CHARGE AND DISCHARGE SYSTEM, VEHICLE, AND CONTROL METHOD FOR CHARGE AND DISCHARGE SYSTEM

A charge and discharge system capable of being charged and discharged from and to an external device includes a charge and discharge circuit, a switching system and a controller. The charge and discharge circuit converts electric power from an inlet to direct-current power compatible with an electrical storage device and converts direct-current power of the electrical storage device to electric power that is discharged from an outlet. The switching system connects the charge and discharge circuit to the inlet or to the outlet. The controller determines that the switching system has a failure on condition that an alternating-current voltage has been detected at the inlet and an alternating-current voltage has been detected at the outlet, and disable charging and discharging.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2022-017880 filed on Feb. 8, 2022, incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The disclosure relates to a charge and discharge system, a vehicle, and a control method for a charge and discharge system and, particularly, to a charge and discharge system capable of performing charging and discharging from and to an external device, a vehicle that includes the charge and discharge system, and a control method for the charge and discharge system.

2. Description of Related Art

There has been a power supply system capable of charging a main battery and an auxiliary battery from a system power supply and capable of outputting electric power for electric home appliances by using the main battery as a power supply without an exclusive DC/AC converter (see, for example, Japanese Unexamined Patent Application Publication No. 2008-312395 (JP 2008-312395 A)). The power supply system described in JP 2008-312395 A includes a plug to which electric power is input during charging and a receptacle from which electric power is output during feeding. Connection of two power lines for connecting the power supply system with the plug or the receptacle is switched by a C-contact relay. A C-contact relay is a relay in which, when a current is flowing through a coil, a common contact and a normally open contact are connected and the common contact and a normally closed contact are cut off, while, when no current is flowing through the coil, the common contact and the normally closed contact are connected and the common contact and the normally open contact are disconnected.

SUMMARY

However, in the power supply system described in JP 2008-312395 A, if there occurs an all-short-circuit failure that all the three terminals, that is, the common contact, normally open contact, and normally closed contact of the C-contact relay, an electric power not supported by a device connected to the receptacle (outlet) can be applied to the device from the plug (inlet) via the receptacle (outlet).

The disclosure provides a charge and discharge system, a vehicle, and a control method for a charge and discharge system, which are capable of reducing the possibility that an electric power not supported by a device connected to an outlet is applied to the device.

An aspect of the disclosure provides a charge and discharge system. The charge and discharge system is capable of performing charging and discharging from and to an external device. The charge and discharge system includes a charge and discharge circuit configured to convert electric power from an inlet to direct-current power compatible with an electrical storage device configured to store electric power and convert direct-current power of the electrical storage device to electric power that is discharged from an outlet; a switching system configured to switch between a state where the charge and discharge circuit and the inlet are electrically connected and a state where the charge and discharge circuit and the outlet are electrically connected; a controller configured to control the switching system; a first voltage sensor configured to detect an alternating-current voltage at the inlet; and a second voltage sensor configured to detect an alternating-current voltage at the outlet. The inlet is connected to a connector that supplies electric power from an external device. The outlet is connected to a plug that discharges electric power to an external device. The controller is configured to determine that the switching system has a failure on condition that an alternating-current voltage has been detected by the first voltage sensor at the inlet and an alternating-current voltage has been detected by the second voltage sensor at the outlet, and disable charging and discharging.

When an alternating-current voltage has been detected at the inlet and an alternating-current voltage has been detected at the outlet, it is presumable that the inlet and the outlet are electrically continuous. With such a configuration, when an alternating-current voltage has been detected at the inlet and an alternating-current voltage has been detected at the outlet, it is determined that the switching system has a failure, and charging and discharging are disabled. As a result, it is possible to provide a charge and discharge system capable of reducing the possibility that an electric power not supported by a device connected to the outlet is applied to the device.

The controller may be configured to disable charging and discharging by controlling the charge and discharge circuit such that conversion of electric power is not performed.

