JP2018007471A - Electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the possibility that, with respect to an electric automobile provided with a PCU (Power Control Unit) 10 having a smoothing capacitor, at the time of a collision, although a discharge circuit for discharging the smoothing capacitor is alive, a host controller 7 determines the PCU 10 to be low in reliability and stops transmission of a discharge command.SOLUTION: An electric automobile 2 comprises a PCU 10 having a MG controller 12, and a host controller 7 communicating with the PCU 10. The MG controller 12 transmits a reset signal to the host controller 7 when a malfunction occurs but the function returns. The host controller 7 counts the number of times of receiving the reset signal from the MG controller 12, and after reception of a collision signal, when the number of times of reception counted until transmission of a discharge command is equal to or more than a predetermined number, stops transmission of the discharge command. The host controller 7 monitors the voltage of a power line 21 and does not count the reset signal accompanying a voltage drop and a recovery of the power line 21 as the number of times of reception.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric vehicle. The “electric vehicle” in this specification includes a hybrid vehicle including both a motor and an engine, and an electric vehicle using a fuel cell as a power source.

  An electric vehicle includes a power control unit that converts power from a power source such as a battery or a fuel cell into driving power for a traveling motor (for example, Patent Document 1). The power control unit of Patent Document 1 includes a capacitor (smoothing capacitor) that smoothes the voltage (current) of the power supply. The voltage of the power supply exceeds 100 volts and the current reaches tens of amperes. In order to smooth such a large power voltage (current), a large capacity capacitor is used. Since a large amount of electric power is stored in the smoothing capacitor, it is desirable to discharge the smoothing capacitor quickly when the vehicle collides. The power control unit of Patent Document 1 includes a discharge circuit that discharges a smoothing capacitor. When the host controller of the power control unit receives a collision detection signal from the airbag sensor, it transmits a discharge command to the power control unit. There is a local controller in the power control unit, and the local controller receives a discharge command from the host controller and drives the discharge circuit.

JP 2012-090424 A

  By the way, many in-vehicle devices (especially devices having a controller) are connected so as to be able to communicate with each other, and other devices in which communication failure has occurred with a specific device have problems with the specific device. It determines that it has occurred and switches itself to a mode that does not use that particular device. Alternatively, when a failure occurs in some devices, a failure occurrence signal that notifies the failure is transmitted to other devices. The other device that has received the failure occurrence signal switches itself to a mode that does not use the device that has transmitted the failure occurrence signal. A device whose function has been recovered by solving the problem (a device whose communication has been recovered) transmits a reset signal notifying that the function has been recovered to another device. Other devices that receive the reset signal can use the recovered device again.

  If a reset signal is transmitted many times from one device, the reliability of the reset signal itself becomes suspicious. Therefore, the in-vehicle device is provided with a function (low reliability device exclusion function) that prevents a device that has transmitted a reset signal more than a predetermined number of times from being regarded as having low reliability. The power control unit and the host controller that sends a command to the power control unit have a low-reliability device exclusion function.

  During normal driving, the reliability of the entire vehicle is maintained by the low-reliability device exclusion function. When the host controller receives a reset signal more than a predetermined number of times from the local controller of the power control unit at the time of collision, the host controller does not issue a discharge command due to the low reliability device exclusion function. In the event of a collision, there is a possibility that a reset signal may be output due to various factors. However, unlike during driving, if there is a possibility that the discharge circuit can be used, a discharge command is sent from the host controller to the local controller of the power control unit It is desirable to do. In this specification, in the case of a collision in which a reset signal can be generated many times, a reset signal for a failure that is highly likely to be usable can be ignored, and the power control unit can discharge as much as possible. Provide technology.

  A typical occurrence of a reset signal that can occur in the event of a collision is when a short circuit occurs in another device sharing the power line that supplies power to the local controller of the power control unit, causing the voltage of the power line to temporarily drop. The power source here is a low voltage power source for driving the local controller of the power control unit, which is different from the high voltage power source for driving the motor. Hereinafter, in order to distinguish between them, the power source for driving the motor is referred to as a main power source, and the power source for driving the local controller, the host controller, etc. and having a lower voltage than the main power source is referred to as a sub power source.

