Ground fault protection for charging system and electrically powered vehicle

An ECU performs a program including: during charging, when abnormality information has been received, bringing each of an SMR and a CHR into an OFF state; when a charging connector is disconnected and when a vehicle is in a Ready-On state, starting a ground fault detection process; when it is determined that a ground fault has occurred on the vehicle side, performing a display process (1); and in the state where it is not determined that a ground fault has occurred on the vehicle side, when a prescribed detection time period has elapsed, performing a display process (2).

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional application claims priority to Japanese Patent Application No. 2016-167615 filed on Aug. 30, 2016, with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.

BACKGROUND

Field

The present disclosure relates to control of a charging system and an electrically powered vehicle, which is executed when a ground fault occurs during charging of a power storage device mounted in the electrically powered vehicle using a charging facility external to the electrically powered vehicle.

Description of the Background Art

There is a known technique for charging a power storage device mounted in an electrically powered vehicle using a charging facility external to the vehicle. As an example of such a technique, Japanese Patent Laying-Open No. 2010-239845 discloses a technique for cutting off power supply to a battery mounted in a vehicle by using a leakage interrupter when a ground fault is detected by a ground fault detector provided in a charging facility external to the vehicle during charging using the charging facility.

SUMMARY

When a ground fault is detected by the ground fault detector provided in the charging facility, however, it cannot be distinguished whether a ground fault occurs in the charging facility or the electrically powered vehicle. This is because an electrical connection is established between the charging facility and the power storage device mounted in the electrically powered vehicle.

The present disclosure has been made to solve the above-described problems. An object of the present disclosure is to provide a charging system and an electrically powered vehicle, by which it is distinguished whether the vehicle can be used or not, when a ground fault occurs during charging of a power storage device mounted in the vehicle using a charging facility external to the vehicle.

A charging system according to an aspect of the present disclosure includes: an electrically powered vehicle provided with a power storage device configured to supply electric power to a driving motor; and a charging facility provided external to the electrically powered vehicle and configured to charge the power storage device. The charging facility includes a power supply, a charging connector that is connectable to the electrically powered vehicle, a charger configured to charge the power storage device using electric power of the power supply when the charging connector is connected to the electrically powered vehicle, and a first detector for detecting, during charging of the power storage device, a ground fault in a charging path extending from the power supply to the power storage device. The charging facility is configured to, when the ground fault is detected by the first detector during charging, stop charging of the power storage device and transmit abnormality information indicating occurrence of the ground fault to the electrically powered vehicle. The charging path includes (i) a first path for connecting the power supply and the charging connector, and (ii) a second path for connecting the first path and the power storage device when the charging connector is connected to the electrically powered vehicle. The electrically powered vehicle includes a second detector for detecting a ground fault in the second path, and a second controller configured to, when the abnormality information is received from the charging facility, perform ground fault detection using the second detector after the charging connector is disconnected.

In this way, when the abnormality information is received from the charging facility, ground fault detection is performed using the second detector after the charging connector is disconnected. Accordingly, it can be distinguished whether the ground fault occurring during charging using the charging facility occurs in the electrically powered vehicle or not.

In an embodiment, the electrically powered vehicle further includes a notifier for notifying a user of information. The notifier is configured to, when the abnormality information is received, notify a user of information that varies depending on whether or not the ground fault in the second path is detected.

In this way, when the abnormality information is received, the user is notified about information that varies depending on whether a ground fault has been detected or not in the electrically powered vehicle. Accordingly, the user can be notified about appropriate information depending on whether the ground fault occurs or not in the vehicle.

An electrically powered vehicle according to another aspect of the present disclosure includes: a driving motor for driving the electrically powered vehicle; a power storage device configured to supply electric power to the driving motor; a detector for detecting a ground fault in the electrically powered vehicle; and a controller configured to perform ground fault detection using the detector. When abnormality information indicating a ground fault is received from a charging facility during charging using the charging facility, the ground fault detection is performed after the electrically powered vehicle and the charging facility are disconnected from each other, the charging facility being provided external to the electrically powered vehicle.

