Power supply system

Abstract

This system ensures that power can continue to be supplied to the power load even if the power supply from the vehicle is interrupted. [Solution] The controller performs the following steps when power is being supplied from the vehicle (YES in S150) and when a power supply stop command is received (YES in S152): checking the vehicle power supply voltage (S154); maintaining the ON state of the second electromagnetic switch (S158) when the vehicle power supply voltage is greater than a threshold Va (YES in S156); and turning the first electromagnetic switch ON and the second electromagnetic switch OFF (S160) when the vehicle power supply voltage is less than or equal to a threshold Va (NO in S156).

Description

Technical Field

[0001] This disclosure relates to a power supply system.

Background Art

[0002] In a power supply system capable of supplying power from a system power source to a power load of a house, power from a vehicle can mainly be supplied to the power load in an emergency (such as when the system power source fails or when the power of the system power source is in short supply). In addition, it has also been proposed to supply power from a vehicle to a power load in daily use (such as during a time period when the electricity charge of the system power source is high). Japanese Patent Application Laid-Open No. 2019-71721 (Patent Document 1) discloses a power supply system that can utilize the power stored in an electric vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the power supply system as described above, when power supply from the vehicle to the power load is inhibited, for example, when the connector connecting the vehicle and the power load is disconnected while power is being supplied from the vehicle to the power load, the power supply to the power load may be stopped and it may not be possible to continue the power supply.

[0005] This disclosure has been made to solve the above problems, and an object thereof is to provide a power supply system capable of continuing power supply to a power load even when power supply from a vehicle is inhibited.

Means for Solving the Problems

[0006] A power supply system relating to a certain aspect of this disclosure is a power supply system that supplies AC power from a grid power source to a power load in a house. The power supply system comprises a vehicle equipped with a power storage device, a current circuit breaker that receives AC power from the grid power source to the house and interrupts it at least in the event of an overcurrent, a load circuit breaker configured to electrically interrupt the connection between the current circuit breaker and the power load, a first switch configured to switch between electrical connection and interruption between the current circuit breaker and the power load, a second switch provided on a power line branched from the power line between the first switch and the power load and configured to switch between electrical connection and interruption between the power load and the vehicle, and a control device that controls the operation of the first switch and the second switch, respectively. When the control device receives a power supply stop command while power is being supplied from the vehicle, it switches the power source to the power load from the vehicle to the grid power source when the power supply voltage from the vehicle falls below a threshold.

[0007] In this way, when a power supply cut-off command is received, the power supply source to the power load can be switched from the vehicle to the grid power supply when the power supply voltage from the vehicle falls below a threshold, so that power can be supplied to the power load even if a connector is disconnected or for other reasons. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a power supply system that can continue to supply power to a power load even when the power supply from the vehicle is interrupted. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of the configuration of the power supply system according to this embodiment. [Figure 2] This is a flowchart showing an example of the control process for an electromagnetic switch. [Figure 3] This flowchart shows an example of the control process for an electromagnetic switch while it is being powered. [Figure 4] This figure shows an example of the configuration of a modified power supply system. [Figure 5]This figure shows another example of the configuration of a modified power supply system. [Figure 6] This flowchart shows an example of the control process for an electromagnetic switch related to a modified example. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0011] Figure 1 shows an example of the configuration of a power supply system according to this embodiment. The power supply system 101 supplies power from the grid power source 900 to the loads of the house 101A. The house 101A is typically a residential building such as a house. However, the house 101A may include non-residential buildings, buildings, and buildings housing equipment. The loads are various electrical devices and are located inside (indoors) or outside (outdoors) the house 101A.

[0012] The power supply system 101 includes a ground fault circuit breaker 1, overcurrent circuit breakers 111-113, 211, 212, and a power supply device 3. The number of overcurrent circuit breakers is not particularly limited.