  When the voltage of the power line of the sub power supply decreases, the local controller of the power control unit becomes unstable in operation and transmits a failure occurrence signal. Alternatively, the local controller may not be able to normally communicate with the host controller due to the unstable operation of the voltage drop of the power line. In that case, the host controller determines that a failure has occurred in the local controller. When the fuse blows in the device that caused the short circuit, the voltage of the power line is restored, and the function of the local controller of the power control unit is restored. The local controller of the power control unit transmits a reset signal. Since a plurality of devices including the power control unit are connected to the power line of the sub power source, a voltage drop and recovery of the power line occur each time the device is short-circuited and the fuse is blown. A reset signal is transmitted from the local controller of the power control unit every time the power line voltage drops and recovers. The reset signal is transmitted from the local controller of the power control unit as many as the number of short-circuited devices. In this case, there is a high possibility that the discharge circuit of the power control unit is safe. However, if the low-reliability device removal function is activated as in traveling, the host controller may not issue a discharge command to the power control unit. The host controller of the electric vehicle disclosed in this specification does not count the reset signal that accompanies voltage line voltage drop and recovery as the number of receptions. By this process, the possibility that the host controller stops transmission of the discharge command by the low reliability device exclusion function can be reduced, and the smoothing capacitor can be discharged by the power control unit as much as possible.

  One aspect of the electric vehicle disclosed in this specification includes a main power source, a sub power source, a power control unit, and a host controller. The power control unit converts the power of the main power source into drive power for the travel motor. The power control unit includes a capacitor that smoothes the current of the main power supply, a discharge circuit that discharges the capacitor, and a local controller that controls the discharge circuit. The sub power supply supplies power having a voltage lower than that of the main power supply to the local controller of the power control unit via the power line. When the host controller receives a collision signal from the collision detection sensor, the host controller transmits a discharge command for discharging the capacitor to the local controller of the power control unit. The local controller of the power control unit transmits a reset signal to the host controller when the malfunction is resolved and the function is restored after the malfunction occurs in the power control unit. The host controller counts the number of times the reset signal is received from the local controller of the power control unit, and when the number of times received until the discharge command is transmitted after the collision signal is received is greater than or equal to the predetermined number, It has an unreliable device exclusion function that stops transmission. The host controller monitors the voltage of the power line. After receiving the collision signal, the host controller does not count the reset signal that accompanies the voltage drop and recovery of the power line.

  The above-described electric vehicle does not count the reset signal that is highly likely to maintain the discharge function at the time of a collision. Thus, the possibility that the host controller stops the transmission of the discharge command by the unreliable device exclusion function is reduced, and the power control unit discharges the smoothing capacitor as much as possible. Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a block diagram of the electric power system of the electric vehicle of an Example. FIG. 2A is a flowchart of reset signal count processing at the time of collision. FIG. 2B is a flowchart of the unreliable device exclusion process at the time of collision. It is a time chart of the process of the high-order controller at the time of a collision. FIG. 3A shows a change in the collision detection signal. FIG. 3B shows a change in voltage of the power line being monitored. FIG. 3C shows a change in the received reset signal. FIG. 3D shows a change in the number of receptions counted. FIG. 3E shows changes in the discharge command signal.

  An electric vehicle 2 according to an embodiment will be described with reference to the drawings. In FIG. 1, the block diagram of the electric power system of the electric vehicle 2 is shown. The electric vehicle 2 according to the embodiment includes a main battery 3, a sub battery 6, a power control unit 10, a traveling motor 5, a host controller 7, an airbag controller 8, an airbag sensor 9, and auxiliary machine groups 30 a to 30 c. The power control unit 10 is a device that converts DC power of the main battery 3 into driving power of the motor 5 for traveling. Below, in order to simplify description, the power control unit 10 is referred to as a PCU 10 (Power Control Unit).

The PCU 10 includes a voltage converter circuit 13, an inverter circuit 14, smoothing capacitors 15 and 16, and an MG controller 12. The voltage converter circuit 13 boosts the DC power of the main battery 3 and supplies the boosted DC power to the inverter circuit 14. The inverter circuit 14 converts the supplied DC power into three-phase AC power suitable for driving the motor 5 and supplies it to the motor 5. A smoothing capacitor 15 is connected in parallel before the voltage converter circuit 13, and a smoothing capacitor 16 is connected in parallel between the voltage converter circuit 13 and the inverter circuit 14. The smoothing capacitors 15 and 16 are provided for smoothing the voltage (current) of the main battery 3. The maximum output of the main battery 3 is, for example, 300 volts and 30 amps. As the smoothing capacitors 15 and 16 for smoothing such a large power voltage (current), those having a large capacity are employed. It is desirable that the smoothing capacitors 15 and 16 that store a large amount of electric power be discharged quickly in the event of a vehicle collision.