With such a configuration, application of electric power from the electrical storage device via the charge and discharge circuit to the device connected to the outlet is prevented.

The controller may be configured to disable charging and discharging by disabling supply of electric power from an external apparatus that supplies electric power to the inlet.

With such a configuration, application of electric power from the external apparatus, which supplies electric power, via the inlet to the device connected to the outlet is prevented.

The second voltage sensor may be configured to be capable of detecting not only an alternating-current voltage but also a direct-current voltage at the outlet, and the controller may be configured to determine that the switching system has no failure on condition that an alternating-current voltage has been detected by the first voltage sensor at the inlet and a direct-current voltage has been detected by the second voltage sensor at the outlet, and enable charging and discharging.

Although an alternating-current voltage input from the inlet is not applied to the outlet, a voltage can be detected at the outlet side due to electric charge remaining in a capacitor of the device connected to the outlet. With such a configuration, when the detected voltage at the outlet is a direct-current voltage, it may be determined that an alternating-current voltage at the inlet is not applied to the outlet, so it is determined that the switching system has no failure. As a result, it is possible to determine that the switching system has no failure and enable charging and discharging when an alternating-current voltage has been detected at the inlet and a direct-current voltage has been detected at the outlet.

The first voltage sensor may be configured to be capable of detecting not only an alternating-current voltage but also a direct-current voltage at the inlet, and the controller may be configured to determine that the switching system has a failure on condition that a direct-current voltage has been detected by the first voltage sensor at the inlet and a direct-current voltage has been detected by the second voltage sensor at the outlet, and disable charging and discharging.

A voltage can be detected at the outlet side due to electric charge remaining in a capacitor of the device connected to the outlet. With such a configuration, when the detected voltage at the outlet is direct current and the detected voltage at the inlet is direct current, it may be determined that a direct-current voltage at the outlet is applied to the inlet, so it may be determined that the switching system has a failure. As a result, it is possible to determine that the switching system has a failure when a direct-current voltage has been detected at the inlet and a direct-current voltage has been detected at the outlet, and disable charging and discharging.

Another aspect of the disclosure provides a vehicle. The vehicle may include the above-described charge and discharge system, the inlet, the outlet, and the electrical storage device. With such a configuration, it is possible to provide a vehicle capable of reducing the possibility that an electric power not supported by a device connected to the outlet is applied to the device.

Further another aspect of the disclosure provides a control method for a charge and discharge system capable of performing charging and discharging from and to an external apparatus. The charge and discharge system includes a charge and discharge circuit configured to convert electric power from an inlet to direct-current power compatible with an electrical storage device configured to store electric power and convert direct-current power of the electrical storage device to electric power that is discharged from an outlet; a switching system configured to switch between a state where the charge and discharge circuit and the inlet are electrically connected and a state where the charge and discharge circuit and the outlet are electrically connected; a controller configured to control the switching system; a first voltage sensor configured to detect a voltage of electric power at the inlet; and a second voltage sensor configured to detect a voltage of electric power at the outlet. The inlet is connected to a connector that supplies electric power from an external device. The outlet is connected to a plug that discharges electric power to an external device. The control method includes, by the controller, determining that the switching system has a failure on condition that an alternating-current voltage has been detected by the first voltage sensor at the inlet and an alternating-current voltage has been detected by the second voltage sensor at the outlet; and disabling charging and discharging when it is determined that the switching system has a failure.

With such a configuration, it is possible to provide a control method for a charge and discharge system, capable of reducing the possibility that an electric power not supported by a device connected to the outlet is applied to the device.

According to the aspects of the disclosure, it is possible to provide a charge and discharge system, a vehicle, and a control method for a charge and discharge system, which are capable of reducing the possibility that an electric power not supported by a device connected to an outlet is applied to the device.

DETAILED DESCRIPTION OF EMBODIMENTS

First Embodiment

Hereinafter, an embodiment of the disclosure will be described in detail with reference to the accompanying drawings. Like reference signs denote the same or corresponding portions in the drawings, and the description thereof will not be repeated.

