command from the EMS 27.

[0087] Furthermore, the ECU 44 transmits information from sensors mounted on the high-voltage battery 41 and sensors mounted on the inverter device 43 to the EMS 27. This allows the higher-level EMS 27 to understand the status of the high-voltage battery 41 and the inverter device 43.

[0088] The charging / discharging port 45 is provided on the body surface of the electric vehicle 40 and is configured to be connectable to the connector at the end of the charging / discharging cable 26 extending from the residence HM. For example, the charging / discharging port 45 is usually covered by an openable / closable cover member, and when the electric vehicle 40 is parked at the residence HM and connected to the connector of the charging / discharging cable 26, the cover member is opened by operation by the user of the electric vehicle 40 or the resident of the residence HM, or automatically, exposing the port to the outside.

[0089] The charging port 46, like the charge / discharge port 45, is provided on the surface of the electric vehicle 40's body and is configured to be connectable to the connector at the end of the charging cable 31 extending from the rapid charger 30. For example, the charging port 46 is usually covered by a retractable cover member, and when the electric vehicle 40 is parked near the rapid charger 30 and connected to the connector of the charging cable 31, the cover member is opened by user operation or automatically, exposing the port to the outside.

[0090] The charging / discharging port 45 and the charging port 46 are, for example, provided adjacent to each other and covered by the same cover member. Alternatively, the charging / discharging port 45 and the charging port 46 may be located in different places and covered by different cover members.

[0091] [First Example of Power System Operation] A first example of the operation of power system 1 will be explained with reference to Figure 4.

[0092] Figure 4 is a schematic sequence diagram illustrating a first example of the operation of power system 1.

[0093] Specifically, Figure 4 is a schematic sequence diagram showing an example of the operation of the first example of the power system 1 during a power outage in the power grid 10.

[0094] The operation shown in the sequence diagram of Figure 4 may be performed when the power system 1 does not have an islanding detection function for the power supply unit 22, or when the power system 1 has an islanding detection function for the power supply unit 22.

[0095] Furthermore, if the power system 1 does not have a function to detect the isolated operation of the power supply unit 22, and the power grid 10 is in a normal state and the switch 23 is ON, power will not be supplied from the electric vehicle 40 (specifically, the high-voltage battery 41) to the electrical equipment 20 (specifically, the power supply unit 22) (in other words, it will be prohibited).

[0096] As shown in Figure 4, under normal conditions of the power system 10, the power supply unit 22 of the electrical equipment 20 receives power from the power system 10 (step S102), and the electrical load 21 of the electrical equipment 20 operates by power supplied from the power supply unit 22 (step S104).

[0097] In this example, when the power system 10 is functioning normally, the inverter device 43 of the electric vehicle 40 charges the high-voltage battery 41 under the control of the ECU 44 by receiving power from the power supply unit 22 (step S106).

[0098] When the power system 10 is functioning normally, the inverter device 43 transitions to a standby state by ending the charging of the high-voltage battery 41 and stopping the charging and discharging of the high-voltage battery 41 when the conditions for ending the charging of the high-voltage battery 41 are met (step S108).

[0099] The charging termination condition is the condition for ending the charging of the high-voltage battery 41. The charging termination condition is, for example, when the charge level reaches a predetermined state (for example, a state equivalent to a full charge, or a charge level lower than the state equivalent to a full charge set in advance by the user, etc.), or when the charge level reaches a level that allows power to be supplied to the electrical load 21 for a predetermined time even if a power outage occurs in the power system 10. The state equivalent to a full charge of the high-voltage battery 41 is, for example, the state in which the entire rechargeable capacity of the high-voltage battery 41 is charged. Furthermore, the state equivalent to a full charge of the high-voltage battery 41 may be set as appropriate by the user, etc., taking into consideration the lifespan of the high-voltage battery 41, the cost required for charging (for example, electricity charges, etc.), and the cost-saving effect obtained by discharging. The predetermined time may be a fixed value defined in advance, or it may be a variable value that is changed by some condition.

[0100] In this example, the inverter device 43 transitions from the charging state to the standby state when the charging completion condition is met. However, if the power system 1 has a function to detect the independent operation of the power supply unit 22, it may transition from the charging state to the auxiliary power state described later. In this case, it transitions to the operation shown in the sequence diagram of Figure 5 described later. Also, in this example, the high-voltage battery 41 transitions from the charging state to the standby state when the charging completion condition is met, before the power outage detection of the power system 10 described later (step S110). However, it is possible that a power outage in the power system 10 may be detected before the charging completion condition of the high-voltage battery 41 is met. In this case, in step S116 described later, the inverter device 43 transitions from the charging state to the main power state described later.

[0101] When a power outage occurs in the power system 10, the EMS 27 of the electrical equipment 20 detects the power outage in the power system 10 based on the voltage detection value on the distribution system 12A side of the switch 23 in the power line PL 21 (step S110).

[0102] In response to detecting a power outage in the power system 10, the EMS 27 switches the switch 23 from ON (closed) to OFF (open) (step S112).

[0103] This allows the EMS 27 to transition from a connected state to a disconnected state between the power distribution system 12A and the power supply unit 22.

[0104] After the completion of step S112, the EMS 27 sends a power outage signal to the ECU 44 of the electric vehicle 40 (step S114).

[0105] Furthermore, the order of processing in steps S112 and S114 may be reversed, or they may be performed simultaneously in parallel.

[0106] As a result, the ECU 44 can receive a power outage signal and understand that a power outage has occurred in the power system 10. Furthermore, the ECU 44 can start controlling the inverter device 43 corresponding to the power outage in the power system 10 in accordance with the command specified by the power outage signal.

[0107] In response to receiving a power outage signal from the ECU 44, the inverter device 43 of the electric vehicle 40 transitions from standby to main power state under the control of the ECU 44 (step S116).

[0108] Furthermore, if the inverter device 43 has the function of the predetermined power source (for example, a virtual synchronous generator), the processing in steps S112 and S116 may be performed in a different order or simultaneously in parallel. Specifically, after detecting a power outage in the power system 10 in step S110, the processing in step S114 may be executed, and after the inverter device 43 of the electric vehicle 40 transitions from a standby state to a main power state by the processing in step S116, step S112 may be executed, and the connection between the power distribution system 12A and the power supply unit 22 may transition from a connected state to a disconnected state. In this case, since the inverter device 43 functions as the predetermined power source, voltage can be applied to the electrical load 21 even during the period from the occurrence of a power outage in the power system 10 until the switch 23 transitions to a disconnected state. Furthermore, as described above, the switch 23 may be a semiconductor switch. In this case, the power system 10 experiencing a power outage and the inverter device 43 can be quickly disconnected. This allows the power supply from the inverter device 43 to the point of abnormality in the power system 10 to be quickly interrupted. In other words, the inverter device 43 can be switched to the main power state without any interruption.

[0109] Then, the high-voltage battery 41 discharges to the electrical equipment 20 through the inverter device 43, which is in the main power state (step S118).

[0110] As a result, the power supply unit 22 of the electrical equipment 20 can receive power from the high-voltage battery 41 of the electric vehicle 40 through the inverter device 43 (step S120).

[0111] Therefore, the electrical load 21 of the electrical equipment 20 can continue to operate by receiving power from the power supply unit 22 (step S122).

[0112] Furthermore, if a power outage signal is received by the ECU 44 while the high-voltage battery 41 is being charged, the inverter device 43 will switch from the state of charging the high-voltage battery 41 (charging state) to the main power state under the control of the ECU 44.