  The voltage converter circuit 13 and the inverter circuit 14 include a number of power conversion transistors. Those transistors are controlled by the MG controller 12. That is, the MG controller 12 controls the voltage converter circuit 13 and the inverter circuit 14. In the event of a collision, the MG controller 12 receives the discharge command from the host controller 7 and discharges the smoothing capacitors 15 and 16 using the voltage converter circuit 13 and the inverter circuit 14. Specifically, the voltage converter circuit 13 includes a reactor, and the MG controller 12 controls the transistors of the voltage converter circuit 13 so that a part of the electric power stored in the smoothing capacitors 15 and 16 flows to the reactor. To do. Part of the electric energy stored in the smoothing capacitors 15 and 16 is consumed by the heat generation and loss of the reactor. Further, the MG controller 12 controls the transistor of the inverter circuit 14 so that the remainder of the electric power stored in the smoothing capacitors 15 and 16 is supplied to the motor 5. At that time, the MG controller 12 controls the transistor of the inverter circuit 14 so as to output a three-phase alternating current that does not rotate the motor 5. The remainder of the electrical energy stored in the smoothing capacitors 15 and 16 is consumed by the heat generation and loss of the coil of the motor 5. Normally, the voltage converter circuit 13 that generates the driving power of the motor 5 and the inverter circuit 14 function as a discharge circuit when a collision occurs.

  The MG controller 12 of the PCU 12 normally controls the voltage converter circuit 13 and the inverter circuit 14 so as to convert the power of the main battery 3 into the driving power of the motor 5. When receiving the discharge command from the host controller 7, the MG controller 12 controls the voltage converter circuit 13 and the inverter circuit 14 so as to discharge the smoothing capacitors 15 and 16, as described above.

  The host controller 7 and the PCU 10 (MG controller 12) are connected by a communication line 22 and can communicate with each other. The host controller 7 calculates a target output of the motor 5 based on the accelerator opening and the remaining amount of the main battery 3 during traveling, and transmits the target output to the MG controller 12. When the host controller 7 receives a signal indicating that the vehicle has collided from the airbag sensor 9 via the airbag controller 8, it sends a discharge command for discharging the smoothing capacitors 15 and 16 to the MG of the PCU 10 via the communication line 22. Transmit to the controller 12. The airbag sensor 9 is an acceleration sensor, and when detecting an acceleration comparable to a vehicle collision, the airbag sensor 9 transmits a signal (collision detection signal) notifying the fact (that is, a collision of the vehicle) to the airbag controller 8. When the airbag controller 8 receives the collision detection signal, the airbag controller 8 inflates an airbag (not shown) and transfers the collision detection signal to the host controller 7.

  A system main relay 4 is connected between the main battery 3 and the PCU 12. In the event of a collision, the host controller 7 opens the system main relay 4 and disconnects between the main battery 3 and the PCU 10. At the time of a collision, the main battery 3 is disconnected from the PCU 10, whereby the power supply to the smoothing capacitors 15 and 16 is stopped, and the smoothing capacitors 15 and 16 can be discharged.

  The host controller 7, the air bag controller 8, and the MG controller 12 of the PCU 10 operate at a voltage lower than the voltage of the main battery 3. The sub battery 6 supplies power to the host controller 7, the air bag controller 8, and the MG controller 12 of the PCU 10. For example, the voltage of the sub battery 6 is 14 volts with respect to the voltage of the main battery 3 exceeding 100 volts. The sub battery 6, the host controller 7, the air bag controller 8, and the MG controller 12 of the PCU 10 are connected by a power line 21. The power line 21 and the host controller 7 are connected via a fuse 23. The host controller 7 and the air bag controller 8 are also connected to the power line 21 via the fuse 23. Power is supplied from the sub-battery 6 to the host controller 7 and the like via the power line 21. The MG controller 12 of the PCU 10 is also connected to the power line 21 via the fuse 23.