In this way, when the abnormality information is received from the charging facility, ground fault detection is performed using the detector after the electrically powered vehicle and the charging facility are disconnected from each other. Accordingly, it can be distinguished whether the ground fault occurring during charging using the charging facility occurs in the electrically powered vehicle or not.

In an embodiment, the electrically powered vehicle further includes a notifier for notifying a user of information. The notifier is configured to, when the abnormality information is received, notify a user of information that varies depending on whether or not the ground fault in the electrically powered vehicle is detected.

In this way, when abnormality information is received, the user is notified about information that varies depending on whether the ground fault has been detected or not in the electrically powered vehicle. Accordingly, the user can be notified about appropriate information depending on whether the ground fault occurs or not in the vehicle.

DESCRIPTION OF THE EMBODIMENTS

The embodiments of the present disclosure will be hereinafter described in detail with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference characters, and description thereof will not be repeated.

In embodiments described below, a vehicle will be described by way of example as a hybrid vehicle provided with a motor generator and an engine as a driving source, but the vehicle may be an electrically powered vehicle including at least a motor generator as a driving source.

FIG. 1is a diagram schematically showing an entire configuration of a charging system according to the present embodiment. As shown inFIG. 1, a charging system1in the present embodiment includes a vehicle2, a charging stand200, a charging cable300, and a charging connector310.

Charging stand200corresponds to a charging facility provided external to vehicle2. Charging cable300has one end connected to charging stand200and the other end provided with a charging connector310. The end of charging connector310is shaped such that it can be fitted in an inlet94provided in vehicle2. When charging connector310is connected to inlet94, a battery mounted in vehicle2(seeFIG. 2) can be charged using charging stand200. In the following description, such charging using charging stand200will be referred to as external charging.

When charging is performed using charging stand200in the state where charging connector310is connected to inlet94of vehicle2, charging stand200converts alternating-current (AC) power supplied from a power supply (seeFIG. 2) into direct-current (DC) power, and supplies the converted DC power to vehicle2through charging cable300and charging connector310. In this way, the battery mounted in vehicle2(seeFIG. 2) is charged with the DC power supplied to vehicle2.

FIG. 2is a block diagram showing a detailed configuration of charging system1according to the present embodiment. As shown inFIG. 2, vehicle2includes a first motor generator (hereinafter referred to as a first MG)10, a second motor generator (hereinafter referred to as a second MG)20, a power split device30, an engine40, driving wheels50, a power control unit (PCU)60, a battery70, a ground fault detector72, a display device80, a start switch82, a system main relay (hereinafter referred to as an SMR)90, a charging relay (hereinafter referred to as a CHR)92, an inlet94, and an electronic control unit (ECU)100.

Engine40is an internal combustion engine such as a gasoline engine and a diesel engine, and controlled based on a control signal from ECU100. Based on the state of engine40(for example, the engine rotation speed and the like), ECU100controls the fuel amount supplied to a cylinder, the fuel injection timing, the ignition timing of the fuel-air mixture inside the cylinder, and the like.

First MG10and second MG20each serve as a three-phase AC rotating electric machine, for example. First MG10and second MG20are driven by PCU60.

First MG10has a function as a generator (power generator) generating electric power using the motive power of engine40split by power split device30. The electric power generated by first MG10is supplied to battery70through PCU60. Furthermore, first MG10receives the electric power from battery70to rotate an output shaft44of engine40. Thereby, first MG10has a function as a starter for starting engine40.

Second MG20has a function as a driving motor supplying driving force to driving wheels50using at least one of the electric power stored in battery70and the electric power generated by first MG10. Furthermore, second MG20has a function as a generator for performing regenerative power generation during braking. The electric power generated by second MG20is supplied to battery70through PCU60.