[0113] Subsequently, when the power system 10 is restored from the blackout (power is restored), the EMS 27 of the electrical equipment 20 detects the restoration of power to the power system 10 based on the voltage detection value on the distribution system 12A side of the switch 23 in the power line PL 21 (step S124).

[0114] In response to the detection of power restoration in the power system 10, the EMS 27 transmits a power restoration signal to the ECU 44 of the electric vehicle 40 (step S126).

[0115] As a result, the ECU 44 can receive the power restoration signal and determine that power has been restored to the power system 10. Furthermore, the ECU 44 can return to controlling the inverter device 43 corresponding to the normal state of the power system 10, in accordance with the command specified by the power restoration signal.

[0116] In response to receiving a power restoration signal from the ECU 44, the inverter device 43 of the electric vehicle 40 synchronizes with the frequency and phase of the power system 10 and adjusts the voltage under the control of the ECU 44 (step S128).

[0117] After the completion of the process in step S126, the EMS 27 of the electrical equipment 20 switches the switch 23 from OFF (open) to ON (closed) (step S130).

[0118] Once the process in step S128 is complete, the inverter device 43 transitions from the main power state to the standby state under the control of the ECU 44 (step S132).

[0119] In step S132, the inverter device 43 may transition from the main power state to the charging state. For example, if the inverter device 43 transitions from the charging state to the main power state in response to receiving a power outage signal from the ECU 44, it may transition from the main power state to the charging state after the power system 10 is restored and the switch 23 is switched from OFF to ON, and resume charging the high-voltage battery 41.

[0120] This allows the EMS 27 to transition from a disconnected state to a connected state between the power distribution system 12A and the power supply unit 22, thereby resuming the power supply from the power distribution system 12A to the power supply unit 22.

[0121] [Second Example of Power System Operation] A second example of the operation of power system 1 will be explained with reference to Figure 5.

[0122] Figure 5 is a schematic sequence diagram illustrating a second example of the operation of power system 1.

[0123] Specifically, Figure 5 is a schematic sequence diagram illustrating another example of the operation of the first example of the power system 1 during a power outage in the power grid 10.

[0124] The sequence of operations shown in Figure 5 is executed when the power system 1 has a function to detect the isolated operation of the power supply unit 22.

[0125] In this example, since the power system 1 has a function to detect the isolated operation of the power supply unit 22, assuming that the electric vehicle 40 satisfies other interconnection requirements, and assuming that the power system 10 is in a normal state and the switch 23 is ON, power can be supplied from the electric vehicle 40 (specifically, the high-voltage battery 41) to the electrical equipment 20 (specifically, the power supply unit 22) (in other words, it is permitted).

[0126] As shown in Figure 5, under normal operation of the power system 10, the inverter device 43 of the electric vehicle 40 is in an auxiliary power state under the control of the ECU 44, and the high-voltage battery 41 is discharging through the inverter device 43 (step S202).

[0127] Furthermore, when the power system 10 is functioning normally, the power supply unit 22 of the electrical equipment 20 receives power from the electric vehicle 40 in addition to the power supply from the power system 10 (step S204), and the electrical load 21 of the electrical equipment 20 operates using power supplied from the power supply unit 22 (step S206).

[0128] When a power outage occurs in the power system 10, the EMS 27 of the electrical equipment 20 detects islanding of the power supply unit 22 by its islanding detection function based on the injection of reactive power, etc. (step S208).

[0129] In response to the detection of independent operation of the power supply unit 22, the EMS 27 switches the switch 23 from ON (closed) to OFF (open) (step S210).

[0130] This allows the EMS 27 to transition from a connected state to a disconnected state between the power distribution system 12A and the power supply unit 22.

[0131] After the completion of step S210, the EMS 27 transmits an isolated operation detection signal to the ECU 44 of the electric vehicle 40 (step S212).

[0132] Furthermore, the order of processing in steps S210 and S212 may be reversed, or they may be performed simultaneously in parallel.

[0133] As a result, the ECU 44 can receive the islanding detection signal and understand the islanding state of the power supply unit 22 (i.e., a power outage has occurred in the power system 10). Furthermore, the ECU 44 can start controlling the inverter device 43 corresponding to the power system 10 power outage in accordance with the command specified by the islanding detection signal.

[0134] In response to the ECU 44 receiving an isolated operation detection signal, the inverter device 43 of the electric vehicle 40 switches from the auxiliary power state to the main power state under the control of the ECU 44 (step S214).

[0135] Furthermore, if the inverter device 43 has the function of the predetermined power source (for example, a virtual synchronous generator), the order of steps S210 and S214 may be reversed, or they may be performed simultaneously in parallel. Specifically, after the independent operation of the power supply unit 22 is detected in step S208, the process in step S212 may be executed, and after the inverter device 43 of the electric vehicle 40 transitions from a standby state to a main power state by the process in step S214, the process in step S210 may be executed, and the connection between the power distribution system 12A and the power supply unit 22 may transition from a connected state to a disconnected state. In this case, since the inverter device 43 functions as the predetermined power source, voltage can be applied to the electrical load 21 even during the period from the occurrence of a power outage in the power system 10 until the switch 23 transitions to a disconnected state. Furthermore, as described above, the switch 23 may be a semiconductor switch. In this case, the power system 10 experiencing a power outage and the inverter device 43 can be quickly disconnected. This allows the power supply from the inverter device 43 to the point of abnormality in the power system 10 to be quickly cut off. In other words, the inverter device 43 can be switched to the main power state without any interruption.

[0136] Then, the high-voltage battery 41 continues to discharge to the electrical equipment 20 through the inverter device 43, which is in the main power state (step S216).

[0137] Steps S218, S220, S222, S224, S226, and S228 are the same as the processes in steps S116, S118, S120, S122, S124, and S132 in Figure 4, so their explanation is omitted.

[0138] Under the control of the ECU 44, the inverter device 43 of the electric vehicle 40 maintains the main power state after switching the switch 23 from OFF (open) to ON (closed) (step S228), and continues to supply power to the power supply unit 22 for a certain period of time (step S230).

[0139] As a result, even if a power outage occurs again immediately after the switch 23 is switched from OFF to ON and isolated operation is detected, the inverter device 43 can instantly resume supplying power to the power supply unit 22.

[0140] If no power outage occurs in the power system 10 and a certain period of time has elapsed since step S230, the inverter device 43 transitions from the main power state to the standby state under the control of the ECU 44 (step S232).

[0141] Furthermore, the inverter device 43 may transition from the main power state to the state of step S202, i.e., the auxiliary power state, under the control of the ECU 44. Alternatively, instead of transitioning from the main power state to the standby state, the inverter device 43 may transition to the charging state regardless of other conditions. This allows the inverter device 43 to replenish the discharged portion of the high-voltage battery 41, which is expected to be discharged from the high-voltage battery 41 and have a reduced charge rate when the inverter device 43 is in the main power state. The inverter device 43 may also transition from the main power state to the charging state and start charging the high-voltage battery 41 in response to the fulfillment of certain conditions (for example, conditions for starting charging of the high-voltage battery 41). The conditions for starting charging of the high-voltage battery 41 are, for example, that the charge rate of the high-voltage battery 41 is below a predetermined standard or has fallen below a predetermined standard. The predetermined standard is, for example, predetermined considering the deterioration of the high-voltage battery 41. The predetermined standard may also be set by the user or the like within a range higher than the lower limit value determined considering the deterioration of the high-voltage battery 41.

[0142] [Configuration of the second example of the power system] Referring to Figure 6, the configuration of the second example of the power system 1 according to this embodiment will be described.