  Other auxiliary machine groups 30 a to 30 c are also connected to the power line 21. “Auxiliary equipment” is a generic term for devices that operate on the voltage of the sub-battery 6. Room lamps, headlamps, audio, navigation devices, radios, wipers, air purifiers, etc. correspond to auxiliary equipment. In FIG. 1, the auxiliary machine indicated by reference numeral 30a is referred to as a first auxiliary machine, the auxiliary machine indicated by reference numeral 30b is referred to as a second auxiliary machine, and the auxiliary machine indicated by reference numeral 30c is referred to as a third auxiliary machine. Each of the auxiliary machine groups 30 a to 30 c is also connected to the power line 21 via the fuse 23. The host controller 7, the air bag controller 8, and the MG controller 12 of the PCU 10 also correspond to “auxiliary machines”. The negative electrode of the sub-battery 6 is connected to the ground, and the power negative electrode end of each auxiliary machine is also connected to the ground (not shown). Therefore, in FIG. 1, the sub-battery 6 and each auxiliary machine are drawn so as to be connected by only one power line 21 (positive power line).

  When the auxiliary machine is short-circuited, the voltage of the power line 21 is reduced, but when an overcurrent flows to the short-circuited auxiliary machine, the fuse 23 is blown. When the fuse 23 between the short-circuited auxiliary machine and the power line 21 is blown, the short-circuited auxiliary machine is disconnected from the power line 21 and the voltage of the power line 21 is recovered.

  From here, the low reliability device exclusion function will be described. The PCU 10 and some auxiliary devices (devices) transmit a signal indicating the occurrence of a failure (failure occurrence signal) to the host controller 7 when a failure occurs inside. Further, when the host controller 7 detects an abnormality in communication with another auxiliary machine, it determines that a malfunction has occurred in the partner auxiliary machine. The MG controller 12 of the PCU 10 becomes unstable when other auxiliary devices are short-circuited and the voltage of the power line 21 is lowered, and communication with the host controller 7 is not normal. When the host controller 7 detects an abnormality in the communication between the PCU 10 and the MG controller 12, the host controller 7 determines that a problem has occurred in the MG controller 12, and switches to a mode in which the MG controller 12 (PCU 10) is not used. Alternatively, the MG controller 12 transmits a failure occurrence signal to the host controller 7 when the temperature of the transistors of the voltage converter circuit 13 and the inverter circuit 14 is equal to or higher than a threshold value. When the host controller 7 receives the failure occurrence signal from the MG controller 12, the host controller 7 switches to a mode in which the PCU 10 is not used.

  Depending on the type of fault, the fault may be resolved and the auxiliary machine may restore its function. The auxiliary machine whose function has been recovered after the occurrence of a failure transmits a signal (reset signal) for notifying the host controller 7 of the function recovery. When the host controller 7 receives the reset signal, the host controller 7 again uses the auxiliary equipment that has transmitted the reset signal. For example, the MG controller 12 transmits a reset signal to the host controller 7 when the transistor temperature returns to the normal range after detecting a transistor overheat and transmitting a failure occurrence signal. Alternatively, when recovery is performed after the voltage of the power line 21 is lowered due to short-circuiting of another auxiliary machine and blown fuse, the MG controller 12 recovers after operation instability due to the voltage drop and transmits a reset signal to the host controller 7. The host controller 7 that has received the reset signal from the MG controller 12 uses the MG controller 12 (PCU 10) again.

  The host controller 7 counts the number of times the reset signal is received from the same auxiliary machine, and if the reset signal is received three or more times from the same auxiliary machine within a predetermined period, even if the reset signal is received, The accessory is not used because of its low reliability. This function is referred to as an unreliable device exclusion function. During normal traveling, the host controller 7 switches to a mode in which the PCU 10 is not used when receiving a reset signal three or more times within a predetermined period from the MG controller 12 of the PCU 10.

  Next, the relationship between the discharge of the smoothing capacitors 15 and 16 at the time of collision and the low reliability device exclusion function will be described. As described above, when receiving the collision signal, the host controller 7 transmits a discharge signal to the MG controller 12 of the PCU 10. However, if the reset signal has been received three or more times from the MG controller 12 before the discharge signal is transmitted, the host controller 7 operates the unreliable device exclusion function and stops transmitting the discharge signal. However, after the collision, there is a possibility that a short circuit and a fuse cut may occur in many auxiliary machines, and the reset signal accompanying the voltage drop and voltage recovery of the power line 21 described above may be transmitted several times from the MG controller 12. There is. There is a high possibility that the malfunction of the MG controller 12 due to the voltage drop of the power line 21 does not impair the discharge function. That is, even if the reset signal resulting from the voltage drop and recovery of the power line 21 is received a plurality of times, there is a high possibility that the discharge function of the PCU 12 is alive. Therefore, the host controller 7 monitors the voltage of the power line 21 and, after receiving the collision signal, does not count the reset signal accompanied by the voltage drop and recovery of the power line 21 as the number of receptions. As a result of this processing, the number of receptions of the reset signal from the MG controller 12 after the collision (the number of receptions counted) does not increase due to a short circuit of another auxiliary machine or a blown fuse. The low reliability device exclusion function does not work for the MG controller 12 due to a short circuit of another auxiliary machine and a blown fuse. Therefore, the host controller 7 is less likely to stop sending the discharge command to the MG controller 12. The electric vehicle 2 ignores a reset signal (a reset signal due to a voltage drop and recovery caused by a short circuit of another auxiliary machine and a blown fuse) and a discharge to the PCU 10 for a malfunction that is likely to maintain a discharge function. Increase the likelihood of implementation.