[0013] Earth leakage circuit breaker 1 receives AC power from the grid power supply 900 to the house 101A. Earth leakage circuit breaker 1 is connected to circuit (power line) PL1 for transmitting AC 100V AC power and circuit PL2 for transmitting AC 200V AC power. Earth leakage circuit breaker 1 electrically interrupts the grid power supply 900 and circuits PL1 and PL2 when an earth leakage current or overcurrent is detected. Earth leakage circuit breaker 1 corresponds to a "current circuit breaker". Earth leakage circuit breaker 1 only needs to be configured to interrupt the current when an overcurrent is detected, and an overcurrent breaker may be used instead of earth leakage circuit breaker 1.

[0014] Overcurrent breakers 111-113 are electrically connected to circuit PL1 for AC100V. For example, house 101A includes multiple rooms, with loads 121, 122, and 123 provided in each room. Overcurrent breakers 111-113 are provided corresponding to each room in house 101A. When an overcurrent is detected, each of the overcurrent breakers 111-113 is configured to electrically interrupt the circuit between the earth leakage breaker 1 and loads 121-123. Overcurrent breaker 113 corresponds to a "load circuit breaker". Each load corresponds to a "power load".

[0015] The overcurrent breakers 211 and 212 are electrically connected to the AC200V circuit PL2. Overcurrent breakers 211 and 212 are also installed in each room of the house 101A. The overcurrent breakers 211 and 212 are configured to electrically interrupt the circuit between the earth leakage breaker 1 and the loads 221 and 222 when an overcurrent is detected.

[0016] The power supply device 3 is configured to be connected to the vehicle 4 via a power supply cable and a connector 5. The vehicle 4 is an electric vehicle equipped with a traction energy storage device (battery) and capable of exchanging power with the outside of the vehicle, specifically a BEV (Battery Electric Vehicle) or a PHEV (Plug-in Hybrid Electric Vehicle). The vehicle 4 further includes a power converter that converts the DC power of the energy storage device into AC power. The power supply device 3 is configured to supply AC power from the vehicle 4 to the load (load 123 in this example) or to stop supplying power when the vehicle 4 is connected, in response to a control command from the controller 10.

[0017] The power supply system 101 further comprises a controller 10, a first electromagnetic switch 51, and a second electromagnetic switch 52.

[0018] The first electromagnetic switch 51 is configured to be able to switch between electrical connection and disconnection between the leakage breaker 1 and the load 123. Specifically, the first end of the first electromagnetic switch 51 is electrically connected to the circuit PL1 for AC100V. The second end of the first electromagnetic switch 51 is electrically connected to the overcurrent breaker 113. The first electromagnetic switch 51 is configured to switch between electrical connection and disconnection between the leakage breaker 1 and the overcurrent breaker 113 according to a control command from the controller 10.

[0019] The second electromagnetic switch 52 is provided on a power line branched from the power line between the first electromagnetic switch 51 and the overcurrent breaker 113, and is configured to be able to switch between electrical connection and disconnection between the load 123 and the vehicle 4. Specifically, the first end of the second electromagnetic switch 52 is electrically connected to a connection node 54 set between the second end of the first electromagnetic switch 51 and the overcurrent breaker 113. The second end of the second electromagnetic switch 52 is electrically connected to the power supply device 3. Thereby, the second electromagnetic switch 52 is configured to switch between electrical connection and disconnection between the connection node 54 and the power supply device 3 according to a control command from the controller 10. These two electromagnetic switches are also collectively referred to as an "electromagnetic switch".

[0020] The controller 10 is a computer device including a processor 11 and a memory 12, and is, for example, a HEMS (Home Energy Management System) controller. The controller 10 outputs control commands for opening and closing (switching on / off) each of the first electromagnetic switch 51 and the second electromagnetic switch 52. The controller 10 may acquire power information (power trading information, electricity rate information, etc.) of the grid power supply 900 from an energy management server (not shown), and open and close the first electromagnetic switch 51 and the second electromagnetic switch 52 or control the power supply device 3 (that is, supply power from the vehicle 4) according to the acquired power information. The controller 10 corresponds to a "control device".