Power split device30is configured to be capable of splitting the motive power generated by engine40into a path leading to driving wheels50through an output shaft52and a path leading to first MG10. Power split device30is, for example, a planetary gear mechanism including a sun gear S, a carrier CA, a ring gear R, and a pinion gear P. Sun gear S is coupled to the rotor of first MG10. Ring gear R is coupled to the rotor of second MG20. Pinion gear P engages with sun gear S and ring gear R. Carrier CA is configured to hold pinion gear P in a rotatable and revolvable manner and coupled to output shaft44of engine40. In this way, engine40, first MG10, and second MG20are mechanically connected via power split device30.

Vehicle2having such a configuration runs with the driving force output from at least one of engine40and second MG20.

PCU60converts the DC power supplied from battery70into AC power for driving first MG10and second MG20. Also, PCU60converts the AC power generated by first MG10and second MG20into DC power for charging battery70. For example, PCU60is configured to include an inverter (not shown) for DC/AC power conversion and a converter (not shown) for performing DC voltage conversion between the DC link side of the inverter and battery70.

Battery70is a rechargeable DC power supply. As battery70, secondary batteries such as a nickel-metal hydride battery and a lithium ion battery are used, for example. As described above, battery70is charged with electric power generated by first MG10and/or second MG20, and also charged with electric power supplied from charging stand200. Battery70is not limited to a secondary battery but may be a rechargeable power storage device capable of generating a DC voltage, which for example may be a capacitor and the like.

An SMR90is provided on the first power line between PCU60and battery70. In response to a control signal from ECU100, SMR90switches the state of the first power line into a conductive state (ON state) or an interrupted state (OFF state).

A CHR92is provided on the second power line that is branched from a portion of the first power line between SMR90and PCU60and connected to inlet94. In response to a control signal from ECU100, CHR92switches the state of the second power line into a conductive state (ON state) or an interrupted state (OFF state). When battery70is charged using the above-described charging stand200, for example, CHR92is switched into an ON state.

Inlet94is provided with a connection detector96. Connection detector96detects whether charging connector310has been connected to inlet94or not. When connection detector96detects that charging connector310has been connected, it transmits, to ECU100, a signal Cc showing that charging connector310has been connected. Connection detector96is implemented, for example, by a contact sensor, a configuration having a circuit resistance that is mechanically changed by connection of charging connector310to inlet94, and the like.

ECU100is configured to include a central processing unit (CPU), a memory as a storage device, an input/output buffer, and the like (which are not shown). Based on the signals from each sensor and device, and the map and the program stored in the memory, ECU100controls each of the devices to bring vehicle2into a desired driving state. The above-described control is not limited to the process by software, but can also be carried out by dedicated hardware (an electronic circuit).

ECU100serves as a controller configured to control the entire hybrid system, that is, the charged/discharged state of battery70, and the operation states of engine40, first MG10and second MG20, such that vehicle2can be operated most efficiently.

Display device80is configured, for example, by a liquid crystal display, an organic electro luminescence (EL) display, and the like. Display device80may be provided, for example, with an input device such as a touch panel. Display device80is disposed at a position where this display device can be visible to a driver, for example, at a position inside the combination meter arranged on the instrument panel. In response to a control signal from ECU100, display device80shows various pieces of information about vehicle2(for example, image information, text information and the like for calling attention to a user).

Start switch82serves as an input device for the user to perform a Ready-On operation or a Ready-Off operation. When start switch82is operated, a signal showing that start switch82has been operated is transmitted to ECU100.

The Ready-On operation is performed for starting the vehicle system (devices for causing vehicle2to travel) so as to bring vehicle2into a Ready-On state (the state where the vehicle can travel). The Ready-Off operation is performed for stopping the vehicle system so as to bring vehicle2into a Ready-Off state (the state where the vehicle cannot travel).

