JP2009130940A - Electric vehicle, residual charge discharging method, and computer-readable recording medium recording a program for causing a computer to execute the discharging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle which can discharge residual charges of a capacitor provided in a pair of power lines receiving charging power from a power supply on the outside of the vehicle. <P>SOLUTION: A discharge control section determines whether such a state as the absolute value of a voltage VAC is more than a predetermined threshold has continued or not (S50) after ending the charging operation of an energy storage device from a power supply on the outside of the vehicle. If a determination is made that the state has continued (YES at S50), the discharge control section turns a DFR on (S70) after ending the discharge operation of first and second capacitors (YES at S60). When the residual charges of a third capacitor are discharged by a first discharge resistor and the absolute value of a voltage VAC becomes smaller than a threshold (YES at S80), the discharge control section turns the DFR off (S90). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to discharge control of residual charges in an electric vehicle capable of charging a power storage device capable of storing electric power for vehicle travel from a power source external to the vehicle.

  Japanese Patent No. 2695083 (Patent Document 1) discloses an electric motor drive and power processing apparatus capable of transferring power between an AC power supply outside a vehicle and an in-vehicle DC power supply. This apparatus comprises a DC power supply, two inverters, two induction motors, a control unit, an input / output port, and an EMI filter. Each induction motor includes a Y-connected winding, and an input / output port is connected to the neutral point of each winding.

  In this device, in the recharging mode, the DC power can be charged by converting the AC power applied to the neutral point of each winding from the single-phase power connected to the input / output port into DC power. Further, it is possible to generate sine wave-adjusted AC power between the neutral points of each winding and output the generated AC power to an external device connected to the input / output port.

The EMI filter is provided between the neutral point of each winding and the input / output port, and reduces high-frequency noise appearing at the input / output port (see Patent Document 1).
Japanese Patent No. 2695083 JP 2003-230269 A

  In the above-mentioned Japanese Patent No. 2695083, the detailed configuration of the EMI filter provided between the neutral point of each winding and the input / output port is not disclosed, but in general, such a filter is not disclosed. In order to reduce normal mode noise, a capacitor provided between the power lines and a discharge resistor connected in parallel to the capacitor and capable of discharging the residual charge of the capacitor are provided.

  When the discharge resistor is disconnected, the residual charge of the capacitor cannot be discharged. However, the above publication does not discuss such a problem at all.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric vehicle capable of reliably discharging the residual charge of a capacitor provided in a power line pair that receives charging power from a power source outside the vehicle.

  Another object of the present invention is to provide a discharging method capable of reliably discharging the residual charge of a capacitor provided in a power line pair that receives charging power from a power source outside the vehicle, and a program for causing a computer to execute the discharging method. It is to provide a recorded computer-readable recording medium.

  According to the present invention, the electric vehicle is an electric vehicle capable of charging a power storage device capable of storing electric power for driving the vehicle from a power source outside the vehicle, the first and second AC motors, the power conversion circuit, A discharge unit, a power reception unit, a power line pair, a relay, a first capacitor, a first discharge resistor, and a control device. The first AC motor includes a first multiphase winding connected in a star shape as a stator winding. The second AC motor includes a second multiphase winding connected in a star shape as a stator winding. The power conversion circuit is provided between the power storage device and the first and second AC motors. The discharge unit is configured to be able to discharge the residual charge of the power conversion circuit. The power receiving unit is configured to receive power supplied from a power source outside the vehicle. The power line pair is disposed between the power reception unit and the neutral point of the first multiphase winding and between the power reception unit and the neutral point of the second multiphase winding. The relay is provided on the power line pair, and electrically connects the power receiving unit to each neutral point when the power storage device is charged from the power source outside the vehicle, and connects the power receiving unit to each neutral point when the power storage device is not charged from the power source outside the vehicle. Electrically disconnect from the neutral point. The first capacitor is connected between the power line pair between the relay and the power receiving unit. The first discharge resistor is connected in parallel to the first capacitor between the relay and the power receiving unit. The control device outputs a connection command to the relay when charging the power storage device from a power supply outside the vehicle, and converts the power given to each neutral point from the power receiving unit to charge the power storage device so as to charge the power storage device. And outputs a disconnect command to the relay when the power storage device is not charged from a power source outside the vehicle. Then, when the residual charge of the first capacitor cannot be discharged by the first discharge resistor during non-charging, the control device outputs a connection command to the relay so as to discharge the residual charge by the discharge unit.

  Preferably, when the residual charge of the first capacitor cannot be discharged, the control device outputs a connection command to the relay after the discharge unit discharges the residual charge of the power conversion circuit.