Configuration of Vehicle and Power Supply Facility

FIG.1is a diagram showing an example of the overall configuration of a charging system that includes a vehicle1provided with a bidirectional charger200and a power supply facility300according to the embodiment. As shown inFIG.1, the charging system includes the vehicle1and the power supply facility300. The power supply facility300is a facility for supplying alternating-current power to the vehicle1. An example in which the vehicle1according to the present embodiment is a battery electric vehicle (hereinafter, also referred to as BEV) will be described.

The vehicle1includes an electrical storage device10, a current sensor15, a system main relay (hereinafter, also referred to as SMR)20, a power control unit (hereinafter, also referred to as PCU)30, a power output unit40, a drive wheel50, an inlet70, a charging relay60, the bidirectional charger200, an outlet80, an electronic control unit (ECU)100, and a human machine interface (HMI)130.

The electrical storage device10is a rechargeable direct-current power supply and is, for example, a nickel-metal hydride secondary battery, a lithium ion secondary battery, or the like. The electrical storage device10stores not only electric power supplied from an alternating-current power supply310of the power supply facility300but also electric power generated by the power output unit40. A large-capacitance capacitor may also be employed as the electrical storage device10.

The current sensor15detects a charging current D3input to or output from the electrical storage device10and outputs a detection result to the ECU100.

The SMR20is provided between the electrical storage device10and power lines PL1, NL1. The SMR20is a relay used to electrically connect the electrical storage device10to the power lines PL1, NL1or electrically disconnect the electrical storage device from the power lines PL1, NL1.

The PCU30is a collection of power conversion devices for driving the power output unit40by using electric power supplied from the electrical storage device10. The PCU30includes, for example, an inverter for driving a motor included in the power output unit40, a converter that steps up electric power output from the electrical storage device10, and the like.

The power output unit40is a collection of devices for driving the drive wheel50. The power output unit40includes, for example, a motor generator or the like that drives the drive wheel50. The power output unit40generates electric power during, for example, braking of the vehicle1with the motor generator that drives the drive wheel50and outputs the generated electric power to the PCU30.

The inlet70is electrically connected to input lines ACL1, ACL2of the bidirectional charger200. The inlet70is configured to be able to connect with a connector340of the power supply facility300. Signal lines L1, L2are provided between the inlet70and the ECU100. The signal line L1is a signal line for transmitting a pilot signal CPLT for exchanging predetermined information between the vehicle1and the power supply facility300. The signal line L2is a signal line for transmitting a connector connection signal PISW that indicates the connection status between the inlet70and the connector340.

In the present embodiment, the outlet80is a receptacle for alternating-current 100 V and is configured to be able to connect with a plug810of a device800that operates on 100 V alternating-current power. As shown inFIG.1, in the device800, a capacitor820can be connected to power lines connected to the plug810. The other end of the capacitor820is connected to a ground830. The outlet80is electrically connected to the bidirectional charger200.

The charging relay60is a relay used to connect the bidirectional charger200to the power lines PL1, NL1or electrically disconnect the bidirectional charger200from the power lines PL1, NL1. The charging relay60switches the open-closed state based on a control signal from the ECU100.

The bidirectional charger200is electrically connected to the electrical storage device10via the charging relay60. The bidirectional charger200, in accordance with a command from the ECU100, converts alternating-current power input to the inlet70to direct-current power having a charging voltage of the electrical storage device10or converts the direct-current power of the electrical storage device10to alternating-current power output from the outlet80. Direct-current power converted by the bidirectional charger200from alternating-current power coming from the inlet70is supplied to the electrical storage device10via the charging relay60to charge the electrical storage device10. Alternating-current power converted by the bidirectional charger200from direct-current power coming from the electrical storage device10is supplied via the outlet80to the device800connected to the outlet80.