[0021] The voltage measurement unit 13 measures, for example, the voltage of the power transmitted and received between the utility power supply 900 and the leakage breaker 1, and the voltage of the power transmitted and received between the power supply device 3 and the vehicle 4 and the second electromagnetic switch 52, and transmits the measurement results to the controller 10. The voltage measurement unit 13 measures, for example, the voltage and transmits the absolute value of the measured voltage to the controller 10 as the measurement result.

[0022] Since the phases of the AC power supplied from the utility power supply 900 and the AC power supplied from the vehicle 4 are different, the first electromagnetic switch 51 and the second electromagnetic switch 52 are used to select which of the two AC powers is supplied to the loads 121 to 123.

[0023] FIG. 2 is a flowchart showing an example of the control process of the electromagnetic switch. The process shown in FIG. 2 is executed when a predetermined condition is satisfied (for example, every predetermined period). Each step is realized by software processing by the controller 10 (processor 11), but may also be realized by hardware (electrical circuit) arranged in the controller 10. At the start of a series of processes, it is assumed that the first electromagnetic switch 51 is on (closed) and the second electromagnetic switch 52 is off (open).

[0024] In step (hereinafter, steps are described as S) 100, the controller 10 determines whether the power supply device 3 is connected to the vehicle 4. If the power supply device 3 is connected to the vehicle 4 (YES in S100), the process proceeds to S101. If the power supply device 3 is not connected to the vehicle 4 (NO in S100), the process ends.

[0025] In S101, the controller 10 obtains, for example, the power information of the utility power supply 900 (in this example, the current electricity charge information) from the energy management server.

[0026] In S102, the controller 10 determines whether the current electricity rate obtained in S101 is higher than the reference price (for example, the average price of electricity for that day). If the current electricity rate is higher than the reference price (YES in S102), the process moves to S103.

[0027] In S103, the controller 10 acquires the State of Charge (SOC) of the battery mounted on the vehicle 4 through communication with the vehicle 4. In the vehicle 4, the SOC is estimated using various known methods, such as current integration (Coulomb counting) using detected values ​​of the battery's current, voltage, and temperature, or by estimating the open-circuit voltage (OCV).

[0028] In S104, the controller 10 determines whether the acquired SOC is higher than the required value. The required value is, for example, a value corresponding to the amount of power required for the vehicle 4 to run the following day. The required value may be a predetermined fixed value or a variable value determined according to the usage history of the vehicle 4. If the SOC is higher than the required value (YES in S104), the process moves to S105.

[0029] In S105, controller 10 retrieves information about the electricity charges for the last time vehicle 4 was charged from the energy management server. The process then moves to S106.

[0030] In S106, the controller 10 calculates the difference between the current electricity charge obtained in S101 and the electricity charge from the previous charge obtained in S105, and determines whether the difference is greater than or equal to threshold α. If the difference is greater than threshold α (YES in S106), the process moves to S107. If the difference is less than or equal to threshold α (NO in S106), the process moves to S109. In this embodiment, threshold α is a positive value, but threshold α may also be 0. In this embodiment, an example of calculating the difference is shown, but instead of the difference, for example, the controller may determine whether the ratio of the electricity charge b at the time of charging to the current electricity charge a (b / a) is greater than or equal to threshold α. Threshold α may be set, for example, so that the user can earn a profit.

[0031] In S105, information on the electricity cost during the previous charge was obtained. However, if, for example, the power currently stored in vehicle 4 was accumulated through multiple past charges, information on the average electricity cost over those multiple charges may also be obtained.

[0032] In S107, the controller 10 turns off the first electromagnetic switch 51 and turns on the second electromagnetic switch 52. The process then proceeds to S108.

[0033] In S108, the controller 10 controls the power supply device 3 so that power is supplied from the vehicle 4 to the load 123. After that, the process returns to S103. Note that if power is supplied from the vehicle 4, the SOC will decrease over time. Therefore, if the SOC falls below the required value (NO in S104), the process moves to S109.