  Preferably, the power conversion circuit includes first and second inverters and a second capacitor. The first and second inverters are provided corresponding to the first and second AC motors, respectively. The second capacitor is connected between a pair of DC power lines connected to the first and second inverters. The discharge unit includes a second discharge resistor connected in parallel to the second capacitor.

  Preferably, the discharge unit includes an auxiliary device connected to the power conversion circuit. The control device outputs a connection command to the relay and an operation command to the auxiliary device when the residual charge of the first capacitor cannot be discharged.

  Preferably, the power conversion circuit includes first and second inverters and a second capacitor. The first and second inverters are provided corresponding to the first and second AC motors, respectively. The second capacitor is connected between a pair of DC power lines connected to the first and second inverters. The discharge unit is a first multiphase winding of the first AC motor and a second multiphase winding of the second AC motor. The control device outputs a connection command to the relay when the residual charge of the first capacitor cannot be discharged, and outputs each neutral point, the first and second multiphase windings, and the first and second inverters. After the residual charge of the first capacitor moves from the first capacitor to the second capacitor via the first, the disconnection command is output to the relay, and the first and second multiphase windings output the first command. At least one of the first and second inverters is controlled so as to discharge the accumulated charge of the two capacitors.

  More preferably, the control device outputs a connection command to the relay until the voltage between the power line pair falls below a specified value, and disconnects the relay after the residual charge has moved from the first capacitor to the second capacitor. The output of the command and the control of at least one of the first and second inverters are sequentially repeated.

  According to the present invention, the residual charge discharging method is a residual charge discharging method in an electric vehicle capable of charging a power storage device capable of storing electric power for vehicle travel from a power source external to the vehicle. The electric vehicle includes first and second AC motors, a power conversion circuit, a discharge unit, a power reception unit, a power line pair, a relay, a first capacitor, a first discharge resistor, and a control device. Is provided. The first AC motor includes a first multiphase winding connected in a star shape as a stator winding. The second AC motor includes a second multiphase winding connected in a star shape as a stator winding. The power conversion circuit is provided between the power storage device and the first and second AC motors. The discharge unit is configured to be able to discharge the residual charge of the power conversion circuit. The power receiving unit is configured to receive power supplied from a power source outside the vehicle. The power line pair is disposed between the power reception unit and the neutral point of the first multiphase winding and between the power reception unit and the neutral point of the second multiphase winding. The relay is provided on the power line pair, and electrically connects the power receiving unit to each neutral point when the power storage device is charged from the power source outside the vehicle, and connects the power receiving unit to each neutral point when the power storage device is not charged from the power source outside the vehicle. Electrically disconnect from the neutral point. The first capacitor is connected between the power line pair between the relay and the power receiving unit. The first discharge resistor is connected in parallel to the first capacitor between the relay and the power receiving unit. The control device outputs a connection command to the relay when charging the power storage device from a power supply outside the vehicle, and converts the power given to each neutral point from the power receiving unit to charge the power storage device so as to charge the power storage device. And outputs a disconnect command to the relay when the power storage device is not charged from a power source outside the vehicle. The residual charge discharging method includes a determination step that determines whether or not the residual charge of the first capacitor can be discharged by the first discharge resistor when the power storage device is not charged from a power supply external to the vehicle, and discharge is impossible in the determination step. If it is determined, a first discharge step of outputting a connection command to the relay and discharging the residual charge by the discharge unit is included.

  Preferably, the residual charge discharging method further includes a second discharging step of discharging the residual charge of the power conversion circuit by the discharging unit. If it is determined in the determination step that discharge is impossible, the residual charge of the power conversion circuit is discharged in the second discharge step, and then the residual charge of the first capacitor is discharged in the first discharge step.

  Preferably, the power conversion circuit includes first and second inverters and a second capacitor. The first and second inverters are provided corresponding to the first and second AC motors, respectively. The second capacitor is connected between a pair of DC power lines connected to the first and second inverters. The discharge unit includes a second discharge resistor connected in parallel to the second capacitor.

  Preferably, the discharge unit includes an auxiliary device connected to the power conversion circuit. The first discharging step includes a sub-step for outputting a connection command to the relay and a sub-step for outputting an operation command to the auxiliary device.

  Preferably, the power conversion circuit includes first and second inverters and a second capacitor. The first and second inverters are provided corresponding to the first and second AC motors, respectively. The second capacitor is connected between a pair of DC power lines connected to the first and second inverters. The discharge unit is a first multiphase winding of the first AC motor and a second multiphase winding of the second AC motor. The first discharge step includes first to third sub-steps. In the first substep, a connection command is output to the relay. In the second sub-step, the first capacitor is switched from the first capacitor to the second capacitor through each neutral point, the first and second multiphase windings, and the first and second inverters in turn. After the residual charge moves, a disconnect command is output to the relay. In the third sub-step, at least one of the first and second inverters is controlled so that the accumulated charge of the second capacitor is discharged by at least one of the first and second multiphase windings.