The ECU100is configured to include a central processing unit (CPU)110, a memory120, and an input-output buffer (not shown) for inputting or outputting various signals. The memory120includes a random access memory (RAM), and a read only memory (ROM). The CPU110expands a program stored in the ROM onto the RAM and runs the program. The program stored in the ROM describes a process that is executed by the CPU110. The ECU100uses the CPU110to execute a predetermined computation process based on various signals input from the input-output buffer and information stored in the memory120in accordance with the program, and controls the devices (the SMR20, the PCU30, the charging relay60, the bidirectional charger200, and the like) based on the computation result such that the vehicle1becomes a desired state. These controls are not limited to software processing and may be processed by constructing exclusive hardware (electronic circuit).

The HMI130is controlled by the ECU100to display predetermined information or inform a user by voice in response to running of a program.

The power supply facility300includes the alternating-current power supply310outside the vehicle, electric vehicle supply equipment (EVSE)320, and a charging cable330. The connector340configured to be able to connect with the inlet70of the vehicle1is provided at the distal end of the charging cable330.

The alternating-current power supply310is made up of, for example, a commercial system power supply; however, the alternating-current power supply310is not limited thereto. Various power supplies are applicable.

The EVSE320controls supply and cut-off of alternating-current power to the vehicle1from the alternating-current power supply310via the charging cable330. The EVSE320is provided in, for example, a charging station for supplying electric power to the vehicle1. The EVSE320is to meet, for example, required specifications of “SAEJ1772 (SAE Electric Vehicle Conductive Charge Coupler) standard”. The function of the EVSE320is not limited to being provided in a charging station. Alternatively, for example, a charging circuit interrupt device (CCID) box having the function of the EVSE320may be provided in a charging cable. In this case, for example, a receptacle plug provided at one end (opposite side to the connector340) of the charging cable is connected to the alternating-current power supply310.

The EVSE320includes a CCID321and a CPLT control circuit322. The CCID321is a relay provided in a power supply path from the alternating-current power supply310to the vehicle1and is controlled by the CPLT control circuit322. In this embodiment, the EVSE320of the power supply facility300is assumed to be able to supply 200 V alternating-current power to the vehicle1.

The CPLT control circuit322generates a pilot signal CPLT to be communicated with the ECU100of the vehicle1and outputs the pilot signal CPLT to the ECU100through an exclusive signal line included in the charging cable330. The potential of the pilot signal CPLT is controlled by the ECU100. The CPLT control circuit322controls the CCID321based on the potential of the pilot signal CPLT. In other words, by operating the potential of the pilot signal CPLT in the ECU100, it is possible to remotely operate the CCID321from the ECU100.

FIG.2is a diagram showing an example of the configuration of the bidirectional charger200according to the embodiment. As shown inFIG.2, the bidirectional charger200includes the charge and discharge circuit210, switching relays220,230, and voltage sensors240,250,260for both alternating current and direct current.

The charge and discharge circuit210, in accordance with a control signal from the ECU100, converts alternating-current power from the inlet70to direct-current power compatible with the electrical storage device10or converts the direct-current power of the electrical storage device10to electric power output that is discharged from the outlet80.

Each of the switching relays220,230is a C-contact relay in this embodiment. The switching relays220,230make up a switching system that switches, in accordance with a control signal from the ECU100, between a state where the charge and discharge circuit210and the inlet70are electrically connected and a state where the charge and discharge circuit210and the outlet80are electrically connected. Specifically, the common contacts of the switching relays220,230are respectively connected to two terminals of the charge and discharge circuit210, the normally closed contacts of the switching relays220,230are respectively connected to two terminals of the inlet70, and the normally open contacts of the switching relays220,230are respectively connected to two terminals of the outlet80.

The voltage sensor240detects a direct-current voltage and an alternating-current voltage between the power lines provided between the charge and discharge circuit210and both the switching relays220,230, and outputs signals indicating the detected type (direct current or alternating current) and voltage value of electric power to the ECU100.

The voltage sensor250detects a direct-current voltage and an alternating-current voltage between the power lines provided between the inlet70and both the switching relays220,230, and outputs signals indicating the detected type (direct current or alternating current) and voltage value of electric power to the ECU100.