[0143] In the following examples, components identical to or corresponding to those in the first example of power system 1 (Figure 1) described above are denoted by the same reference numerals. The explanation will focus on the parts that differ from the first example, and the explanation of parts that are the same as or corresponding to the first example may be omitted.

[0144] Figure 6 shows the configuration of a second example of power system 1.

[0145] As shown in Figure 6, the power system 1 in this example differs from the first example described above mainly in that the electrical equipment 20 includes a solar power generator 29. Furthermore, the power system 1 in this example may be the same as the first example described above in other respects.

[0146] The solar power generator 29 includes solar panels 29A and a power conditioner (PCS: Power Conditioning System) 29B.

[0147] The solar panel 29A converts solar energy into electrical energy and outputs it. The PCS 29B converts the DC output from the solar panel 29A into AC output and outputs it to the power line PL23. In this process, the PCS 29B can efficiently extract power from the solar panel 29A by, for example, operating to search for the optimal operating point using a known MPPT (Maximum Power Point Tracking) method.

[0148] Unlike the first example described above, the power supply unit 22 includes a power line PL25.

[0149] PCS29B is connected to one end of power line PL25, and the other end of power line PL25 is connected to the portion of power line PL23 on the upstream side from the breaker 25, i.e., the side opposite to the electrical load 21. This allows the solar power generator 29 to supply power to the electrical load 21 from power line PL25 through power line PL23. The solar power generator 29 can also connect to the power grid 10 from power line PL23 through power line PL21 and supply power to the power grid 10. Furthermore, the solar power generator 29 can supply power to the electric vehicle 40 from power line PL23 through power line PL22 and the charge / discharge cable 26.

[0150] When switch 23 is ON, PCS29B operates to follow the voltage and frequency of the power system 10, that is, to have GFL characteristics, and acts as a current source. Furthermore, when switch 23 is OFF, PCS29B can operate independently.

[0151] Furthermore, the electrical equipment 20 of the residential HM may be equipped with other power sources in place of or in addition to the solar power generator 29. These other power sources may be, for example, a combination of a fuel cell and a PCS. Alternatively, the other power sources may be generators using prime movers such as gas engines or gas turbines. Alternatively, the other power sources may be power sources derived from other types of renewable energy, such as wind turbines or geothermal generators. Alternatively, the other power sources may be, for example, a combination of a battery (storage battery) such as a lithium-ion battery or a solid-state battery and a PCS.

[0152] For example, when the EMS 27 supplies power from the electrical equipment 20 of the residential building (HM) to the electric vehicle 40, it sends a command to the ECU 44 to appropriately operate the inverter device 43 of the electric vehicle 40 to convert the AC power from the electrical equipment 20 to DC power. In this way, the EMS 27 controls the inverter device 43 through the ECU 44 and charges the high-voltage battery 41 of the electric vehicle 40 with power from the electrical equipment 20 of the residential building (HM). The power supplied to the electric vehicle 40 from the electrical equipment 20 may be power generated by the solar power generator 29, power from the distribution system 12A, or both. When the EMS 27 supplies power from the electrical equipment 20 to the electric vehicle 40 using only the power generated by the solar power generator 29, it opens the switch 23.

[0153] Furthermore, the EMS 27 may communicate with the PCS 29B of the solar power generator 29 via a transmission line such as a one-to-one communication line to ascertain the surplus power of the solar power generator 29 and charge the high-voltage battery 41 of the electric vehicle 40 with that surplus power. Specifically, if the solar power generator 29 is generating surplus power, or if there is a possibility of surplus power being generated, the EMS 27 may check the charge level of the high-voltage battery 41 by communicating with the ECU 44. If the charge level of the high-voltage battery 41 is relatively small compared to a predetermined standard, the EMS 27 may determine that it is possible to accept the surplus power of the solar power generator 29 and control the inverter device 43 via the ECU 44 to charge the high-voltage battery 41 of the electric vehicle 40 with the surplus power of the solar power generator 29. The charge level of the high-voltage battery 41 being relatively small compared to a predetermined standard means that the charge level of the high-voltage battery 41 is below a predetermined standard, or less than a predetermined standard.

[0154] Surplus power from the solar power generator 29 refers to, for example, the portion of the solar power generator 29's output power that exceeds the sum of the power consumed by the electrical load 21 and the power that the solar power generator 29 can output to the power grid 10. For example, surplus power from the solar power generator 29 may arise during the daytime when the amount of power generated by solar power generators connected to the power grid 10, including the solar power generator 29, is relatively high, due to output curtailment commands to the solar power generator 29 from aggregators, etc., caused by grid congestion. Grid congestion refers to a situation in which the load on the power grid 10 becomes very high, for example, when the amount of power supplied from power sources connected to the power grid 10 by interconnection lines, such as solar power generators, increases, resulting in very little available transmission capacity in at least a part of the transmission grid 11. Furthermore, surplus power from the solar power generator 29 may arise during the daytime when the amount of power generated by the solar power generator 29 increases, and the rate of change of time of the solar power generator 29's output (output fluctuation rate) increases beyond the upper limit specified in the interconnection requirements with the power grid 10.

[0155] Furthermore, the EMS 27 may detect a power shortage in the solar power generator 29 and discharge power from the high-voltage battery 41 of the electric vehicle 40 to the electrical equipment 20 of the residence HM to compensate for the power shortage. Specifically, if a power shortage occurs or is likely to occur in the solar power generator 29, the EMS 27 may determine the charge level of the high-voltage battery 41 by communicating with the ECU 44. If the charge level of the high-voltage battery 41 is relatively large compared to a predetermined standard, the EMS 27 may determine that it is possible to discharge power from the high-voltage battery 41 and discharge power from the high-voltage battery 41 to the electrical equipment 20 of the residence HM by controlling the inverter device 43 via the ECU 44. A charge level of the high-voltage battery 41 being relatively large compared to a predetermined standard means that the charge level of the high-voltage battery 41 is equal to or greater than a predetermined standard. As a result, the power system 1 can use the power from the high-voltage battery 41 to supplement some or all of the power shortage of the solar power generator 29, and consequently, the amount of electricity used from the power grid 10 in the electrical equipment 20 of the residential building can be reduced.

[0156] The power deficit of the solar power generator 29 corresponds, for example, to the portion of the power consumed by the electrical load 21 that exceeds the power that the solar power generator 29 can output. For example, the power deficit of the solar power generator 29 may occur at night when the amount of power generated by the solar power generator 29 is zero and the power consumption of the electrical load 21 increases.

[0157] In this way, the EMS 27 works in conjunction with the ECU 44 of the electric vehicle 40 to absorb the output fluctuations of the solar power generator 29 into the high-voltage battery 41. Therefore, the EMS 27 can effectively utilize the energy of the solar power generator 29. Furthermore, for example, if the use of the electric vehicle 40 is limited to holidays, the electric vehicle 40 may be parked in the parking space of the residential building (HM) and connected to the electrical equipment 20 via the charge / discharge cable 26 for a relatively long period of time. In this case, for example, the capacity of the storage battery installed in the residential building (HM) to absorb the output fluctuations of the solar power generator 29 can be relatively reduced, and as a result, capital investment in the residential building (HM) can be suppressed.

[0158] [Third Example of Power System Operation] A third example of the operation of the power system 1 according to this embodiment will be described with reference to Figure 7.

[0159] Figure 7 is a schematic sequence diagram illustrating a third example of the operation of power system 1. Specifically, it is a schematic sequence diagram illustrating an example of the operation of power system 1 in the second example during a power outage in power grid 10.