  More preferably, the first to third sub-steps are sequentially repeated until the voltage between the power line pair falls below a specified value.

  According to the invention, the recording medium is a computer-readable recording medium, and records a program for causing the computer to execute any of the above-described discharge methods.

  In the present invention, a first capacitor is connected between the power line pair between the relay and the power receiving unit, and a first discharge resistor is connected in parallel to the first capacitor. Then, when the remaining charge of the first capacitor cannot be discharged by the first discharge resistor when the power storage device is not charged from the power supply outside the vehicle, a connection command is output to a relay that is normally turned off when not charged. As a result, the first capacitor is electrically connected to the power conversion circuit, and the residual charge of the first capacitor is supplied to the power conversion circuit.

  Therefore, according to the present invention, for example, even if the residual charge of the first capacitor cannot be discharged by the first discharge resistor due to the disconnection of the first discharge resistor, the discharge unit for discharging the residual charge of the power conversion circuit Can be used to discharge the residual charge of the first capacitor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a diagram showing a power train configuration of a hybrid vehicle shown as an example of an electric vehicle according to Embodiment 1 of the present invention. Referring to FIG. 1, hybrid vehicle 10 includes an engine 100, a first MG (Motor Generator) 110, a second MG 120, a power split mechanism 130, and drive wheels 140. Hybrid vehicle 10 includes power storage device 150, SMR (System Main Relay) 250, boost converter 200, first inverter 210, second inverter 220, first capacitor C1, and second capacitor C2. A first discharge resistor R1 and a voltage sensor 181 are further provided. Hybrid vehicle 10 further includes power input lines ACL 1 and ACL 2, DFR (Dead Front Relay) 260, LC filter 280, charging inlet 270, voltage sensor 182, current sensor 183, and ECU 170.

  Engine 100, first MG 110, and second MG 120 are coupled to power split device 130. This hybrid vehicle 10 travels by driving force from at least one of engine 100 and second MG 120. The power generated by the engine 100 is divided into two paths by the power split mechanism 130. That is, one is a path transmitted to the drive wheel 140 and the other is a path transmitted to the first MG 110.

  1st MG110 and 2nd MG120 are AC motors, for example, consist of a three-phase AC synchronous motor. Each of first MG 110 and second MG 120 includes a Y-connected three-phase coil as a stator coil. First MG 110 generates power using the power of engine 100 divided by power split device 130. For example, when the state of charge of power storage device 150 (hereinafter also referred to as “SOC (State Of Charge)”) becomes lower than a predetermined value, engine 100 is started and power is generated by first MG 110, and power storage device 150. Is charged.

  Second MG 120 generates driving force using at least one of the electric power stored in power storage device 150 and the electric power generated by first MG 110. Then, the driving force of second MG 120 is transmitted to driving wheel 140. Thus, second MG 120 assists engine 100 or causes the vehicle to travel with the driving force from second MG 120.

  When the vehicle is braked, second MG 120 is driven by drive wheel 140, and second MG 120 operates as a generator. Thereby, 2nd MG120 functions as a regenerative brake which converts driving energy into electric power and generates braking power. The electric power generated by second MG 120 is stored in power storage device 150.

  Power split device 130 includes a planetary gear including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear engages with the sun gear and the ring gear. The carrier supports the pinion gear so as to be capable of rotating, and is connected to the crankshaft of engine 100. The sun gear is connected to the rotation shaft of first MG 110. The ring gear is connected to the rotation shaft of second MG 120 and drive wheel 140.

  The power storage device 150 is a chargeable / dischargeable DC power source, and includes, for example, a secondary battery such as nickel metal hydride or lithium ion. The voltage of power storage device 150 is, for example, about 200V. In power storage device 150, in addition to the power generated by first MG 110 and second MG 120, power supplied from a power source outside the vehicle is stored as will be described later. A large-capacity capacitor can also be used as power storage device 150, and the power generated by first MG 110 and second MG 120 and the power from the power source outside the vehicle can be temporarily stored, and the stored power can be supplied to second MG 120. Any power buffer may be used.

  SMR 250 is provided between power storage device 150 and boost converter 200. SMR 250 is a relay for performing electrical connection / disconnection between power storage device 150 and a power conversion circuit including boost converter 200 and inverters 210 and 220, and is ON / OFF controlled by control signal SE from ECU 170. . That is, SMR 250 is turned on when the vehicle is running and when power storage device 150 is charged from a power source external to the vehicle, and power storage device 150 is electrically connected to the power conversion circuit. On the other hand, when the vehicle system is stopped, SMR 250 is turned off, and power storage device 150 is electrically disconnected from the power conversion circuit.