[0034] In S109, the controller 10 controls the power supply device 3 to terminate the power supply from the vehicle 4 to the load 123. The process then moves to S110.

[0035] In S110, the controller 10 turns on the first electromagnetic switch 51 and turns off the second electromagnetic switch 52. The process is then terminated. If an additional charging device is provided, the charging device may be controlled so that the energy storage device mounted on the vehicle 4 is charged when the electricity price is below the standard price (NO in S102) (S111, S112).

[0036] Figure 2 illustrates an example where subsequent processing changes depending on whether the electricity rate is higher than the standard price. Alternatively, the controller 10 may switch processing depending on whether it is currently nighttime (the time period when nighttime rates apply). This also allows for savings on electricity costs. Alternatively, the controller 10 may switch processing depending on whether it is currently the time of day when the electricity demand of the house 101A is at its peak. By supplying power from the vehicle 4 during the time of peak electricity demand, it becomes possible to meet the peak electricity demand even if the maximum supply current from the grid power source 900 is low, thus allowing for a reduction in the so-called contracted amperage. Therefore, electricity costs can be saved.

[0037] In the power supply system 101 having the above configuration, for example, when the first electromagnetic switch 51 is in the off state and the second electromagnetic switch 52 is in the on state, power is supplied from the vehicle 4 to the load 123. In this case, if the connector 5 is disconnected from the inlet of the vehicle 4, the power supply to the load 123 may be stopped and the power supply may not be able to continue.

[0038] Therefore, in this embodiment, when the controller 10 receives a power supply stop command while power is being supplied from the vehicle 4, it switches the power supply source to the load 123 from the vehicle 4 to the grid power supply 900 when the power supply voltage to the vehicle 4 falls below a threshold.

[0039] In this way, if the connector 5 becomes disconnected from the inlet of the vehicle 4 and the controller 10 receives a power supply stop command from the vehicle 4, the power supply source to the load 123 can be switched from the vehicle 4 to the grid power supply 900 when the power supply voltage from the vehicle 4 falls below a threshold, thus allowing power to be supplied to the load 123 to continue.

[0040] The following describes an example of the process for controlling the electromagnetic switch during power supply, which is performed by the controller 10 in this embodiment, with reference to Figure 3. Figure 3 is a flowchart showing an example of the control process for the electromagnetic switch during power supply. The series of processes shown in this flowchart are executed repeatedly at predetermined intervals. The series of processes assumes that power is being supplied from the vehicle 4 to the load 123, and therefore assumes that the first electromagnetic switch 51 is off (open) and the second electromagnetic switch 52 is on (closed).

[0041] In S150, the controller 10 determines whether or not power is being supplied. The controller 10 may, for example, use the measurement results from the voltage measurement unit 13 to determine whether or not power is being supplied from the vehicle 4 to the load 123. For example, the controller 10 may determine that power is being supplied from the vehicle 4 to the load 123 if the measurement results from the voltage measurement unit 13 (for example, voltage change) indicate that power is not being transmitted from the leakage breaker 1 to the grid power supply 900 (no current is flowing), and that power is being transmitted from the vehicle 4 to the second electromagnetic switch 52 (current is flowing). If it is determined that power is being supplied (YES in S150), the process moves to S152.

[0042] In S152, the controller 10 determines whether or not there is a power supply stop command. The controller 10 determines that there is a power supply stop command if, for example, it receives a power supply stop command from the vehicle 4. In the vehicle 4, a power supply stop command is sent to the controller 10 when the connection of the connector 5 is terminated, for example, when the connector 5 is disconnected from the inlet of the vehicle 4, or when the vehicle 4 receives an operation from the user of the vehicle 4 to stop the power supply. The vehicle 4 (specifically, the vehicle's control device) may determine that the connector 5 has been disconnected from the inlet, for example, when the signal from a switch (not shown) that outputs an ON signal when the connector 5 is attached is switched to an OFF signal. If it is determined that there is a power supply stop command (YES in S152), the process moves to S154.