[0160] The operation shown in the sequence diagram of Figure 7 is performed when the power system 1 has a function to detect the isolated operation of the power supply unit 22.

[0161] In this example, the solar power generator 29 (specifically, PCS 29B) satisfies the interconnection requirements for the power grid 10, and the power system 1 has a function to detect the isolated operation of the power supply unit 22. Therefore, assuming that the electric vehicle 40 satisfies other interconnection requirements, and that the power grid 10 is in a normal state and the switch 23 is ON, power can be supplied from the electric vehicle 40 (specifically, the high-voltage battery 41) to the electrical equipment 20 (specifically, the power supply unit 22) (in other words, it is permissible).

[0162] As shown in Figure 7, under normal conditions of the power system 10, the power supply unit 22 of the electrical equipment 20 receives power from the solar power generator 29 in addition to the power supply from the power system 10 (step S302), and the electrical load 21 of the electrical equipment 20 operates with power supplied from the power supply unit 22 (step S304).

[0163] Furthermore, when the power system 10 is functioning normally, the inverter device 43 is in standby mode under the control of the ECU 44, and the high-voltage battery 41 has stopped charging and discharging (step S306).

[0164] In this example, as will be described later, a power outage in the power system 10 occurs when the inverter device 43 is in standby mode. However, it is also possible that a power outage in the power system 10 may occur when the inverter device 43 is in a charging state or an auxiliary power state. In other words, in step S306, the inverter device 43 may be in a charging state or an auxiliary power state under the control of the ECU 44. In this case, in step S314, described later, the inverter device 43 transitions from the charging state or auxiliary power state to the main power state.

[0165] Steps S308, S310, and S312 are the same as the processes in steps S208, S210, and S212 in Figure 5, so their explanation is omitted.

[0166] In response to the ECU 44 receiving an isolated operation detection signal, the inverter device 43 of the electric vehicle 40 transitions from standby state to main power state under the control of the ECU 44 (step S314).

[0167] Furthermore, if the inverter device 43 has the function of the predetermined power source (for example, a virtual synchronous generator), the processing in steps S310 and S314 may be performed in a different order or simultaneously in parallel. Specifically, after the independent operation of the power supply unit 22 is detected in step S308, the processing in step S312 may be executed, and after the inverter device 43 of the electric vehicle 40 transitions from a standby state to a main power state by the processing in step S314, the processing in step S310 may be executed, and the connection between the power distribution system 12A and the power supply unit 22 may transition from a connected state to a disconnected state. In this case, since the inverter device 43 functions as the predetermined power source, voltage can be applied to the electrical load 21 even during the period from the occurrence of a power outage in the power system 10 until the switch 23 transitions to a disconnected state. Moreover, as described above, the switch 23 may be a semiconductor switch. In this case, the power system 10 experiencing a power outage and the inverter device 43 can be quickly disconnected. This allows the power supply from the inverter device 43 to the point of abnormality in the power system 10 to be quickly cut off. In other words, the inverter device 43 can be switched to the main power state without any interruption.

[0168] Then, the high-voltage battery 41 discharges to the electrical equipment 20 through the inverter device 43, which is in the main power state (step S316).

[0169] As a result, the power supply unit 22 of the electrical equipment 20 can receive power from the high-voltage battery 41 of the electric vehicle 40 through the inverter device 43 (step S318).

[0170] Therefore, the electrical load 21 of the electrical equipment 20 and the PCS 29B of the solar power generator 29 can continue to operate by receiving power from the power supply unit 22 (step S320).

[0171] As described above, when the power system 10 is functioning normally and power is supplied from the power system 10 to the power supply unit 22, the PCS29B operates as a current source to follow the voltage and frequency of the power system 10. Therefore, if a power outage occurs in the power system 10 and the switch 23 is switched from ON (closed) to OFF (open), a large fluctuation occurs in the voltage and frequency of the power supply unit 22, and the PCS29B cannot follow this fluctuation. For this reason, it may become necessary to shut down the PCS29B.

[0172] In contrast, in this example, when a power outage occurs in the power system 10, the inverter device 43 functions as the main power source for the power supply unit 22, suppressing fluctuations in the voltage and frequency of the power supply unit 22. Therefore, there is no need to stop the PCS 29B, and the PCS 29B can continue to operate by synchronizing with the voltage and frequency of the inverter device 43. For example, even if the remaining capacity of the high-voltage battery 41 of the electric vehicle 40 is low, the electric load 21 can continue to operate without stopping, using the power from the solar power generator 29.

[0173] Furthermore, while it may be possible to supply power from the solar power generator 29 to the electrical load 21 through the independent operation of PCS29B, in this case, PCS29B must be stopped once before starting independent operation. Therefore, it takes time before power supply from the solar power generator 29 to the electrical load 21 can be resumed.

[0174] Steps S322, S324, S326, S328, S330, and S332 are the same as the processes in steps S222, S224, S226, S228, S230, and S232 in Figure 2, so their explanation is omitted.

[0175] The PCS 29B of the solar power generator 29 can continue operating and supplying power to the electrical load 21 by synchronizing with the voltage and frequency of the power system 10 after the switch 23 is turned from OFF to ON (step S328).

[0176] [Configuration of the Third Example of the Power System] The configuration of the third example of the power system 1 according to this embodiment will be described in detail with reference to Figures 8 to 10.

[0177] In the following examples, components that are the same as or correspond to those in the first example (Figure 1) and second example (Figure 6) of the power system 1 described above are denoted by the same reference numerals. The explanation will focus on the parts that differ from the first and second examples, and the explanation of parts that are the same as or correspond to those in the first and second examples may be omitted.

[0178] Figure 8 shows the configuration of the third example of power system 1. Figure 9 shows the third example of the circuit configuration for power exchange between the electrical equipment 20 of the residential building (HM) and the electric vehicle 40. Figure 10 shows the fourth example of the circuit configuration for power exchange between the electrical equipment 20 of the residential building (HM) and the electric vehicle 40.

[0179] The power system 1 in this example differs from the first example (Figure 1) and the second example (Figure 6) described above mainly in that the electrical equipment 20 of the residential building (HM) and the electric vehicle 40 are electrically connected by a contactless power supply device (WPS).

[0180] <Electrical Equipment> Unlike the first and second examples described above, the electrical equipment 20 includes an electrical load 21, a power supply unit 22, a switch 23, a switch 24, a circuit breaker 25, an EMS 27, and a power transmission and reception device 28.

[0181] Unlike the first and second examples described above, the power supply unit 22 includes power lines PL21 to PL24 and a power converter 22D.

[0182] The power converter 22D is installed on the power line PL22 and exchanges AC power between the power transmission / reception device 28 side of power line PL22 and the power lines PL21 and PL23 sides. The power converter 22D functions as a frequency converter that exchanges power between the AC on the power transmission / reception device 28 side, which may become high frequency due to contactless power transmission by the contactless power supply device WPS, and the AC on the commercial frequency power line PL21 side supplied from the power distribution system 12A. The power converter 22D may also be equipment that satisfies the interconnection requirements for the power system 10 and has received the prescribed certification. As a result, the power converter 22D can output power supplied from the electric vehicle 40 via the contactless power supply device WPS to the power system 10 via power lines PL22 and PL21.

[0183] The power transmission and reception device 28 is installed at the end of the power line PL22 and is an interface for contactless power exchange with the electric vehicle 40 under the control of the EMS27. The power transmission and reception device 28, together with the power transmission and reception device 48 mounted on the electric vehicle 40, constitutes a contactless power supply device WPS. This allows, for example, residents of the residential building (HM) and users of the electric vehicle 40 to exchange power with each other without having to perform the work of connecting cables or the like between the electrical equipment 20 of the residential building (HM) and the electric vehicle 40. Therefore, the contactless power supply device WPS can improve convenience for residents of the residential building (HM) and users of the electric vehicle 40.