  First capacitor C1 is connected between positive electrode line PL1 and negative electrode line NL, and reduces a power fluctuation component contained in positive electrode line PL1 and negative electrode line NL. Boost converter 200 includes a reactor, and an upper arm and a lower arm connected in series between positive electrode line PL2 and negative electrode line NL. Each of the upper and lower arms includes an npn transistor and a diode connected in antiparallel to the npn transistor. The reactor is connected between positive line PL1 and the connection node of the upper and lower arms.

  For example, an IGBT (Insulated Gate Bipolar Transistor) can be used as the npn transistor. Further, a power switching element such as a power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) may be used instead of the npn transistor.

  Boost converter 200 boosts the power discharged from power storage device 150 to first MG 110 or second MG 120 based on control signal PWC from ECU 170 when power is supplied from power storage device 150 to first MG 110 or second MG 120. Supply. Boost converter 200 steps down the power supplied from first MG 110 or second MG 120 and outputs it to power storage device 150 based on control signal PWC when power storage device 150 is charged.

  When boost converter 200 receives shutdown signal SDC from ECU 170, boost converter 200 stops its operation. That is, when boost converter 200 receives shutdown signal SDC, boost converter 200 gates the npn transistors of the upper and lower arms.

  Second capacitor C2 is connected between positive electrode line PL2 and negative electrode line NL, and reduces power fluctuation components included in positive electrode line PL2 and negative electrode line NL. The first discharge resistor R1 is connected in parallel to the second capacitor C2, and can discharge the residual charge of the second capacitor C2. Voltage sensor 181 detects voltage VH between positive line PL2 and negative line NL, and outputs the detected value to ECU 170.

  First inverter 210 includes a U-phase arm, a V-phase arm, and a W-phase arm. U-phase arm, V-phase arm and W-phase arm are connected in parallel between positive electrode line PL2 and negative electrode line NL. Each phase arm includes two npn-type transistors connected in series, and a diode is connected in antiparallel to each npn-type transistor. The connection point of the two npn-type transistors in each phase arm is connected to the corresponding coil end in the first MG 110 and an end different from the neutral point 112.

  First inverter 210 converts AC power generated by first MG 110 into DC power based on control signal PWI <b> 1 from ECU 170, and supplies the DC power to boost converter 200. First inverter 210 converts DC power supplied from boost converter 200 into AC power and supplies it to first MG 110 based on control signal PWI1 when engine 100 is started.

  Second inverter 220 also has the same configuration as first inverter 210, and the connection point of the two npn transistors in each phase arm is a corresponding coil end in second MG 120 and an end different from neutral point 122. Connected to.

  Second inverter 220 converts DC power supplied from boost converter 200 into AC power based on control signal PWI2 from ECU 170, and supplies the AC power to second MG 120. In addition, the second inverter 220 converts the AC power generated by the second MG 120 into a DC current and supplies it to the boost converter 200 based on the control signal PWI2 during braking of the vehicle.

  Furthermore, when power storage device 150 is charged from a power supply external to the vehicle, first inverter 210 and second inverter 220 are applied to neutral point 112 of first MG 110 and neutral point 122 of second MG 120 from the power supply external to the vehicle. The AC power to be converted is converted into DC power based on control signals PWI 1 and PWI 2 from ECU 170, and the converted DC power is supplied to boost converter 200.

  Moreover, the 1st inverter 210 will stop the operation | movement, if the shutdown signal SD1 is received from ECU170. That is, when receiving the shutdown signal SD1, the first inverter 210 blocks the gates of the npn transistors forming the phase arms.

  Similarly, the second inverter 220 stops its operation when it receives the shutdown signal SD2 from the ECU 170. That is, when receiving the shutdown signal SD2, the second inverter 220 blocks the gates of the npn transistors forming the phase arms.

  The DFR 260 includes a power input line ACL1 disposed between the neutral point 112 of the first MG 110 and the charging inlet 270, and a power input line disposed between the neutral point 122 of the second MG 120 and the charging inlet 270. Provided in a power line pair consisting of ACL2. DFR 260 is a relay for electrically connecting / disconnecting charging inlet 270 and neutral points 112, 122, and is ON / OFF controlled by control signal DE from ECU 170. That is, when charging power storage device 150 from a power source outside the vehicle, DFR 260 is turned on, and charging inlet 270 is electrically connected to neutral points 112 and 122. On the other hand, when power storage device 150 is not charged from the power supply outside the vehicle, DFR 260 is turned off and charging inlet 270 is electrically disconnected from neutral points 112 and 122.