The voltage sensor260detects a direct-current voltage and an alternating-current voltage between the power lines provided between the outlet80and both the switching relays220,230, and outputs signals indicating the detected type (direct current or alternating current) and voltage value of electric power to the ECU100.

In the bidirectional charger200, if there occurs an all-short-circuit failure that all the three terminals, that is, the common contact, normally open contact, and normally closed contact of each of the switching relays220,230that are the C-contact relays, there is a possibility that electric power not supported by the device800can be applied from the inlet70via the outlet80to the device800connected to the outlet80.

The ECU100determines that the switching relays220,230have a failure on condition that an alternating-current voltage has been detected by the voltage sensor250at the inlet70and an alternating-current voltage has been detected by the voltage sensor260at the outlet80, and disables charging and discharging.

When an alternating-current voltage has been detected at the inlet70and an alternating-current voltage has been detected at the outlet80, it is presumable that the inlet70and the outlet80are electrically continuous. With the above-described configuration, when an alternating-current voltage has been detected at the inlet70and an alternating-current voltage has been detected at the outlet80, it is determined that the switching relays220,230have a failure, and charging and discharging are disabled. As a result, it is possible to reduce the possibility that an electric power not supported by the device800connected to the outlet80is applied to the device800.

FIG.3is a flowchart showing the flow of a charging start pre-process according to a first embodiment. As shown inFIG.3, the charging start pre-process is called and executed at predetermined intervals from a higher-level process by the CPU110of the ECU100.

The CPU110uses a connector connection signal PISW to determine whether the connector340is connected to the inlet70(step S111). When the CPU110determines that the connector340is not connected (NO in step S111), the CPU110returns the process of the charging start pre-process to the higher-level calling process.

On the other hand, when the CPU110determines that the connector340is connected (YES in step S111), the CPU110switches the connection destination of the switching relays220,230that are C-contact relays to the bidirectional charger200from the outlet80side to the inlet70side (step S112).

Subsequently, the CPU110switches the charging relay60into a connected state (step S113) and switches the CCID321into a connected state (step S114). After that, the CPU110controls the bidirectional charger200such that the bidirectional charger200performs charging operation for a short time until failure determination of the switching relays220,230, which will be described below, ends (step S115).

The CPU110determines whether a voltage has been detected at the inlet70by using a signal from the voltage sensor250(step S121). When the CPU110determines that no voltage has been detected at the inlet70(NO in step S121), that is, when no voltage is applied at the inlet70although the connector340is connected and electric power is being supplied from the power supply facility300via the connector340to the inlet70of the vehicle1, the CPU110determines that there is another failure (step S131). Another failure is a failure other than a failure of the switching relays220,230, such as a failure to switch from the outlet80side of the switching relays220,230to the inlet70side and a break of a charging system from the power supply facility300to the vehicle1.

When the CPU110determines that a voltage has been detected at the inlet70(YES in step S121), the CPU110determines whether a voltage has been detected at the outlet80by using a signal from the voltage sensor260(step S122).

When the CPU110determines that a voltage has been detected at the outlet80(YES in step S122), the CPU110determines whether the outlet80-side voltage is a direct-current voltage by using a signal from the voltage sensor260(step S123).

When the CPU110determines that the outlet80-side voltage is a direct-current voltage (YES in step S123), the CPU110determines whether the inlet70-side voltage is a direct-current voltage by using a signal from the voltage sensor250(step S124).

When the CPU110determines that no voltage has been detected at the outlet80(NO in step S122) or when the CPU110determines that the inlet70-side voltage is not a direct-current voltage (NO in step S124), the CPU110determines that the switching relays220,230do not have an all-short-circuit failure (step S125) and controls the bidirectional charger200such that the bidirectional charger200starts charging control (step S126). After step S126, the CPU110returns the process of the charging start pre-process to the calling process.