[0184] The WPS (Wall Power Supply) is a non-contact power supply device that allows for bidirectional contactless (wireless) power exchange between the power transmitting / receiving devices 28 and 48, with either the transmitting side being the transmitting side and the other the receiving side. The WPS can achieve contactless power exchange between the power transmitting / receiving devices 28 and 48 using any known method. For example, the WPS is a transformer that transmits power from the primary side (transmitting side) to the secondary side (receiving side) by electromagnetic induction corresponding to the magnetic coupling between the coils of the respective power transmitting / receiving devices 28 and 48. Alternatively, the WPS can use magnetic resonance to transmit power from the transmitting coil to the receiving coil of the power transmitting / receiving device 28 or 48. This allows for a longer distance over which power can be transmitted between the power transmitting / receiving devices 28 and 48 compared to power transmission by normal electromagnetic induction. Therefore, the constraints on the positional relationship between the power transmission / receiving device 28 and the power transmission / receiving device 48 are relatively relaxed, and as a result, the convenience of residents of the residential building (HM) and users of the electric vehicle (40) can be improved.

[0185] <Electric Vehicle> The electric vehicle 40 includes power lines PL41 to PL45, a high-voltage battery 41, an electric motor 42, an inverter device 43, an ECU 44, a switch 47, a power transmission and reception device 48, and a charging port 46.

[0186] Power line PL43 is an AC power line connecting the motor 42 and the power transmission / reception device 48. Specifically, power line PL43 connects the neutral point 43NP of the armature 42A of the motor 42 to one end of the power transmission / reception device 48.

[0187] Power line PL44 is a reference potential line that connects the one end of power line PL43 in the power transmission / reception device 48 to which power line PL43 is connected, and the other end opposite to it, to the DC link 43DC of the inverter device 43.

[0188] For example, as shown in Figure 9, a DC cut-off capacitor 49 is provided on the power line PL44. This removes the DC component from the AC at the neutral point 43NP of the armature 42A that occurs between the power line PL44, which acts as a reference potential line, when power is exchanged between the electrical equipment 20 of the residence HM and the electric vehicle 40, thereby generating an AC voltage of a predetermined frequency that does not contain a DC component. The predetermined frequency is a frequency suitable for driving the contactless power supply device WPS, and is set to, for example, 10 kHz or higher.

[0189] Furthermore, as shown in Figure 10, the power line PL44 may be connected to the midpoint of the balanced smoothing capacitors 43c1 and 43c2 in the DC link 43DC. This allows the smoothing capacitors 43c1 and 43c2 to perform the same function as the DC cut-off capacitor 49. As a result, the increase in cost and weight of the electric vehicle 40 can be suppressed, as well as the overall cost of the electrical equipment 20 of the residence HM and the power supply system of the electric vehicle 40.

[0190] Similar to the first example described above, the inverter device 43 drives the motor 42 by converting the DC supplied from the high-voltage battery 41 through the power line PL 41 into a three-phase AC of a predetermined voltage and frequency and outputting it to the power line PL 42. Specifically, as shown in Figures 9 and 10, the inverter device 43 includes a smoothing circuit 43A and an inverter circuit 43B, similar to the first example described above. The inverter device 43 is also equipped with sensors capable of measuring various states such as current, voltage, and temperature, similar to the first example described above.

[0191] The smoothing circuit 43A, like the first example described above, suppresses and smooths the pulsations of the DC output from the high-voltage battery 41 and the DC output from the inverter circuit 43B. The smoothing circuit 43A, like the first example described above, includes a smoothing capacitor 43c of the DC link 43DC. For example, as shown in Figure 9, the smoothing capacitor 43c is provided in the power line between the positive line 43P and the negative line 43N of the DC link 43DC. The smoothing capacitor 43c may consist of one capacitor or multiple capacitors. For example, as shown in Figure 10, the smoothing capacitor 43c is composed of multiple (two in this example) smoothing capacitors 43c1 and 43c2 connected in series between the positive line 43P and the negative line 43N. This produces the same function and effect as the first example described above.

[0192] The inverter circuit 43B has the positive line 43P and negative line 43N of the DC link 43DC connected to one end, and the U-phase line PL42u, V-phase line PL42v, and W-phase line PL42w of the three-phase AC power line PL42 connected to the other end.

[0193] For example, as shown in Figures 9 and 10, the inverter circuit 43B includes six semiconductor switches 43sw, similar to the first example described above. Specifically, the inverter circuit 43B includes a bridge circuit in which three sets of switch legs, each consisting of two semiconductor switches 43sw constituting the upper and lower arms connected in series, are connected in parallel between the positive line 43P and the negative line 43N. Then, U-phase line PL42u, V-phase line PL42v, and W-phase line PL42w are drawn out from the midpoints of the three sets of upper and lower arms of the bridge circuit and connected to the U-phase winding 42u, V-phase winding 42v, and W-phase winding 42w of the armature 42A, respectively. In addition, a recirculating diode 43d may be connected in parallel to each of the six semiconductor switches 43sw.

[0194] The switch 47 is installed on the power line PL 43 and is configured to electrically open and close the power line PL 43 under the control of the ECU 44. For example, the switch 47 is set to the open state when the electric vehicle 40 is in operation and to the closed state when the electric vehicle 40 is stopped. This allows the power supply from the inverter device 43 and the armature 42A of the electric motor 42 to the power transmission and reception device 48 to be cut off when the electric vehicle 40 is in operation.

[0195] The power transmission and reception device 48 has one end connected to the power line PL43 and the other end connected to the power line PL44, and is an interface for contactless power exchange with the electrical equipment 20 of the residential building (HM) under the control of the ECU 44. As described above, the power transmission and reception device 48, together with the power transmission and reception device 28 of the electrical equipment 20 of the residential building (HM), constitutes a contactless power supply device (WPS).

[0196] For example, the power transmission / reception device 28 is installed on the ground in the parking space of the residential building (HM), and the power transmission / reception device 48 is installed on the underside of the floor of the electric vehicle 40. This allows for contactless power exchange between the power transmission / reception device 28 and the power transmission / reception device 48 when the electric vehicle 40 is parked in the parking space such that the power transmission / reception device 48 on the underside of the floor of the electric vehicle 40 is positioned above the power transmission / reception device 28 on the ground.

[0197] Furthermore, the power transmission / receiving device 28 is normally covered on its surface by a protective member, and may be movable so that the protective member is released from covering the power transmission / receiving device 28 when power is exchanged with the power transmission / receiving device 28, exposing the power transmission / receiving device 28 upwards. Similarly, the power transmission / receiving device 48 is covered on its surface (underside) by a protective member when the electric vehicle 40 is in operation, and may be movable so that the protective member is released from covering the power transmission / receiving device 48 when power is exchanged with the power transmission / receiving device 28, exposing the power transmission / receiving device 48 downwards. This makes it possible to more appropriately achieve contactless power exchange between the power transmission / receiving device 28 and the power transmission / receiving device 48 while suppressing contamination, malfunction of the power transmission / receiving device 28 and the power transmission / receiving device 48, and preventing electric shock due to exposure of the power transmission / receiving device 28 and the power transmission / receiving device 48.