  The LC filter 280 includes a third capacitor C3, a second discharge resistor R2, a common mode choke coil 286, and a line bypass capacitor 288. Third capacitor C3 is connected between power input line ACL1 and power input line ACL2, and reduces normal mode noise included in power input lines ACL1 and ACL2 when power storage device 150 is charged from a power supply external to the vehicle. The second discharge resistor R2 is connected in parallel to the third capacitor C3 and can discharge the residual charge of the third capacitor C3. Common mode choke coil 286 and line bypass capacitor 288 reduce common mode noise included in power input lines ACL1 and ACL2 when power storage device 150 is charged from a power supply external to the vehicle.

  Charging inlet 270 is a power interface for receiving charging power from a power supply external to the vehicle. When charging power storage device 150 from a power source outside the vehicle, charging inlet 270 is connected to a connector of a charging cable for supplying power from the power source outside the vehicle to the vehicle.

  Voltage sensor 182 detects voltage VAC between power input line ACL1 and power input line ACL2, and outputs the detected value to ECU 170. Current sensor 183 detects current IAC flowing through power input line ACL1 when power storage device 150 is charged from a power supply external to the vehicle, and outputs the detected value to ECU 170. Note that the current sensor 183 may be provided in the power input line ACL2, and the current IAC flowing through the power input line ACL2 may be detected.

  ECU 170 generates control signals for driving SMR 250, boost converter 200, first inverter 210, second inverter 220, and DFR 260, and controls the operation of these devices. The configuration of ECU 170 will be described in detail later.

  FIG. 2 is a schematic configuration diagram of a portion related to the charging mechanism of hybrid vehicle 10 shown in FIG. Referring to FIG. 2, the charging cable connecting hybrid vehicle 10 and power supply 402 outside the vehicle includes a connector 310, a plug 320, a CCID (Charging Circuit Interrupt Device) relay 330, and a control pilot circuit 334. .

  Connector 310 is configured to be connectable to a charging inlet 270 provided in the vehicle. The connector 310 is provided with a limit switch 312. When connector 310 is connected to charging inlet 270, limit switch 312 is activated, and cable connection signal PISW indicating that connector 310 is connected to charging inlet 270 is input to ECU 170.

  Plug 320 is connected to a power outlet 400 provided in a house, for example. AC power is supplied to the power outlet 400 from a power source 402 (for example, a system power source).

  CCID relay 330 is provided on a power line for supplying charging power from power supply 402 to hybrid vehicle 10. The CCID relay 330 is on / off controlled by a control pilot circuit 334. When the CCID relay 330 is turned off, the electric circuit that supplies power from the power source 402 to the hybrid vehicle 10 is interrupted, and when the CCID relay 330 is turned on, power can be supplied from the power source 402 to the hybrid vehicle 10. Become.

  Control pilot circuit 334 outputs pilot signal CPLT to vehicle ECU 170 via connector 310 and charging inlet 270. The pilot signal CPLT notifies the rated current from the control pilot circuit 334 to the ECU 170 of the vehicle, and drives the CCID relay 330 from the ECU 170 to the control pilot circuit 334 based on the potential of the pilot signal CPLT operated by the ECU 170. It is a signal for instructing. Control pilot circuit 334 controls CCID relay 330 on / off based on a command from ECU 170 based on pilot signal CPLT.

  FIG. 3 is a functional block diagram of ECU 170 shown in FIGS. Referring to FIG. 3, ECU 170 includes a converter control unit 171, a first inverter control unit 172, a second inverter control unit 173, a charge control unit 174, and a discharge control unit 175.

  Converter control unit 171 generates control signal PWC for driving boost converter 200 based on the detected values of voltages VH and VL. Voltage VL is a voltage between positive line PL1 and negative line NL, and is detected by a voltage sensor (not shown). In addition, upon receiving a converter stop command from discharge control unit 175, converter control unit 171 outputs a shutdown signal SDC for stopping the operation of boost converter 200 to boost converter 200.

  First inverter control unit 172 controls to drive first MG 110 based on torque target value TR1 of first MG 110, each detected value of motor current MCRT1 and rotor rotation angle θ1 of first MG 110, and detected value of voltage VH. A signal PWI1 is generated. In addition, when the first inverter control unit 172 receives an inverter stop command from the discharge control unit 175, the first inverter control unit 172 outputs a shutdown signal SD1 for stopping the operation of the first inverter 210 to the first inverter 210.

  Second inverter control unit 173 controls to drive second MG 120 based on torque target value TR2 of second MG 120, each detected value of motor current MCRT2 and rotor rotation angle θ2 of second MG 120, and detected value of voltage VH. A signal PWI2 is generated. In addition, when the second inverter control unit 173 receives an inverter stop command from the discharge control unit 175, the second inverter control unit 173 outputs a shutdown signal SD2 for stopping the operation of the second inverter 220 to the second inverter 220.