When the CPU110determines that the outlet80-side voltage is not a direct-current voltage (NO in step S123) or when the CPU110determines that the inlet70-side voltage is a direct-current voltage (YES in step S124), the CPU110determines that the switching relays220,230have an all-short-circuit failure (step S132).

After step S131or step S132, the CPU110switches the CCID321into a disconnected state (step S133), switches the charging relay60into a disconnected state, and stops the charge and discharge circuit210(step S134). Then, the CPU110controls the HMI130such that the HMI130informs the details of the failure (step S135). After step S135, the CPU110returns the process of the charging start pre-process to the calling process.

Second Embodiment

In the first embodiment, whether to determine that the switching relays220,230have a failure is branched off as shown in step S121, step S122, step S123, and step S124inFIG.3, in accordance with a voltage at the inlet70and a voltage at the outlet80. In a second embodiment, as will be described below with reference toFIG.4, whether the switching relays220,230have a failure is branched off.

FIG.4is a flowchart showing the flow of a charging start pre-process according to the second embodiment. As shown inFIG.4, the charging start pre-process is called and executed at predetermined intervals from a higher-level process by the CPU110of the ECU100. Processes other than step S141, step S142, and step S143inFIG.4are the same as those ofFIG.3, so the description will not be repeated.

After step S115, the CPU110determines whether a voltage has been detected at the inlet70by using a signal from the voltage sensor250(step S141). When the CPU110determines that no voltage has been detected at the inlet70side (NO in step S141), the CPU110proceeds with the process to the processes of step S131and the subsequent processes, described with reference toFIG.3.

When the CPU110determines that a voltage has been detected at the inlet70(YES in step S141), the CPU110determines whether the inlet70side is alternating current and the outlet80side is alternating current (step S142).

When the CPU110determines that at least any one of the inlet70side and the outlet80side is not alternating current (NO in step S142), the CPU110determines whether the inlet70side is direct current and the outlet80side is direct current (step S143).

When the CPU110determines that the inlet70side is alternating current and the outlet80side is alternating current (YES in step S142) or when the inlet70side is direct current and the outlet80side is direct current (YES in step S143), the CPU110proceeds with the process to the processes of step S132and the subsequent processes, described with reference toFIG.3.

When the CPU110determines that at least any one of the inlet70side and the outlet80side is not direct current (NO in step S143), that is, when the inlet70side is alternating current and the outlet80side is direct current or when the inlet70side is alternating current and no voltage is applied at the outlet80side, the CPU110proceeds with the process to the processes of step S125and the subsequent processes, described with reference toFIG.3.

Third Embodiment

In the above-described first embodiment and second embodiment, as described with reference toFIG.2, the switching system that switches between a state where the charge and discharge circuit210and the inlet70are electrically connected and a state where the charge and discharge circuit210and the outlet80are electrically connected in accordance with a control signal from the ECU100is made up of the switching relays220,230that are two C-contact relays. In a third embodiment, the switching system is made up of two A-contact relays and two B-contact relays.

FIG.5is a diagram showing an example of the configuration of a bidirectional charger200A according to the third embodiment. Components other than switching relays271,272,273,274of the bidirectional charger200A are similar to those of the bidirectional charger200described with reference toFIG.2, so the description will not be repeated.

Each of the switching relays271,273is an A-contact relay in this embodiment. Each of the switching relays272,274is a B-contact relay in this embodiment. An A-contact relay is a relay in which, when a current is flowing through a coil, a common contact and a normally open contact are connected, and, when no current is flowing through the coil, the common contact and the normally open contact are disconnected. A B-contact relay is a relay in which, when a current is flowing through a coil, a common contact and a normally closed contact are connected, and, when no current is flowing through the coil, the common contact and the normally closed contact are disconnected.