[0043] In S154, the controller 10 checks the vehicle power supply voltage. The controller 10 obtains the voltage supplied from the vehicle 4 (vehicle power supply voltage) using the measurement results from the voltage measurement unit 13. The process then moves to S156.

[0044] In S156, the controller 10 determines whether the vehicle power supply voltage is greater than the threshold Va. The threshold Va can be any value that allows determination that power supply has been stopped, and may be a predetermined value; it is not particularly limited, but for example, it may be zero. If it is determined that the vehicle power supply voltage is greater than the threshold Va (YES in S156), the process moves to S158.

[0045] In S158, the controller 10 maintains the ON state of the second electromagnetic switch 52. At this time, the controller 10 also maintains the OFF state of the first electromagnetic switch 51. Therefore, power supply from the vehicle 4 to the load 123 continues. The process then returns to S154. On the other hand, if it is determined that the vehicle power supply voltage is below the threshold Va (NO in S156), the process moves to S160.

[0046] In S160, the controller 10 controls the first electromagnetic switch 51 and the second electromagnetic switch 52 so that the first electromagnetic switch 51 is turned on and the second electromagnetic switch 52 is turned off. The process is then terminated.

[0047] The operation of the power supply system 101 according to this embodiment, based on the structure and flowchart described above, will now be explained. For example, consider a case where a connector 5 is connected to the inlet of a vehicle 4, and power is supplied from the battery of the vehicle 4 to the load 123 via the power supply device 3, the second electromagnetic switch 52, and the overcurrent breaker 113.

[0048] If it is determined that power is being supplied (YES in S150), the controller 10 determines whether or not there is a power supply stop command (S152). If the connector 5 attached to the inlet is removed, a power supply stop command is output from the vehicle 4 to the controller 10. If there is a power supply stop command (YES in S152), the vehicle power supply voltage is acquired (S154). If it is determined that the acquired vehicle power supply voltage is greater than the threshold Va (YES in S156), the ON state of the second electromagnetic switch 52 is maintained (S158). On the other hand, if it is determined that the vehicle power supply voltage is less than or equal to the threshold Va (NO in S156), the first electromagnetic switch 51 is switched from the OFF state to the ON state, and the second electromagnetic switch 52 is switched from the ON state to the OFF state (S160).

[0049] Therefore, AC power from the grid power supply 900 is supplied to the load 123 via the leakage circuit breaker 1, the first electromagnetic switch 51, and the overcurrent circuit breaker 113. This ensures that power is continuously supplied to the load 123.

[0050] As described above, according to the power supply system 101 of this embodiment, when the connector 5 is disconnected from the inlet of the vehicle 4 and the controller 10 receives a power supply stop command from the vehicle 4, the power supply source to the load 123 is switched from the vehicle 4 to the grid power supply 900 when the power supply voltage from the vehicle 4 falls below a threshold, so that power supply to the load 123 can be continued. Therefore, it is possible to provide a power supply system that prevents power supply to a power load from being stopped even when power supply from the vehicle is obstructed.

[0051] Furthermore, in this embodiment, by using the first electromagnetic switch 51 and the second electromagnetic switch 52, it is possible to select whether to supply AC power from the grid power supply 900 or AC power from the vehicle 4 to the loads 121-123. More specifically, by turning on the first electromagnetic switch 51 and turning off the second electromagnetic switch 52, AC power from the grid power supply 900 is selected. On the other hand, by turning off the first electromagnetic switch 51 and turning on the second electromagnetic switch 52, AC power from the vehicle 4 is selected. Therefore, according to this embodiment, power from the vehicle 4 or power from the grid power supply 900 can be selectively supplied to the loads 123 with a simple system configuration using two electromagnetic switches.

[0052] The following describes some variations. In the above-described embodiment, the vehicle 4 was described as including a power conversion device that converts the DC power of the vehicle 4's energy storage device to AC power. However, the power supply device 3 may convert the DC power of the vehicle 4's energy storage device to AC power.