  In the above, torque target values TR1 and TR2 are calculated based on the accelerator opening, the vehicle speed, and the like in another ECU (not shown). Motor currents MCRT1 and MCRT2 and rotor rotation angles θ1 and θ2 are detected by sensors (not shown).

  Further, first inverter control unit 172 and second inverter control unit 173 are configured so that first inverter 210 and second inverter 220 are each a single-phase PWM converter when charging power storage device 150 from power supply 402 outside the vehicle. Based on the zero-phase voltage command value from charge control unit 174, signals PWI1 and PWI2 are generated so as to operate as phase arms.

  Charging control unit 174 turns on SMR 250 and DFR 260 by activating control signals SE and DE when power storage device 150 is charged from power supply 402 outside the vehicle. Charging control unit 174 then converts first and second inverters 210 and 220 into single-phase PWM converters based on the detected values of voltage VAC and current IAC of AC power applied from power supply 402 to neutral points 112 and 122. A zero-phase voltage command value for operating as each phase arm is generated and output to the first inverter control unit 172 and the second inverter control unit 173. The zero-phase voltage command value is a command value for controlling a zero voltage vector (described later) of the first and second inverters 210 and 220.

  Discharge control unit 175 receives detected values of voltage VAC and voltage VH, cable connection signal PISW, and pilot signal CPLT. When the discharge control unit 175 receives a notification of the end of charging of the power storage device 150 from the power source 402 from the charge control unit 174, the discharge control unit 175 and the first capacitor C1, the second capacitor C2, and the power input line ACL1 A discharge process of the residual charge of each of the third capacitors C3 connected between the input line ACL2 is executed.

  FIG. 4 is a flowchart for explaining the control structure of the discharge process executed by discharge control unit 175 shown in FIG. The process shown in this flowchart is executed when the discharge control unit 175 receives a charge control end notification from the charge control unit 174 (FIG. 3).

  Referring to FIG. 4 together with FIGS. 1 to 3, discharge control unit 175 determines whether or not the input of charging power from power supply 402 is interrupted (step S <b> 10). Specifically, discharge controller 175 determines that connector 310 is not connected to charging inlet 270 based on cable connection signal PISW, or CCID relay 330 is turned off based on pilot signal CPLT. When the determination is made, it is determined that the input of charging power from the power source 402 is interrupted. If it is determined in step S10 that the input of charging power is not interrupted (NO in step S10), the process proceeds to step S120.

  If it is determined in step S10 that the input of charging power is interrupted (YES in step S10), discharge control unit 175 outputs a converter stop command to converter control unit 171 and first inverter control unit 172 and 2 An inverter stop command is output to the inverter control unit 173, and the boost converter 200, the first inverter 210, and the second inverter 220 are stopped (step S20).

  When boost converter 200, first inverter 210, and second inverter 220 are stopped, discharge control unit 175 turns off SMR 250 and DFR 260 by deactivating control signals SE and DE (step S30). And the discharge control part 175 performs the discharge process of the 1st capacitor | condenser C1 and the 2nd capacitor | condenser C2 (step S40). Specifically, the discharge control unit 175 supplies the first inverter 210 and the second inverter 220 to the first inverter control unit 172 and the second inverter control unit 173 so that only the d-axis current flows to the first MG 110 and the second MG 120, respectively. A command is output, and the first inverter control unit 172 and the second inverter control unit 173 control the first inverter 210 and the second inverter 220, respectively, based on the command. As a result, the residual charges of the first capacitor C1 and the second capacitor C2 are consumed by the first MG 110 and the second MG 120 without generating torque in the first MG 110 and the second MG 120. Although boost converter 200 is stopped, the residual charge of first capacitor C1 is supplied to first inverter 210 and second inverter 220 through the diode of the upper arm of boost converter 200, and first MG 110 and second MG 120. Is consumed by.

  Next, the discharge control unit 175 determines whether or not the state in which the absolute value of the voltage VAC is equal to or greater than a specified threshold value continues (step S50). This determination process determines whether or not the residual charge of the third capacitor C3 connected between the power input line ACL1 and the power input line ACL2 is discharged by the second discharge resistor R2. When it is determined in step S50 that the absolute value of voltage VAC is smaller than the threshold value (NO in step S50), discharge control unit 175 causes residual charge in third capacitor C3 to be discharged by second discharge resistor R2. After confirming that the first capacitor C1 and the second capacitor C2 have been discharged (not shown), the process proceeds to step S120.

  On the other hand, when it is determined in step S50 that the state where the absolute value of voltage VAC is equal to or greater than the threshold value continues (YES in step S50), discharge control unit 175 causes residual charge in third capacitor C3 to be 2 It is determined that the discharge cannot be performed by the discharge resistor R2. For example, when the second discharge resistor R2 is disconnected, the state where the absolute value of the voltage VAC is equal to or greater than the threshold value continues.