In the Ready-On state, ECU100having functions that are partially in an idle state is started while SMR90is turned on, so that power can be supplied to second MG20. At this time, ECU100drives second MG20such that the driving force for vehicle2is generated in accordance with the driver's accelerator pedal operation.

In the Ready-Off state, the functions of ECU100are partially brought into an idle state while SMR90is turned off, so that power cannot be supplied to second MG20. Accordingly, in the Ready-Off state, even if the driver operates the accelerator pedal, no driving force is generated for vehicle2.

When ECU100receives a signal showing that start switch82has been operated in the Ready-Off state, ECU100brings vehicle2into a Ready-On state. When ECU100receives a signal showing that start switch82has been operated in the Ready-Off state, ECU100brings vehicle2into a Ready-Off state.

Ground fault detector72detects whether a ground fault occurs or not in the charging path on the vehicle side that connects inlet94and battery70. In response to a control signal from ECU100, ground fault detector72performs ground fault detection. Ground fault detector72transmits a signal showing the detection result to ECU100.

FIG. 3is a diagram showing an example of a configuration of ground fault detector72mounted in vehicle2in the present embodiment. As shown inFIG. 3, ground fault detector72includes a battery monitoring microcomputer512and a detection circuit514.FIG. 3does not show components shown inFIG. 2other than battery70and ground fault detector72.FIG. 3also shows an insulation resistance Ri that is located between a high voltage system (PCU60, battery70and the like) of vehicle2and the body (GND).

Detection circuit514includes an oscillation circuit516serving as a signal generation unit, an amplifier circuit518, a filter circuit520, a detection resistance R1, and a capacitor C3serving as a coupling capacitor.

Oscillation circuit516is connected to one end of detection resistance R1. Based on the pulse command from battery monitoring microcomputer512, oscillation circuit516outputs a pulse signal that changes at a predetermined frequency to a connection node with one end of detection resistance R1. Detection resistance R1has the other end connected to one end of capacitor C3. Specifically, detection resistance R1is connected between oscillation circuit516and capacitor C3. Capacitor C3has the other end connected to the negative electrode line of battery70.

Amplifier circuit518is connected to a connection node e between the other end of detection resistance R1and one end of capacitor C3. Amplifier circuit518amplifies the pulse signal from connection node e, and outputs the amplified pulse signal to filter circuit520. Filter circuit520is for example a band-pass filter, and extracts a pulse signal in a prescribed frequency band from the pulse signal input from amplifier circuit518, and then outputs the extracted pulse signal to battery monitoring microcomputer512. The prescribed frequency band is set, for example, in accordance with the frequency of the pulse signal output from oscillation circuit516.

Battery monitoring microcomputer512controls oscillation circuit516. Battery monitoring microcomputer512also detects a voltage of the signal output from filter circuit520. Then, based on the detected voltage, battery monitoring microcomputer512detects a decrease in insulation resistance Ri. Battery monitoring microcomputer512includes an oscillation instruction unit526and a peak hold unit528.

Oscillation instruction unit526gives an instruction to oscillation circuit516to generate a pulse signal. Peak hold unit528detects a peak voltage (the maximum voltage) in a prescribed sampling period of the pulse signal output from filter circuit520, and transmits the detected peak voltage to ECU100as a peak value Vp. The prescribed sampling period is not particularly limited as long as it is a period in which at least the voltage corresponding to the peak of the pulse signal can be detected.

ECU100determines based on peak value Vp received from battery monitoring microcomputer512whether a ground fault is caused or not by a decrease in insulation resistance Ri.

In the normal state where a ground fault does not occur, the resulting condition is that insulation resistance Ri>>detection resistance R1. Accordingly, the peak voltage detected in peak hold unit528becomes equal to a peak voltage of the voltage of the signal output from oscillation circuit516. On the other hand, when insulation resistance Ri decreases, voltage division occurs, and the peak voltage detected in peak hold unit528decreases as compared with that in the normal state. Accordingly, when peak value Vp is smaller than a threshold value Vp(0), ECU100determines that a ground fault occurs. Threshold value Vp(0) is for example a predetermined value, and also smaller than the peak voltage observed in the state where at least a ground fault does not occur.