[0053] Furthermore, in the above-described embodiment, the first electromagnetic switch 51 was described as being connected between the earth leakage circuit breaker 1 and the overcurrent circuit breaker 113 as an example, but the configuration is not limited to this. The first electromagnetic switch 51 may be connected, for example, between the overcurrent circuit breaker 113 and the load 123.

[0054] Figure 4 shows an example of the configuration of a modified power supply system 101. The configuration of the power supply system 101 shown in Figure 4 differs from the configuration of the power supply system 101 shown in Figure 1 in that the first electromagnetic switch 51 is provided between the overcurrent breaker 113 and the load 123, and the first end of the second electromagnetic switch 52 is connected to a connection node 54 set up between the first electromagnetic switch 51 and the load 123. The other configurations are the same, so detailed explanations will not be repeated except as described below. As shown in Figure 4, the first electromagnetic switch 51 may be provided between the overcurrent breaker 113 and the load 123. The first end of the first electromagnetic switch 51 is connected to the overcurrent breaker 113, and the second end of the second electromagnetic switch 52 is connected to the load 123. Furthermore, the first end of the second electromagnetic switch 52 may be connected to a connection node 54 set up between the second end of the first electromagnetic switch 51 and the load 123. Even in this manner, if a power supply stop command is received while power is being supplied from vehicle 4, the power source to load 123 is switched from vehicle 4 to grid power supply 900 when the vehicle power supply voltage falls below the threshold Va, thus allowing power to be supplied to load 123 to continue.

[0055] Furthermore, in the above-described embodiment, the power supply system 101 may further include, for example, a solar power generation device as a power source.

[0056] Figure 5 shows another example of the configuration of the modified power supply system 101. The power supply system 101 shown in Figure 5 differs from the power supply system 101 shown in Figure 1 in that it further includes a charging device 6, a power conditioner (PCS: Power Conditioning System) 7, a photovoltaic power generation device 8, and a third electromagnetic switch 53. The other configurations are the same as those of the power supply system 101 shown in Figure 1, except as described below, so a detailed explanation will not be repeated.

[0057] As shown in Figure 5, the first end of the third electromagnetic switch 53 is electrically connected to the power conditioner 7. The second end of the third electromagnetic switch 53 is electrically connected to the charging device 6. The third electromagnetic switch 53 is configured to switch the electrical connection and disconnection between the power conditioner 7 and the charging device 6 according to a control command from the controller 10.

[0058] The charging device 6 is configured to be connected to the vehicle 4 via a charging cable (which may be shared with the power supply cable) not shown. The charging device 6 is configured to charge the vehicle 4 with AC power from the power conditioner 7 when the vehicle 4 is connected. The conversion from AC power to DC power may be performed in the charging device 6 or in the vehicle 4.

[0059] The power conditioner 7 receives DC power from the solar power generation device 8 and converts it into AC power. The power conditioner 7 outputs the AC power to the leakage circuit breaker 1 and also to the charging device 6 via the third electromagnetic switch 53.

[0060] Figure 6 is a flowchart showing an example of the control process of an electromagnetic switch according to a modified example. It is assumed that at the start of the series of processes, the first electromagnetic switch 51 is turned on, the second electromagnetic switch 52 is turned off, and the third electromagnetic switch 53 is also turned off.

[0061] In S200, the controller 10 determines whether the power supply device 3 and the charging device 6 are connected to the vehicle 4. If the power supply device 3 and the charging device 6 are connected to the vehicle 4 (YES in S200), the process moves to S201. If the power supply device 3 and the charging device 6 are not connected to the vehicle 4 (NO in S200), this process ends. Note that the process in S200 may be omitted.

[0062] In S201, the controller 10 acquires information regarding the power generated by the solar power generation device 8, as well as information regarding the power consumption (load power) of each load within the house 101A. The controller 10 determines whether the amount of power generated (power generation) within a specified time is greater than the amount of load power (load) within the same specified time. If the amount of power generated is greater than the load (YES in S201), the process moves to S202.