  The above processing will be described again with reference to the flowchart of FIG. FIG. 2A is a flowchart of reset signal counting processing by the host controller 7. Normally, when the host controller 7 receives a reset signal from the MG controller 12 of the PCU 10, it counts up the number of times the reset signal is received (S2: NO, S4). On the other hand, when the host controller 7 monitors the voltage of the power line 21 and has already received a collision detection signal, and receives a reset signal almost simultaneously with the voltage drop and recovery of the power line 21, the reception is counted. Without holding the number of receptions. That is, after receiving the collision detection signal, the host controller 7 does not count the reset signal accompanied by the voltage drop and recovery of the power line 21 (S2: YES, S3: YES, S5). Even after receiving the collision detection signal, the host controller 7 counts the number of receptions of the reset signal that is not accompanied by the voltage drop and recovery of the power line 21 (S2: YES, S3: NO, S4). With the processing in FIG. 3A, after the collision signal is detected, the number of receptions does not increase with the reset signal accompanied by the voltage drop and recovery of the power line 21.

  FIG. 2B is a flowchart when the low-reliability device exclusion process is applied to the discharge command transmission after the collision. The host controller 7 counts the number of times the reset signal is received from the MG controller 12 of the PCU 10. When the number of receptions counted after transmission of the collision signal until transmission of the discharge signal is less than 3, a discharge command is transmitted (S12: NO, S13). On the other hand, if the number of receptions counted until the transmission of the discharge command after receiving the collision signal is 3 or more, the host controller 7 stops the transmission of the discharge command (S12: YES, S14). If the counted number of receptions is 3 or more from the reception of the collision detection signal to the transmission of the discharge command, the host controller 7 stops the transmission of the discharge command because the PCU 10 has low reliability. However, the host controller 7 transmits a discharge command to the MG controller 12 of the PCU 10 even if a reset signal accompanied by a voltage drop and recovery of the power line 21 is received a plurality of times by the process of FIG. 2A and 2B increases the possibility that the smoothing capacitors 15 and 16 can be discharged by the PCU 10 in the event of a collision.

  FIG. 3 shows a time chart of processing of the host controller 7 at the time of collision. FIG. 3A shows changes in the received collision detection signal. FIG. 3B shows a change in the voltage of the power line 21 being monitored. FIG. 3C shows a change in the received reset signal. FIG. 3D shows a change in the counted number of receptions. FIG. 3E shows changes in the discharge command signal. The horizontal axis indicates time. It is assumed that the host controller 7 receives a collision detection signal from the airbag sensor 9 (airbag controller 8) at time T1 (arrow Pa).

  As shown in FIG. 1, a plurality of auxiliary machines 30a-30c are connected to the power line 21 of the sub-battery 6, and some of these auxiliary machines may be short-circuited due to the impact of a collision. Since an overcurrent flows when the auxiliary machine is short-circuited, the fuse 23 associated with the auxiliary machine is blown. When the auxiliary machine is short-circuited, the voltage of the power line 21 decreases, but when the fuse is blown, the voltage of the power line 21 is recovered. The locations indicated by the arrows Pb and Pc in FIG. 3 represent the voltage drop of the power line 21 caused by a short circuit of the auxiliary machine and a blown fuse and the recovery thereof. When the voltage of the power line 21 decreases and the MG controller 12 malfunctions and the voltage of the power line 21 recovers, the MG controller 12 recovers its function and transmits a reset signal. The reset signal indicated by the arrow Pd is a reset signal transmitted due to the voltage drop and recovery indicated by the arrow Pb. The reset signal indicated by the arrow Pe is a reset signal transmitted due to the voltage drop and recovery indicated by the arrow Pc. Since the host controller 7 does not count the reset signal that accompanies the voltage drop and recovery of the power line 21, as shown in FIG. 3D, the number of receptions does not increase with respect to the reset signals of the arrows Pd and Pe. For example, when the transistor of the inverter circuit 14 is overheated, the MG controller 12 transmits a failure occurrence signal to the host controller 7. When the overheating of the transistor is resolved, the MG controller 12 transmits a reset signal to the host controller 7. In response to such a reset signal (for example, arrow Pf in FIG. 3) that is not accompanied by voltage drop and recovery of the power line 21, the host controller 7 counts up the number of receptions (arrow Pg in FIG. 3). In the example of FIG. 3, the reset signal is transmitted three times from the reception of the collision detection signal, but the host controller 7 counts only one of them as the number of receptions. As a result, the number of receptions counted until transmission of the discharge signal is less than 3, and the host controller 7 transmits a discharge command signal at time T6 (arrow Ph).