According to the description of the present embodiment, ECU100determines whether a ground fault has occurred or not. However, for example, battery monitoring microcomputer512may determine whether a ground fault has occurred or not.

Referring back toFIG. 2, charging stand200includes a controller202, a power converter204, a ground fault detection circuit206, and a power supply208.

Power supply208serves as an AC power supply of 100V, 200V or the like. In response to the control signal from controller202, power converter204converts the AC power supplied from power supply208into DC power.

When battery70is being externally charged using charging stand200, ground fault detection circuit206detects whether a ground fault occurs or not. Ground fault detection circuit206, for example, includes: a series circuit in which two power lines are connected to each other with two resistors having the same resistance value; and a ground line through which a connection node (a neutral point) connecting two resistors is grounded. Based on whether a ground fault current flows through the ground line or not, ground fault detection circuit206detects whether a ground fault has occurred or not. When it is detected that a ground fault has occurred (that is, a ground fault current flows through the ground line), ground fault detection circuit206transmits, to controller202, a signal showing that the ground fault has been detected.

Controller202is configured to include a CPU, a memory as a storage device, an input/output buffer, and the like (which are not shown). Based on the signals from each sensor and device, and the map and the program stored in the memory, controller202controls each of the devices to bring charging stand200into a desired operating state. The above-described control is not limited to the process by software, but can also be carried out by dedicated hardware (an electronic circuit).

In addition, charging cable300includes a communication line that is not shown. Controller202of charging stand200and ECU100of vehicle2transmits and receives information to and from each other through communication with each other via the communication line when charging connector310is connected to inlet94. Controller202and ECU100establish communication, for example, according to a prescribed communication scheme such as Controller Area Network (CAN) communication or Power Line Communication (PLC).

Furthermore, charging stand200is provided with a charge starting switch (not shown), for example. When the user operates the charge starting switch, controller202starts a charging sequence.

The following description is an example of the charging sequence performed in charging system1according to the present embodiment.

When ECU100of vehicle2detects that charging connector310has been connected to inlet94, ECU100brings each of SMR90and CHR92into an ON state, thereby allowing battery70to be chargeable.

When the user operates the charge starting switch, controller202of charging stand200starts communication with ECU100and receives battery information such as the maximum voltage and the battery capacity of battery70from the ECU100side. Also, controller202of charging stand200transmits the charger information such as the maximum voltage and the maximum current of charging stand200.

Based on the received information, each of ECU100and controller202determines whether charging can be conducted or not. When each of ECU100and controller202determines that charging can be conducted, controller202causes power converter204to operate to start charging.

When the state of charge (SOC) of battery70exceeds a threshold value, ECU100transmits a signal to controller202for requesting to stop charging. When controller202receives the signal, it stops the operation of power converter204.

ECU100estimates the SOC of battery70, for example, based on the current, the voltage, the battery temperature or the like of battery70. ECU100may estimate the open circuit voltage (OCV), for example, based on the current, the voltage and the battery temperature, and may estimate the SOC of the battery based on the estimated OCV and a prescribed map. Alternatively, ECU100may estimate the SOC of battery70, for example, by summing the charge current and the discharge current of battery70.

In charging system1having the above-described configuration, when it is detected by ground fault detection circuit206during charging of battery70using charging stand200that a ground fault has occurred, controller202of charging stand200stops charging.

However, when ground fault detection circuit206of charging stand200detects a ground fault, it cannot be distinguished whether this ground fault has occurred in charging stand200or vehicle2. This is because an electrical connection is established between charging stand200and battery70. Consequently, it cannot be distinguished whether the electrically powered vehicle can be used or not.