[0063] In S202, the controller 10 determines whether the amount of power generated by the solar power generation device 8 is greater than a predetermined amount. The predetermined amount is set to an amount of power sufficient to charge the vehicle 4. If the amount of power generated is greater than the predetermined amount (YES in S202), the process moves to S203.

[0064] In S203, the controller 10 determines whether the vehicle 4's State of Charge (SOC) is higher than the required value. As mentioned above, the required value can be set to a value corresponding to the amount of electricity required for the vehicle 4 to run the following day. If the SOC is higher than the required value (YES in S203), that is, if the amount of electricity generated by the solar power generation device 8 is sufficient to charge the vehicle 4, but the amount of electricity required for running is already stored in the vehicle 4, the process moves to S204.

[0065] In S204, the controller 10 turns on the first electromagnetic switch 51, turns off the second electromagnetic switch 52, and turns off the third electromagnetic switch 53. The process then ends. At this time, neither power is supplied from the vehicle 4 nor is the vehicle 4 charged. The load 123 is supplied with AC power from the grid power supply 900 or power generated by the solar power generation device 8 (power after AC conversion). If the SOC is below the required value (NO in S203), that is, if the amount of power generated by the solar power generation device 8 is sufficient to charge the vehicle 4 and the amount of power stored in the vehicle 4 is insufficient, the process moves to S205.

[0066] In S205, the controller 10 turns on the first electromagnetic switch 51, turns off the second electromagnetic switch 52, and turns on the third electromagnetic switch 53. The process then ends. At this time, the vehicle 4 is charged with the power generated by the solar power generation device 8. The load 123 is supplied with power from the grid power supply 900 or the solar power generation device 8. If the amount of power generated by the solar power generation device 8 is less than a predetermined amount (NO in S202), that is, if the amount of power generated is greater than the load but is not enough to charge the vehicle 4, the process moves to S206.

[0067] In S206, the controller 10 turns on the first electromagnetic switch 51, turns off the second electromagnetic switch 52, and turns off the third electromagnetic switch 53 (S206). At this time, neither power is supplied from the vehicle 4 nor is the vehicle 4 charged. The load 123 is supplied with AC power from the grid power supply 900 or power generated by the solar power generation device 8. If the amount of power generated by the solar power generation device 8 is less than or equal to the load (NO in S201), that is, if the solar power generation device 8 alone cannot meet the power demand of the house 101A, the process moves to S207.

[0068] In S207, the controller 10 determines whether the vehicle 4's SOC is higher than the required value. The required value may be the same as the required value in S203, or it may be a different value. If the SOC is higher than the required value (YES in S207), that is, if there is sufficient power stored in the vehicle 4, the process moves to S208. If the SOC is higher than or equal to the required value (NO in S207), the process moves to S211.

[0069] In S208, the controller 10 obtains information about the electricity charges from, for example, the energy management server when the vehicle 4 was last charged. The process then moves to S209.

[0070] In S209, the controller 10 calculates the difference between the current electricity bill and the electricity bill from the previous charge, for which information was obtained in S208, and determines whether the difference is greater than or equal to the threshold α. If the difference is greater than the threshold α (YES in S209), the process moves to S210. If the difference is less than or equal to the threshold α (NO in S209), the process moves to S213. Note that in S209, the same process as in S106 in Figure 3 is performed, so a detailed explanation is omitted.

[0071] In S210, the controller 10 turns off the first electromagnetic switch 51, turns on the second electromagnetic switch 52, and turns off the third electromagnetic switch 53. In other words, power is supplied from the vehicle 4 to the load 123 instead of from the grid power supply 900. If the SOC is below the required value (NO in S207), that is, if there is not enough power stored in the vehicle 4 to supply power to the outside, the process moves to S211.

[0072] In S211, the controller 10 determines whether or not there is a charging command for vehicle 4 (S211). If there is a charging command (YES in S211), the process moves to S212.