  For example, 100 [msec] is required from the reception of the collision detection signal to the transmission of the discharge command. For example, 100 [msec] is from time T1 to time T6 in FIG. Various things happen instantaneously at the time of a collision. For example, there is a possibility that a short circuit and a fuse cut may occur in a plurality of auxiliary machines during 100 [msec], or a temperature sensor of the transistor of the PCU 10 may break down and temporarily transmit a signal indicating that the transistor is overheated.

  As described above, after receiving the collision signal, the host controller 7 of the electric vehicle 2 according to the embodiment counts the reset signal accompanying the voltage drop and recovery of the power line 21 that supplies power to the MG controller 12 to the number of receptions. do not do. Such a process can increase the possibility that the smoothing capacitors 15 and 16 can be discharged by the PCU 10 in the event of a collision.

  Points to be noted regarding the technology described in the embodiments will be described. In the embodiment, the discharge of the smoothing capacitors 15 and 16 when the MG controller 12 transmits a reset signal not accompanied by a voltage drop and recovery of the power line 21 three times or more after the collision is not mentioned. The electric vehicle 2 preferably has a backup discharge circuit in case the smoothing capacitors 15 and 16 cannot be discharged by the PCU 10. In the embodiment, the threshold of the number of reception times of the unreliable device exclusion process is three times. The threshold value of 3 times is an example, and the threshold value may be 2 times or 4 times or more.

  The MG controller 12 of the embodiment corresponds to an example of “local controller” in the claims. The main battery 3 of the embodiment corresponds to an example of “main power supply” in the claims. The main power source may be a fuel cell. The airbag sensor 9 according to the embodiment corresponds to an example of a “collision detection sensor” in the claims. The collision detection sensor is not limited to the airbag sensor 9 (acceleration sensor). The collision detection sensor may be a sensor that transmits a signal indicating that a collision with an obstacle ahead is inevitable. The voltage converter circuit 13 and the inverter circuit 14 that are used as devices for discharging the smoothing capacitors 15 and 16 in the event of a collision correspond to an example of the “discharge circuit” in the claims.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Electric vehicle 3: Main battery 4: System main relay 5: Motor 6: Sub battery 7: Host controller 8: Air bag controller 9: Air bag sensor 10: Power control unit (PCU)
12: MG controller 13: voltage converter circuit 14: inverter circuit 15, 16: smoothing capacitor 21: power line 22: communication line 23: fuse 30a-30c: auxiliary equipment

Claims (1)

A power control unit that converts electric power of a main power source into driving power of a traveling motor, a capacitor that smoothes the current of the main power source, a discharge circuit that discharges the capacitor, and a local controller that controls the discharge circuit A power control unit comprising:
A sub power supply that supplies power to the local controller via a power line at a voltage lower than that of the main power supply;
When a collision signal is received from a collision detection sensor, a host controller that transmits a discharge command for discharging the capacitor to the local controller;
With
The local controller transmits a reset signal to the host controller when the malfunction is resolved and the function is restored after the malfunction occurs in the power control unit,
The host controller is
Counts the number of times the reset signal is received from the local controller, and stops sending the discharge command when the number of times counted until the discharge command is transmitted after the collision signal is received is greater than or equal to a predetermined number. Has a function to exclude unreliable devices,
An electric vehicle characterized in that the voltage of the power line is monitored, and after receiving the collision signal, a reset signal accompanied by a voltage drop and recovery of the power line is not counted in the number of receptions.

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