Thus, in the present embodiment, when ground fault detection circuit206detects a ground fault during charging of battery70mounted in vehicle2, controller202of charging stand200stops charging of battery70, and also transmits, to vehicle2, abnormality information indicating that a ground fault has been detected. When ECU100of vehicle2receives the abnormality information from charging stand200, ECU100performs ground fault detection using ground fault detector72of vehicle2after charging connector310is disconnected.

In this way, ground fault detection using ground fault detector72can be performed in the state where vehicle2is electrically separated from charging stand200. Accordingly, by distinguishing whether a ground fault has occurred or not in vehicle2, it can be distinguished whether the ground fault occurring during charging using charging stand200has occurred in vehicle2or not.

The following is an explanation about the control process performed in controller202of charging stand200with reference toFIG. 4.FIG. 4is a flowchart illustrating the control process executed by controller202of charging stand200in the present embodiment.

In step (hereinafter referred to as “S”)100, controller202determines whether charging is being conducted or not. For example, when charging connector310is connected to vehicle2and power converter204is being operated (that is, when the charging current is flowing), controller202determines that charging is being conducted. When it is determined that charging is being conducted (YES in S100), the process is advanced to S102.

In S102, controller202performs the ground fault detection process using ground fault detection circuit206. Since the method for detecting a ground fault is as described above, the detailed description thereof will not be repeated.

In S104, controller202determines whether a ground fault has been detected or not. When controller202receives, from ground fault detection circuit206, a signal showing that a ground fault has been detected, controller202determines that a ground fault has been detected. When it is determined that a ground fault has been detected (YES in S104), the process is advanced to S106.

In S106, controller202stops charging. Controller202stops the operation of power converter204to stop charging. In S108, controller202transmits, to ECU100of vehicle2, the abnormality information indicating that charging has been stopped due to detection of a ground fault.

In the flowchart inFIG. 4, when charging is not being conducted (NO in S100) or when a ground fault has not been detected (NO in S104), the process is returned to S100. For example, when it is determined that charging of battery70has normally been completed in the main routine (not shown), controller202ends the control process shown in the flowchart ofFIG. 4by the interrupting process.

Then, the control process performed by ECU100of vehicle2will be hereinafter described with reference toFIG. 5.FIG. 5is a flowchart illustrating the control process executed by ECU100of vehicle2in the present embodiment.

In S200, ECU100determines whether external charging is being conducted or not. For example, when charging connector310is connected to vehicle2, SMR90and CHR92each are in an ON state and the charging current is supplied to battery70, then, ECU100determines that external charging is being conducted. When it is determined that external charging is being conducted (YES in S200), the process is advanced to S202.

In S202, ECU100determines whether abnormality information has been received or not from charging stand200. When it is determined that the abnormality information has been received (YES in S202), the process is advanced to S204. In S204, ECU100brings each of SMR90and CHR92into an OFF state. At this time, vehicle2is brought into a Ready-Off state.

In S206, ECU100determines whether charging connector310has been disconnected or not. Based on the signal received from connection detector96, ECU100determines whether charging connector310has been disconnected or not. When it is determined that charging connector310has been disconnected (YES in S206), the process is advanced to S208.

In S208, ECU100determines whether vehicle2is in a Ready-On state or not. For example, when the operation to allow vehicle2to travel is performed (for example, the Ready-On operation is performed with start switch82), ECU100determines that vehicle2is in a Ready-On state. When it is determined that vehicle2is in a Ready-On state (YES in S208), the process is advanced to S210.

In S210, ECU100starts the ground fault detection process using ground fault detector72. Since the ground fault detection using ground fault detector72is as described above, the detailed description thereof will not be repeated.

In S212, ECU100determines whether a ground fault has occurred or not on the vehicle2side. Based on the signal received from ground fault detector72(a signal showing peak value Vp), ECU100determines that a ground fault has occurred on the vehicle2side. When it is determined that a ground fault has occurred on the vehicle2side (YES in S212), the process is advanced to S214.