The switching relays271,272,273,274make up a switching system that switches, in accordance with a control signal from the ECU100, between a state where the charge and discharge circuit210and the inlet70are electrically connected and a state where the charge and discharge circuit210and the outlet80are electrically connected. Specifically, the common contact of the switching relays271,272is connected to one of the terminals of the charge and discharge circuit210, and the common contact of the switching relays273,274is connected to the other one of the terminals of the charge and discharge circuit210. The normally open terminals of the switching relays271,273that are A-contact relays are respectively connected to two terminals of the inlet70. The normally closed terminals of the switching relays272,274that are B-contact relays are respectively connected to two terminals of the outlet80.

In the third embodiment, in the process described with reference to step S112ofFIG.3andFIG.4, the CPU110switches the common terminal connected to the charge and discharge circuit210and the normally open terminal connected to the inlet70into a connected state by passing current through the coils of the switching relays271,273that are A-contact relays, and switches the common terminal connected to the charge and discharge circuit210and the normally closed terminal connected to the outlet80into a disconnected state by passing current through the coils of the switching relays272,274that are B-contact relays. Thus, the destination to which the bidirectional charger200is connected is switched from the outlet80side to the inlet70side.

Other Modifications

In the above-described first embodiment, as shown inFIG.1, the vehicle1is assumed as a BEV. However, the vehicle1is not limited thereto. The vehicle1just needs to be a vehicle capable of performing charging and discharging from and to an external device. The vehicle1may be a plug-in hybrid electric vehicle (hereinafter, also referred to as PHEV) or a fuel cell electric vehicle (FCEV) that has an external charging function. When the vehicle1is a PHEV, the power output unit40may include, for example, an engine in addition to a motor.

In the above-described embodiments, as shown inFIG.1andFIG.2, alternating-current power is input from the inlet70for charging. Then, the charge and discharge circuit210of the bidirectional charger200converts the alternating-current power input from the inlet70to direct-current power of a voltage compatible with the electrical storage device10, and outputs the direct-current power to the electrical storage device10.

However, the configuration is not limited thereto. Direct-current power may be input from the inlet70for charging. Then, the charge and discharge circuit210of the bidirectional charger200may convert the direct-current power input from the inlet70to direct-current power of a voltage compatible with the electrical storage device10, and outputs the direct-current power to the electrical storage device10.

In the above-described embodiments, as shown inFIG.1andFIG.2, the outlet80is an alternating-current 100 V receptacle. However, the configuration is not limited thereto. The outlet80may output alternating-current power of another voltage or output direct-current power of a predetermined voltage. The outlet80may be, for example, a direct-current 12 V cigar lighter socket or a direct-current 5 V universal serial bus (USB) socket.

In the above-described first embodiment and second embodiment, as described with reference toFIG.2, the switching system that switches, in accordance with a control signal from the ECU100, between a state where the charge and discharge circuit210and the inlet70are electrically connected and a state where the charge and discharge circuit210and the outlet80are electrically connected is made up of the switching relays220,230that are two C-contact relays. In the third embodiment, as described with reference toFIG.5, the switching system is made up of the switching relays271,273that are two A-contact relays and the switching relays272,274that are two B-contact relays. However, the configuration is not limited thereto. The switching system may be made up of the switching relays271,273that are two B-contact relays and the switching relays272,274that are two A-contact relays.

The above-described embodiments may be regarded as the disclosure of the vehicle1, the charge and discharge system such as the bidirectional chargers200,200A, or the controller for a charge and discharge system such as the ECU100or may be regarded as the disclosure of a control method that is executed by the controller or a control program that is run by the controller in the vehicle1or the charge and discharge system.