  Then, when the discharge processing of first capacitor C1 and second capacitor C2 is completed (YES in step S60), discharge control unit 175 activates control signal DE to turn on DFR 260 (step S70). The voltages VL and VH become substantially zero, and the first inverter 210 and the second inverter 220 are stopped, thereby confirming the end of the discharge processing of the first capacitor C1 and the second capacitor C2.

  When DFR 260 is turned on, first and second capacitors C1 and C2 are discharged, so that positive line PL2 is output from third capacitor C3 via DFR 260, first MG 110 and second MG 120, and first inverter 210 and second inverter 220. The residual charge of the third capacitor C3 flows to the negative electrode line NL. Accordingly, the residual charge of the third capacitor C3 is discharged by the first discharge resistor R1 connected between the positive electrode line PL2 and the negative electrode line NL.

  Then, the discharge control unit 175 determines whether or not the absolute value of the voltage VAC is lower than a specified threshold value (step S80), and determines that the absolute value of the voltage VAC is lower than the threshold value (step S80). If YES in S80, it is determined that the discharge of the third capacitor C3 has been completed, and the DFR 260 is turned off (step S90).

  Finally, the discharge controller 175 determines whether or not the detected value of the voltage VH is greater than or equal to a specified threshold value (step S100). If it is determined that voltage VH is lower than the threshold value (NO in step S100), the process proceeds to step S120, and a series of processes ends. On the other hand, when it is determined in step S100 that voltage VH is equal to or higher than the threshold value (YES in step S100), discharge control unit 175 executes the discharge process of second capacitor C2 by the same process as in step S40 ( Step S110).

  FIG. 5 is a timing chart showing the voltages VAC and VH at the end of charging and the operation of main devices. Referring to FIG. 5, at time t1, power reception ends, and first inverter 210, second inverter 220, and boost converter 200 are stopped. Thereafter, when the DFR 260 is turned off and the CCID relay 330 is turned off at time t2, the power supply from the power source 402 is stopped.

  At this time, if the second discharge resistor R2 is normal, the residual charge of the third capacitor C3 is discharged by the second discharge resistor R2, and the voltage VAC converges to zero (dotted line). However, when the residual charge of the third capacitor C3 cannot be discharged by the second discharge resistor R2, such as when the second discharge resistor R2 is disconnected, the voltage VAC maintains the value at the time t2 (solid line).

  On the other hand, when CCID relay 330 is turned off at time t2, SMR 250 is turned off at time t3. Then, at time t4, the first inverter 210 and the second inverter 220 operate, and the first capacitor C1 and the second capacitor C2 are discharged using the first MG 110 and the second MG 120. Thereafter, when voltage VH converges to near zero at time t5, first inverter 210 and second inverter 220 are stopped.

  When the discharge of the first capacitor C1 and the second capacitor C2 is completed, the DFR 260 is turned on at time t6. Then, the residual charge of third capacitor C3 flows from third capacitor C3 to positive line PL2 and negative line NL via DFR 260, first MG110 and second MG120, and first inverter 210 and second inverter 220, and the first discharge resistance The residual charge is discharged by R1. When voltage VAC converges to near zero at time t7, DFR 260 is turned off and a series of discharge processing ends.

Next, a method for charging power storage device 150 from power supply 402 outside the vehicle will be described.
FIG. 6 is a diagram showing a zero-phase equivalent circuit of first and second inverters 210 and 220 and first and second MGs 110 and 120 shown in FIG. Each of first inverter 210 and second inverter 220 includes a three-phase bridge circuit, and there are eight patterns of ON / OFF combinations of six switching elements in each inverter. Two of the eight switching patterns have zero interphase voltage, and such a voltage state is called a zero voltage vector. For the zero voltage vector, the three switching elements of the upper arm can be regarded as the same switching state (all on or off), and the three switching elements of the lower arm can also be regarded as the same switching state.

  Zero voltage vectors of first inverter 210 and second inverter 220 based on zero phase voltage command values generated based on detected values of voltage VAC and current IAC when power storage device 150 is charged from power supply 402 outside the vehicle. Is controlled. Therefore, in FIG. 6, the three switching elements of the upper arm of the first inverter 210 are collectively shown as an upper arm 210A, and the three switching elements of the lower arm of the first inverter 210 are collectively shown as a lower arm 210B. ing. Similarly, the three switching elements of the upper arm of the second inverter 220 are collectively shown as an upper arm 220A, and the three switching elements of the lower arm of the second inverter 220 are collectively shown as a lower arm 220B.