In S214, ECU100performs a display process (1). The display process (1) is performed, for example, for causing display device80to show the information indicating that an abnormality occurs in vehicle2. For example, as shown inFIG. 6, ECU100causes display device80to show text information stating: “Hybrid System Check Result <Abnormality Found>”. When ECU100determines that a ground fault has occurred on the vehicle2side, it may cause display device80to show the text information shown inFIG. 6, and after that, to show the information that urges stopping of vehicle2. The text information shown inFIG. 6is merely by way of example, and not particularly limited to the contents shown inFIG. 6.

When it is determined in S212that a ground fault has not occurred on the vehicle2side (NO in S212), the process is advanced to S216.

In S216, ECU100determines whether a prescribed detection time period has elapsed or not since the ground fault detection process was started. The prescribed detection time period is a predetermined time period longer than the time period in which it can be reliably determined whether a ground fault has occurred or not on the vehicle2side since the ground fault detection process was started. When it is determined that the prescribed detection time period has elapsed since the ground fault detection process was started (YES in S216), the process is advanced to S218.

In S218, ECU100performs a display process (2). The display process (2) is performed, for example, for causing display device80to show the information indicating that an abnormality does not occur in vehicle2. Thus, the display process (2) is to give a notification about the information different from that shown in the display process (1). For example, as shown inFIG. 7, ECU100causes display device80to show the text information on the display screen stating: “Hybrid System Check Result <No Abnormality>”. The text information shown inFIG. 7is merely by way of example, and may be information different from that shown inFIG. 6, but is not particularly limited to the contents shown inFIG. 7.

Also in the flowchart inFIG. 5, when external charging is not being conducted (NO in S200), and when abnormality information is not received (NO in S202), the process is returned to S200. For example, when it is determined that external charging of battery70has normally been completed in the main routine (not shown), ECU100ends the control process shown in the flowchart ofFIG. 5by the interrupting process.

Also, when charging connector310is not disconnected in S206(NO in S206), ECU100returns the process to S206. Furthermore, when it is determined in S208that vehicle2is not in a Ready-On state (NO in S208), ECU100returns the process to S208. Also, when it is determined in S216that a prescribed detection time period has not elapsed since the ground fault detection process was started (NO in S216), ECU100returns the process to S212.

The operation of charging system1according to the present embodiment based on the above-described structures and flowcharts will be hereinafter described with reference toFIG. 8.

FIG. 8is a diagram for illustrating the operation of controller202in charging stand200and the operation of ECU100in vehicle2.

As shown inFIG. 8, when the user connects charging connector310of charging stand200to inlet94of vehicle2, ECU100of vehicle2detects that charging connector310has been connected to inlet94. When ECU100detects that charging connector310has been connected to inlet94, it brings each of SMR90and CHR92into an ON state, and then stands by.

When the user operates the charge starting switch of charging stand200, charging is started. In charging stand200, during charging (YES in S100), the ground fault detection process is performed (S102). On the other hand, in vehicle2, during external charging (YES in S200), it is determined whether the abnormality information has been received or not (S202).

In charging stand200, when occurrence of a ground fault has been detected (YES in S104), charging is stopped (S106), and the abnormality information is transmitted from controller202to ECU100(S108).

In vehicle2, when the abnormality information is received (YES in S202), SMR90and CHR92are brought into an OFF state (S204), and it is determined whether charging connector310has been disconnected from inlet94or not (S206).

The following is a description about the case where the user removes charging connector310from inlet94without noticing abnormal end of charging, and then the user gets in vehicle2. In this case, since it is detected that charging connector310has been disconnected (YES in S206), it is determined whether vehicle2is in a Ready-On state or not (S208).

When vehicle2is brought into a Ready-On state (YES in S208) by the user operating start switch82after the user gets in vehicle2, ground fault detection using ground fault detector72is started (S210). Then, it is determined whether a ground fault has occurred or not on the vehicle side (S212).