[0198] For example, the EMS 27 may control the position of the protective member of the power transmission / receiving device 28 so that the upper part of the power transmission / receiving device 28 is exposed, if the relative positions of the power transmission / receiving device 28 and the power transmission / receiving device 48 are within a predetermined range in which power can be transmitted and received between them. Similarly, the ECU 44 may control the position of the protective member of the power transmission / receiving device 48 so that the lower part of the power transmission / receiving device 48 is exposed, if the relative positions of the power transmission / receiving device 28 and the power transmission / receiving device 48 are within a predetermined range in which power can be transmitted and received between them. In this case, the relative positions of the power transmission / receiving device 28 and the power transmission / receiving device 48 may be determined by the EMS 27 and the ECU 44 individually, or one of them may determine it and the other may control the position of the protective member according to a command from the other. The control of the position of the protective member may be performed, for example, in response to a request from a resident of a house HM or a user of an electric vehicle 40. Residents of the residential building (HM) and users of the electric vehicle 40 can communicate their requests to the EMS 27 or ECU 44 by performing predetermined operations on an operating unit located in the parking space of the residential building (HM) or by performing predetermined operations on a portable terminal capable of wireless communication with the EMS 27 or ECU 44. The operating terminal may be a dedicated terminal or a general-purpose portable terminal such as a smartphone. Furthermore, the position control of the protective member may be performed automatically according to the conditions of the positional relationship between the power transmission / reception device 28 and the power transmission / reception device 48. This eliminates the need for work by residents of the residential building (HM) and users of the electric vehicle 40, further improving convenience for them.

[0199] [Configuration of other power system examples] The configuration of other power system 1 examples is described below.

[0200] The configurations of the first to third examples of power system 1 described above may be modified or changed as appropriate. Hereinafter, examples obtained by modifying or changing the first to third examples of power system 1 described above will be conveniently referred to as "modified versions".

[0201] For example, the configuration of the third example of the power system 1 described above may include a solar power generator 29 or other types of power sources, similar to the second example described above.

[0202] Furthermore, in the first and second examples of the power system 1 described above, and in their modified forms, the isolation transformer 22A may be omitted.

[0203] Furthermore, in the first to third examples of the power system 1, the electrical equipment 20 may be configured to be electrically connected in parallel with a plurality of electric vehicles 40, and may be able to exchange power with each of the electric vehicles 40.

[0204] More specifically, the electrical equipment 20 has multiple charge / discharge cables 26 or multiple power transmission / receiving devices 28 connected in parallel to the power line PL 22 so that multiple electric vehicles 40 can be connected in parallel. By connecting multiple electric vehicles 40 through the multiple charge / discharge cables 26 or multiple power transmission / receiving devices 28, the electrical equipment 20 can be electrically connected in parallel to multiple electric vehicles 40 and can exchange power with each electric vehicle 40. Furthermore, if the inverter devices 43 of the multiple electric vehicles 40 have the function of the predetermined power source (for example, a virtual synchronous generator), parallel operation can be continued even if the number of electric vehicles 40 exchanging power with the electrical equipment 20 changes. In other words, even if the number of electric vehicles 40 electrically connected in parallel to the electrical equipment 20 changes and is updated due to the entry and exit of parked electric vehicles 40, parallel operation regarding the exchange of power between the multiple electric vehicles 40 and the electrical equipment 20 can be continued.

[0205] Furthermore, in the first to third examples of power system 1 and their variations, instead of the inverter device 43, a dedicated power converter for charging and discharging the high-voltage battery 41 in relation to the electrical equipment 20 (specifically, the power supply unit 22) may be provided in the electric vehicle 40. In this case, inside the electric vehicle 40, the power converter dedicated to charging and discharging has its DC input / output section electrically connected to the high-voltage battery 41, and its AC input / output section electrically connected to the charging / discharging port 45 and the power transmission / receiving device 48. Also, similar to the inverter device 43 described above, the power converter dedicated to charging and discharging operates to function as a predetermined power source that suppresses fluctuations in the voltage and frequency of the power supply unit 22 when the electric vehicle 40 is stopped, the electrical equipment 20 and the electric vehicle 40 are electrically connected, and there is a power outage in the power system 10.

[0206] [Other Examples of Power System Operation] The first to third examples of power system 1 operation described above may be modified or altered as appropriate. Hereinafter, examples obtained by modifying or altering the first to third examples of power system 1 operation described above will be conveniently referred to as "modified examples".

[0207] For example, the first and second examples of the operation of the power system 1 described above may be applied as the operation of the third example of the power system 1 described above.

[0208] Furthermore, the third example of the operation of the power system 1 described above may also be applied as a modified version of the operation of the third example of the power system 1 described above.

[0209] [Operation] The operation of the power system, power converter, control device, and control method according to this embodiment will be described.

[0210] In a first aspect of this embodiment, a power system is provided comprising a power storage device, an electric motor, a first power conversion device, an electrical load, a power supply unit, a power connection unit, and a switch. The power conversion system is, for example, the power system 1 described above. The power storage device is, for example, the high-voltage battery 41 described above. The electric motor is, for example, the electric motor 42 described above. The first power conversion device is, for example, the inverter device 43 described above. Alternatively, the first power conversion device may be a dedicated power conversion device for charging and discharging the high-voltage battery 41 with the electrical equipment 20 (specifically, the power supply unit 22) described above. The electrical load is, for example, the electrical load 21 described above. The power supply unit is, for example, the power supply unit 22 described above. The power connection unit is, for example, the power connection unit PC described above or the contactless power supply device WPS described above. The switch is, for example, the switch 23 described above. Specifically, the power storage device is mounted on a vehicle. The vehicle is, for example, the electric vehicle 40 described above. Furthermore, the electric motor is mounted on the vehicle and drives the vehicle's drive wheels with the power from the energy storage device. The first power converter is mounted on the vehicle and electrically connected to the energy storage device. The electrical load is provided in a dwelling or facility. The dwelling is, for example, the HM described above. The facility is, for example, facility FC described above. The power supply unit is provided in the dwelling or facility and is electrically connected to an AC power system to supply power to the electrical load. The AC power system is, for example, the power system 10 described above. The power connection unit electrically connects the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit. The switch switches between an electrical connection state and a disconnected state between the power supply unit and the AC power system. The switch is switched to the disconnected state in the event of a power outage in the AC power system. Furthermore, when the power supply unit and the vehicle are electrically connected by the power connection unit, the first power converter operates to function as a predetermined power source for the power supply unit using the power of the energy storage device during a power outage in the AC power system.

[0211] This allows the power system to autonomously operate the first power converter during an AC power grid outage, enabling it to power electrical loads by supplying power from the vehicle to the ground (residential or facility side). Therefore, the power system can effectively utilize the power from the vehicle's energy storage device as a distributed power source during an AC power grid outage.

[0212] Furthermore, in a second aspect of this embodiment, based on the first aspect described above, the predetermined power supply may operate in such a way as to suppress fluctuations in the voltage and frequency of the power supply unit.

[0213] As a result, the first power converter can immediately begin independent operation while suppressing fluctuations in the voltage and frequency of the power supply section in the event of a power outage in the AC power system. Therefore, the power conversion system can continue the operation of electrical loads in the event of a power outage in the AC power system.

[0214] Furthermore, in a third aspect of this embodiment, based on the second aspect described above, the predetermined power supply may be at least one of the following: a first power supply that maintains a constant voltage and frequency; a second power supply that exerts a pseudo-inertial force against fluctuations in voltage or frequency; a third power supply corresponding to a virtual synchronous generator; a fourth power supply having grid-forming characteristics that generate a reference voltage and frequency that other power supplies can follow; or a fifth power supply that suppresses fluctuations in voltage and frequency, based on grid-following characteristics that follow the reference voltage and frequency of other power supplies. The first power supply is, for example, the constant voltage constant frequency power supply (CVCF power supply) described above. The second power supply is, for example, the virtual inertial power supply described above. The fourth power supply is a GFM power supply. The fifth power supply is, for example, the stabilized GFL power supply described above.