Summary

As shown inFIG.1,FIG.2, andFIG.5, each of the bidirectional chargers200,200A is capable of performing charging and discharging from and to an external device. Each of the bidirectional chargers200,200A includes the charge and discharge circuit210, the switching system (the switching relays220,230or the switching relays271,272,273,274), the ECU100, the voltage sensor250, and the voltage sensor260. The charge and discharge circuit210converts electric power from the inlet70for connection with the connector340for supplying electric power from an external device to direct-current power compatible with the electrical storage device configured to store electric power, and converts direct-current power of the electrical storage device10from the outlet80for connection with the plug810for discharging electric power to an external device. The switching system switches between a state where the charge and discharge circuit210and the inlet70are electrically connected and a state where the charge and discharge circuit210and the outlet80are electrically connected. The ECU100controls the switching system. The voltage sensor250detects an alternating-current voltage at the inlet70. The voltage sensor260detects an alternating-current voltage at the outlet80. As shown inFIG.3andFIG.4, the ECU100determines that the switching system has a failure on condition that an alternating-current voltage has been detected by the voltage sensor250at the inlet70and an alternating-current voltage has been detected by the voltage sensor260at the outlet80(step S132) and disables charging and discharging (step S133, step S134).

When an alternating-current voltage has been detected at the inlet70and an alternating-current voltage has been detected at the outlet80, it is presumable that the inlet70and the outlet80are electrically continuous. With the above-described configuration, when an alternating-current voltage has been detected at the inlet70and an alternating-current voltage has been detected at the outlet80, it is determined that the switching system has a failure, and charging and discharging are disabled. As a result, it is possible to reduce the possibility that an electric power not supported by the device connected to the outlet80is applied to the device.

As shown inFIG.3andFIG.4, the ECU100may disable charging and discharging by controlling the charge and discharge circuit210such that conversion of electric power is not performed (step S134).

With the above-described configuration, application of electric power from the electrical storage device10via the charge and discharge circuit210to the device800connected to the outlet80is prevented.

As shown inFIG.3andFIG.4, the ECU100may disable charging and discharging by disabling supply of electric power from the power supply facility300, which supplies electric power to the inlet70(step S133).

With the above-configuration, application of electric power from the power supply facility300, which supplies electric power, via the inlet70to the device800connected to the outlet80is prevented.

As shown inFIG.2andFIG.5, the voltage sensor260is capable of detecting not only an alternating-current voltage but also a direct-current voltage at the outlet80. As shown inFIG.3andFIG.4, the ECU100may determine that the switching system has no failure on condition that an alternating-current voltage has been detected by the voltage sensor250at the inlet70and a direct-current voltage has been detected by the voltage sensor260at the outlet80(step S125) and enable charging and discharging (step S126).

Although an alternating-current voltage input from the inlet70is not applied to the outlet80, a voltage can be detected at the outlet80side due to electric charge remaining in the capacitor820of the device connected to the outlet80. With the above configuration, when the detected voltage at the outlet80is a direct-current voltage, it may be determined that an alternating-current voltage at the inlet70is not applied to the outlet80, so it is determined that the switching system has no failure. As a result, it is possible to determine that the switching system has no failure when an alternating-current voltage has been detected at the inlet70and a direct-current voltage has been detected at the outlet80, and enable charging and discharging.

As shown inFIG.2andFIG.5, the voltage sensor250is capable of detecting not only an alternating-current voltage but also a direct-current voltage at the inlet70. As shown inFIG.3andFIG.4, the ECU100determines that the switching system has a failure on condition that a direct-current voltage has been detected by the voltage sensor250at the inlet70and a direct-current voltage has been detected by the voltage sensor260at the outlet80(step S132) and disables charging and discharging (step S133, step S134).

A voltage can be detected at the outlet80side due to electric charge remaining in the capacitor820of the device800connected to the outlet80. With the above configuration, when the detected voltage at the outlet80is direct current and the detected voltage at the inlet70is direct current, it may be determined that a direct-current voltage at the outlet80is applied to the inlet70, so it may be determined that the switching system has a failure. As a result, it is possible to determine that the switching system has a failure when a direct-current voltage has been detected at the inlet70and a direct-current voltage has been detected at the outlet80and disable charging and discharging.

The embodiments described above are illustrative and not restrictive in all respects. The scope of the disclosure is not defined by the description of the above-described embodiments, and is defined by the appended claims. The scope of the disclosure is intended to encompass all modifications within the scope of the appended claims and equivalents thereof