When it is determined that a ground fault has occurred on the vehicle2side (YES in S212) by the time when a prescribed detection time period has elapsed (NO in S216), the display process (1) is performed (S214). Thereby, the text information shown inFIG. 6is to be displayed on the display screen of display device80.

When occurrence of a ground fault has been detected in vehicle2, vehicle2is stopped and the Ready-Off operation is performed, and after that, the Ready-On operation is not allowed to be accepted, for example. In this way, it is desirable to suppress traveling of vehicle2.

On the other hand, when a prescribed detection time period has elapsed (YES in S216) without detection of a ground fault (NO in S212), the display process (2) is performed (S218). Thereby, the text information shown inFIG. 7is to be displayed on the display screen of display device80. Also, since a ground fault is not detected, vehicle2can still be used.

As described above, according to the charging system in the present embodiment, when ECU100of vehicle2receives the abnormality information from controller202of charging stand200, ECU100performs ground fault detection using ground fault detector72after charging connector310is disconnected. Thus, it can be distinguished whether the ground fault occurring during charging using charging stand200occurs in vehicle2or not. Therefore, it becomes possible to provide a charging system and an electrically powered vehicle, by which it is distinguished whether a vehicle can be used or not when a ground fault occurs during charging of the power storage device mounted in the vehicle using a charging facility external to the vehicle.

Furthermore, the convenience of vehicle2can be improved by determined whether vehicle2can be used or not. For example, even when a ground fault is detected during charging using charging stand200, but when this detected ground fault does not occur in vehicle2, the user can use vehicle2without limitation.

Furthermore, when a ground fault occurs on the vehicle2side, for example, it is displayed that an abnormality has occurred in a hybrid system, thereby giving a notification about the information that varies depending on whether a ground fault has been detected or not in vehicle2. Thus, the user can be notified about appropriate information depending on whether the ground fault occurs or not in vehicle2.

In the following, modifications will be described.

In the above embodiments, the display process (1) and the display process (2) each have been described as a process in which predetermined text information is displayed on display device80. However, in place of such text information, image information such as illustrations, icons or warning lights may be displayed on display device80. For example, in the display process (1), the image information urging re-connection of charging connector310may be displayed. In the display process (2), the image information urging stopping of vehicle2may be displayed.

In the above embodiments, the display process (1) and the display process (2) each have been described as a process in which the user is notified about the information by displaying information on display device80. However, the user may be notified about the information, for example, by a voice and a warning sound in a prescribed pattern issued through a speaker and the like in place of using display device80.

Furthermore, in the above embodiments, charging stand200has been described as being configured to convert the AC power of power supply208into DC power using power converter204, and supply the converted DC power to vehicle2. However, charging stand200may be configured to supply the AC power of power supply208to vehicle2. In this case, the power converter for converting AC power into DC power is provided on the vehicle2side, and this power converter converts the AC power supplied from charging stand200into DC power, thereby charging battery70.

Furthermore, according to the description in the above embodiments, the ground fault detection method by ground fault detection circuit206in charging stand200and the ground fault detection method by ground fault detector72in vehicle2are different. However, the ground fault detection method on the charging stand200side may be the same as the ground fault detection method on the vehicle2side, or the ground fault detection method on the vehicle2side may be the same as the ground fault detection method on the charging stand200side.

Furthermore, according to the description in the above embodiments, after the abnormality information is received and charging connector310is disconnected, vehicle2is brought into a Ready-On state, and then, the display process (1) is performed. However, for example, the display process (1) may be performed when start switch82is operated.

Furthermore, according to the description in the above embodiments, controller202of charging stand200starts charging when the user operates the charge starting switch in charging stand200. However, for example, controller202may measure the time using a timer and start charging at the time when the measured time becomes equal to the prescribed charging start time.

The above-described modifications may be performed while being wholly or partially combined as appropriate.