[0073] In S212, the controller 10 turns on the first electromagnetic switch 51, turns off the second electromagnetic switch 52, and turns on the third electromagnetic switch 53. At this time, the vehicle 4 is charged with the power generated by the solar power generation device 8. The load 123 is supplied with AC power from the grid power supply 900 or the power generated by the solar power generation device 8. If there is no charge command (NO in S211), the process moves to S213.

[0074] In S213, the controller 10 turns on the first electromagnetic switch 51, turns off the second electromagnetic switch 52, and turns off the third electromagnetic switch 53 (S213). At this time, no power is supplied from the vehicle 4, nor is the vehicle 4 charged.

[0075] In this modified example, similar to the embodiment described above, the power supply system 101 includes a third electromagnetic switch 53 in addition to the first electromagnetic switch 51 and the second electromagnetic switch 52. This allows for a simple system configuration, requiring only the addition of a third electromagnetic switch, to charge the vehicle 4 using power generated by the solar power generation device 8, in addition to power supplied from the vehicle 4.

[0076] Furthermore, in the above-described embodiment, a configuration in which the first electromagnetic switch 51 is provided between the circuit PL1 and the overcurrent breaker 113 was explained as an example. However, it may also be provided on the circuit PL1 at a position closer to the leakage breaker 1 than the branching point to the overcurrent breaker 111.

[0077] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0078] 1 Earth leakage circuit breaker, 3 Power supply device, 4 Vehicle, 5 Connector, 6 Charging device, 7 Power conditioner, 8 Solar power generation device, 10 Controller, 11 Processor, 12 Memory, 13 Voltage measurement unit, 51 First electromagnetic switch, 52 Second electromagnetic switch, 53 Third electromagnetic switch, 101 Power supply system, 101A House, 111, 112, 113, 211, 212 Overcurrent breaker, 121, 122, 123, 221, 222 Load, 900 System power supply, PL1, PL2 Circuit.

Claims

1. A power supply system that supplies AC power from the grid to the power load of a house, Vehicles equipped with energy storage devices, A current circuit breaker that receives AC power from the aforementioned power grid to the house and interrupts the current at least in the event of an overcurrent, A load circuit breaker configured to electrically interrupt the connection between the current circuit breaker and the power load, A first switch configured to switch between electrical connection and disconnection between the current circuit breaker and the power load, A second switch is provided on a power line branched from the power line between the first switch and the power load, and is configured to switch between electrical connection and disconnection between the power load and the vehicle. The system includes a control device that controls the operation of the first switch and the second switch, The control device is a power supply system that, when a power supply stop command is received while power is being supplied from the vehicle, switches the power source to the power load from the vehicle to the grid power supply when the power supply voltage from the vehicle falls below a threshold.

2. The power supply system according to claim 1, wherein the vehicle transmits the power supply stop command to the control device in at least one of the following cases: when the connection between the vehicle and the second switch is terminated, or when an operation to stop the power supply is received.

3. The control device is When supplying power from the aforementioned power grid to the power load, the first switch is closed and the second switch is opened. The power supply system according to claim 1, wherein when supplying power from the vehicle to the power load, the first switch is opened and the second switch is closed.

4. The aforementioned house includes a power conditioner that receives the electricity generated by the solar power generation system. The power conditioner is configured to supply AC power to the vehicle when the vehicle is connected. The power supply system according to claim 1, further comprising a third switch configured to switch between electrical connection and disconnection between the power conditioner and the vehicle.

5. The control device is When power is supplied from the vehicle, the first switch is opened, the second switch is closed, and the third switch is opened. When charging the vehicle, the first switch is closed, the second switch is opened, and the third switch is closed. The power supply system according to claim 4, wherein when neither power is supplied from the vehicle nor the vehicle is being charged, the first switch is closed, the second switch is opened, and the third switch is opened.

6. The power supply system according to any one of claims 1 to 5, wherein the control device opens the first switch and closes the second switch when the vehicle and the second switch are connected, and the current electricity cost is higher than the electricity cost of supplying the power currently charged to the vehicle.

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