[0215] This allows the power conversion system to immediately begin autonomous operation of the first power converter.

[0216] Furthermore, in a fourth aspect of this embodiment, the electric motor and the power connection unit may be electrically connected, based on any one of the first to third aspects described above. The first power converter may drive the electric motor using the power of the energy storage device when the vehicle is running, and may also supply power to the power supply unit using the power of the energy storage device when the power connection unit is electrically connected to the vehicle and the power supply unit.

[0217] This allows the power system to use a single first power converter for both the power converter for driving the vehicle and the power converter for charging and discharging the energy storage device between the vehicle and the ground. As a result, the power system can suppress increases in vehicle costs. Furthermore, the power converter for driving the vehicle is usually capable of handling large currents and has ample capacity from the perspective of charging and discharging with the ground. Therefore, by having the power converter for driving the vehicle also be used for charging and discharging the energy storage device between the vehicle and the ground, the power system can withstand, for example, the inrush current from the vehicle to the ground during a power outage in the AC power system.

[0218] Furthermore, in a fifth aspect of this embodiment, based on any one of the first to fourth aspects described above, the power system may include a DC power supply and a second power converter. The DC power supply is, for example, the solar panel 29A described above. The second power converter is, for example, the PCS 29B described above. Specifically, the DC power supply may be provided in the residence or facility. The second power converter may be provided in the residence or facility and operate as a current source for the power supply unit using the power from the DC power supply.

[0219] As a result, in the event of a power outage in the AC power grid, the power system can continue operating the second power converter as a current source by initiating the independent operation of the first power converter. Therefore, the power system can continue supplying power from the DC power source to the electrical load in the event of a power outage in the AC power grid.

[0220] Furthermore, in a sixth aspect of this embodiment, based on any one of the first to fifth aspects described above, the power system may include an islanding detection unit for detecting islanding of the power supply unit. The islanding detection unit is, for example, the EMS27 described above. Specifically, when islanding is detected by the islanding detection unit, the power system may switch the switch from a connected state to a disconnected state, and the first power converter may switch to a state in which it operates as the predetermined power source for the power supply unit.

[0221] This allows the power system to continue operating electrical loads without interrupting the power supply from the power source to the loads in the event of a power outage in the AC power grid.

[0222] Furthermore, in the seventh aspect of this embodiment, based on any one of the first to sixth aspects described above, the energy storage device, the electric motor, and the first power converter may be mounted on each of the multiple vehicles. The power connection section may be provided in multiple locations so that each of the multiple vehicles' first power converters can be electrically connected to the power supply section.

[0223] This allows the power system to exchange power between the energy storage devices of multiple vehicles and the ground. Therefore, in the event of a power outage in the AC power grid, the power system can effectively utilize the power from the energy storage devices of each of the vehicles.

[0224] Furthermore, in an eighth aspect of this embodiment, a power converter may be provided, mounted on the vehicle together with a power storage device and an electric motor that drives the vehicle's drive wheels with the power from the power storage device. The power converter is, for example, the inverter device 43 described above. The power converter may also be a dedicated power converter for charging and discharging the high-voltage battery 41 with the electrical equipment 20 (specifically, the power supply unit 22) described above. The vehicle is, for example, the electric vehicle 40 described above. The power storage device is, for example, the high-voltage battery 41 described above. The electric motor is, for example, the electric motor 42 described above. Specifically, the power converter may be installed in a dwelling or facility and electrically connected to an AC power system via a switch that switches between an electrical connection state and a disconnected state, and may be electrically connectable through a power connection unit to a power supply unit that supplies power to the electrical load of the dwelling or facility. The dwelling is, for example, the dwelling HM described above. The facility is, for example, the facility FC described above. The switch is, for example, the switch 23 described above. The AC power system is, for example, the power system 10 described above. The electrical load is, for example, the electrical load 21 described above. The power supply unit is, for example, the power supply unit 22 described above. The power connection unit is, for example, the power connection unit PC described above or the contactless power supply device WPS described above. When the power converter is electrically connected to the power supply unit by the power connection unit, it operates to function as a predetermined power source for the power supply unit using the power of the energy storage device in the event of a power outage in the AC power system, thereby achieving the same effects and benefits as the power system of the first embodiment described above.

[0225] Furthermore, with respect to the power conversion device, an embodiment similar to the second to seventh embodiments of the power system described above can be realized, based on the eighth embodiment described above.

[0226] As a result, the power conversion device performs the same functions and effects as the power systems of the second to seventh embodiments described above.

[0227] Furthermore, in a ninth aspect of this embodiment, a control device for controlling a power system is provided, which includes: a power storage device mounted on a vehicle; an electric motor mounted on the vehicle that drives the vehicle's drive wheels with power from the power storage device; a first power converter mounted on the vehicle and electrically connected to the power storage device; an electrical load provided in a dwelling or facility; a power supply unit provided in the dwelling or facility and electrically connected to an AC power system to supply power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch for switching between an electrical connection state and a disconnection state between the power supply unit and the AC power system. The control device is, for example, the EMS 27 described above. The vehicle is, for example, the electric vehicle 40 described above. The power storage device is, for example, the high-voltage battery 41 described above. The electric motor is, for example, the electric motor 42 described above. The first power converter is, for example, the inverter device 43 described above. Furthermore, the first power converter may be a dedicated power converter for charging and discharging the high-voltage battery 41 with the electrical equipment 20 (specifically, the power supply unit 22) as described above. The residence is, for example, the residence HM described above. The facility is, for example, the facility FC described above. The electrical load is, for example, the electrical load 21 described above. The AC power system is, for example, the power system 10 described above. The power supply unit is, for example, the power supply unit 22 described above. The power connection unit is, for example, the power connection unit PC described above or the contactless power supply device WPS described above. The switch is, for example, the switch 23 described above. The power system is, for example, the power system 1 described above. Specifically, the control device may switch the switch to the off state in the event of a power outage in the AC power system. When the power supply unit and the first power converter are electrically connected by the power connection unit, the control device may operate the first power converter to function as a predetermined power source for the power supply unit using the power of the energy storage device in the event of a power outage in the AC power system.

[0228] As a result, the control device performs the same functions and effects as the power system of the first embodiment described above.

[0229] Furthermore, with respect to the control device, an embodiment similar to the second to seventh embodiments of the power system described above can be realized, based on the ninth embodiment described above.

[0230] As a result, the control device performs the same functions and effects as the power systems of the second to seventh embodiments described above.

[0231] Furthermore, in a tenth aspect of this embodiment, a control method may be provided for controlling a power system having: a power storage device mounted on a vehicle; an electric motor mounted on the vehicle that drives the vehicle's drive wheels with power from the power storage device; a first power converter mounted on the vehicle and electrically connected to the power storage device; an electrical load provided in a dwelling or facility; a power supply unit provided in the dwelling or facility and electrically connected to an AC power system to supply power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch for switching between an electrical connection state and a disconnection state between the power supply unit and the AC power system. The vehicle is, for example, the electric vehicle 40 described above. The power storage device is, for example, the high-voltage battery 41 described above. The electric motor is, for example, the electric motor 42 described above. The first power converter is, for example, the inverter device 43 described above. Furthermore, the first power converter may be a dedicated power converter for charging and discharging the high-voltage battery 41 with the electrical equipment 20 (specifically, the power supply unit 22) as described above. The residence is, for example, the residence HM described above. The facility is, for example, the facility FC described above. The electrical load is, for example, the electrical load 21 described above. The AC power system is, for example, the power system 10 described above. The power supply unit is, for example, the power supply unit 22 described above. The power connection unit is, for example, the power connection unit PC described above or the contactless power supply device WPS described above. The switch is, for example, the switch 23 described above. The power system is, for example, the power system 1 described above. Specifically, in the control method, the switch may be switched to the off state in the event of a power outage in the AC power system. Furthermore, in the control method described above, if the power supply unit and the first power converter are electrically connected by the power connection unit, the first power converter may be operated to function as a predetermined power source for the power supply unit using the power of the energy storage device in the event of a power outage in the AC power system.

[0232] As a result, the control method of this embodiment produces the same functions and effects as the power system of the first embodiment described above.

[0233] Furthermore, regarding the control method, based on the tenth embodiment described above, an embodiment similar to the second to seventh embodiments for the power system described above can be realized.

[0234] As a result, the control method of this embodiment produces the same functions and effects as the power systems of the second to seventh embodiments described above.

[0235] Although embodiments have been described in detail above, this disclosure is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist described in the claims.

[0236] Finally, this application claims priority based on Japanese Patent Application No. 2025-050768, filed on 25 March 2025, and the entire contents of the Japanese Patent Application are incorporated herein by reference.

[0237] 1 Power System 10 Power System 11 Transmission System 12 Distribution System 12A Distribution System 12B Distribution System 20 Electrical Equipment 21 Electrical Load 22 Power Supply Unit 22A Isolation Transformer 22B Filter Capacitor 22C DC Cut-off Capacitor 22D Power Converter 23 Switch 24 Switch 25 Circuit Breaker 26 Charging / Discharging Cable 26L Power Line 26N Power Line 27 EMS 28 Power Transmission / Receiving Equipment 29 Solar Power Generator 29A Solar Panel 29B PCS 30 Rapid Charger 31 Charging Cable 40 Electric Vehicle 41 High-Voltage Battery 42 Electric Motor 42A Armature 42u U-phase Winding 42v V-phase Winding 42w W-phase Winding 43 Inverter Device 43A Smoothing Circuit 43B Inverter circuit 43c Smoothing capacitor 43c1 Smoothing capacitor 43c2 Smoothing capacitor 43d Recirculation diode 43DC DC link 43N Negative line 43NP Neutral point 43P Positive line 43sw Semiconductor switch 44 ECU 45 Charging / discharging port 46 Charging port 47 Switch 48 Power transmission / reception device 49 DC cut-off capacitor FC Facility HM Residence PC Power connection part PL21 Power line PL22 Power line PL22L Power line PL22N Power line PL23 Power line PL24 Power line PL25 Power line PL41 Power line PL42 Power line PL42u U-phase line PL42v V-phase line PL42w W-phase line PL43 Power line PL44 Power line PL45 Power line WPS Non-contact power supply device

Claims

1. A power system comprising: a power storage device mounted on a vehicle; an electric motor mounted on the vehicle that drives the vehicle's drive wheels with the power of the power storage device; a first power converter mounted on the vehicle and electrically connected to the power storage device; an electrical load provided in a dwelling or facility; a power supply unit provided in the dwelling or facility and electrically connected to an AC power system to supply power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch for switching between an electrical connection state and a disconnection state between the power supply unit and the AC power system, wherein the switch is switched to a disconnection state in the event of a power outage in the AC power system, and the first power converter operates to function as a predetermined power source for the power supply unit using the power of the power storage device when the power supply unit and the vehicle are electrically connected by the power connection unit in the event of a power outage in the AC power system.

2. The power system according to claim 1, wherein the predetermined power supply operates to suppress fluctuations in the voltage and frequency of the power supply unit.

3. The power system according to claim 2, wherein the predetermined power supply is at least one of a first power supply that maintains a constant voltage and frequency, a second power supply that exerts a pseudo-inertial force against fluctuations in voltage or frequency, a third power supply that corresponds to a virtual synchronous generator, a fourth power supply that has grid-forming characteristics that generate a reference voltage and frequency that other power supplies can follow, or a fifth power supply that suppresses fluctuations in voltage and frequency, based on grid-following characteristics that follow the reference voltage and frequency of other power supplies.

4. The power system according to any one of claims 1 to 3, wherein the electric motor and the power connection unit are electrically connected, the first power converter drives the electric motor using the power of the energy storage device when the vehicle is running, and is capable of supplying power to the power supply unit using the power of the energy storage device when the power connection unit is electrically connected to the vehicle and the power supply unit.

5. The power system according to any one of claims 1 to 3, comprising: a DC power supply provided in the residence or facility; and a second power converter provided in the residence or facility, which operates as a current source for the power supply unit using the power of the DC power supply.

6. The power system according to claim 3, further comprising an islanding detection unit for detecting islanding of the power supply unit, wherein when islanding is detected by the islanding detection unit, the switch switches from a connected state to a disconnected state, and the first power converter switches to a state in which it operates as the virtual synchronous generator for the power supply unit.

7. The power system according to any one of claims 1 to 3, wherein the energy storage device, the electric motor, and the first power converter are mounted on each of the plurality of vehicles, and the power connection section is provided in a plurality of units so as to be able to electrically connect each of the first power converters of the plurality of vehicles to the power supply section.

8. A power converter that is mounted on a vehicle together with a power storage device and an electric motor that drives the vehicle's drive wheels with the power of the power storage device, and is installed in a dwelling or facility, and is electrically connected to an AC power system via a switch that switches between an electrical connection state and a disconnected state, and is electrically connectable through a power connection section to a power supply unit that supplies power to the electrical load of the dwelling or facility, and when electrically connected to the power supply unit by the power connection section, operates to function as a predetermined power source for the power supply unit using the power of the power storage device in the event of a power outage in the AC power system.

9. A control device for controlling a power system comprising: an energy storage device mounted on a vehicle; an electric motor mounted on the vehicle that drives the drive wheels of the vehicle with the power of the energy storage device; a first power converter mounted on the vehicle and electrically connected to the energy storage device; an electrical load provided in a dwelling or facility; a power supply unit provided in the dwelling or facility and electrically connected to an AC power system to supply power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch for switching between an electrical connection state and a disconnected state between the power supply unit and the AC power system, wherein, in the event of a power outage in the AC power system, the switch is switched to a disconnected state, and, if the power supply unit and the first power converter are electrically connected by the power connection unit, the first power converter is operated to function as a predetermined power source for the power supply unit using the power of the energy storage device in the event of a power outage in the AC power system.

10. A control method for controlling a power system comprising: a power storage device mounted on a vehicle; an electric motor mounted on the vehicle that drives the vehicle's drive wheels with the power of the power storage device; a first power converter mounted on the vehicle and electrically connected to the power storage device; an electrical load provided in a dwelling or facility; a power supply unit provided in the dwelling or facility and electrically connected to an AC power system to supply power to the electrical load; a power connection unit for electrically connecting the power supply unit and the vehicle so that power can be exchanged between the first power converter and the power supply unit; and a switch for switching between an electrical connection state and a disconnected state between the power supply unit and the AC power system, wherein in the event of a power outage in the AC power system, the switch is switched to a disconnected state, and if the power supply unit and the first power converter are electrically connected by the power connection unit, the first power converter is operated to function as a predetermined power source for the power supply unit using the power of the power storage device in the event of a power outage in the AC power system. Control method.

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