  As shown in FIG. 6, this zero-phase equivalent circuit includes a single-phase PWM converter that receives a single-phase AC power supplied from the power source 402 to the neutral point 112 of the first MG 110 and the neutral point 122 of the second MG 120. Can be seen. Therefore, the first inverter 210 and the second inverter 220 change the zero voltage vector based on the zero phase voltage command value, and the switching control is performed so that the first inverter 210 and the second inverter 220 operate as an arm of the single phase PWM converter. By doing so, AC power supplied from the power source 402 can be converted to DC power and supplied to the positive electrode line PL2 and the negative electrode line NL. Then, power storage device 150 can be charged via boost converter 200.

  As described above, in the first embodiment, after the charging of power storage device 150 from power supply 402 outside the vehicle, when the remaining charge of third capacitor C3 cannot be discharged by second discharge resistor R2, it is turned off at the end of charging. The DFR 260 is turned on. Thereby, the residual charge of the third capacitor C3 flows from the third capacitor C3 to the positive electrode line PL2 and the negative electrode line NL via the DFR 260, the first MG 110 and the second MG 120, and the first inverter 210 and the second inverter 220. Therefore, according to the first embodiment, even if the residual charge of the third capacitor C3 cannot be discharged by the second discharge resistor R2 due to the disconnection of the second discharge resistor R2, it is connected between the positive electrode line PL2 and the negative electrode line NL. Further, the residual charge of the third capacitor C3 can be discharged using the first discharge resistor R1.

[Embodiment 2]
FIG. 7 is a diagram showing a power train configuration of a hybrid vehicle shown as an example of an electric vehicle according to the second embodiment. Referring to FIG. 7, this hybrid vehicle 10A further includes a DC-DC converter 292 and an auxiliary power storage device 294 in the configuration of hybrid vehicle 10 according to the first embodiment shown in FIG. Instead, an ECU 170A is provided.

  DC-DC converter 292 is connected to positive electrode line PL1 and negative electrode line NL. DC-DC converter 292 operates based on control signal CNTL from ECU 170A, and reduces the power supplied from positive electrode line PL1 and negative electrode line NL to the voltage level of auxiliary power storage device 294, and thus the auxiliary power storage device. To 294.

  Auxiliary power storage device 294 is a power source for auxiliary equipment that can be charged and discharged, and is composed of, for example, a secondary battery such as nickel metal hydride, lithium ion, or lead. The auxiliary power storage device 294 stores the electric power supplied from the DC-DC converter 292, and supplies the stored electric power to the auxiliary machine according to the request of each auxiliary machine (not shown).

  ECU 170A generates control signals for driving SMR 250, boost converter 200, first inverter 210, second inverter 220, DFR 260 and DC-DC converter 292, and controls the operation of these devices.

  FIG. 8 is a functional block diagram of ECU 170A shown in FIG. Referring to FIG. 8, ECU 170A includes a discharge control unit 175A instead of discharge control unit 175 in the configuration of ECU 170 in the first embodiment shown in FIG.

  When the discharge control unit 175A determines that the remaining charge of the third capacitor C3 cannot be discharged by the second discharge resistor R2 after the charging of the power storage device 150 from the power source 402 is completed, the DC- Further, the DC converter 292 is further used to execute a discharge process for discharging the residual charge of the third capacitor C3.

  That is, in the second embodiment, when the residual charge of the third capacitor C3 cannot be discharged by the second discharge resistor R2, the DC-DC converter 292 is further used together with the first discharge resistor R1, and the third capacitor C3 is more promptly used. Is to be discharged.

  FIG. 9 is a flowchart for explaining the control structure of the discharge process executed by discharge control unit 175A shown in FIG. The process shown in this flowchart is also executed when discharge control unit 175A receives a charge control end notification from charge control unit 174 (FIG. 8).

  Referring to FIG. 9, this flowchart further includes steps S72, S74, and S82 in the flowchart shown in FIG. That is, when DFR 260 is turned on in step S70, discharge control unit 175A outputs a command to converter control unit 171 to turn on upper arm 202 (FIG. 7) of boost converter 200, and upper arm of boost converter 200 202 is turned on (step S72). As a result, positive electrode line PL2 and positive electrode line PL1 become conductive, and charge can flow from positive electrode line PL2 to positive electrode line PL1.

  Next, the discharge control unit 175A outputs a control signal CNTL for driving the DC-DC converter 292 to the DC-DC converter 292, and drives the DC-DC converter 292 (step S74). As a result, the residual charge of the third capacitor C3 flowing from the third capacitor C3 to the positive electrode line PL2 and the negative electrode line NL is output to the auxiliary power storage device 294 by the DC-DC converter 292.

  If it is determined in step S80 that the absolute value of voltage VAC has become lower than the prescribed threshold value (YES in step S80), discharge control unit 175A stops DC-DC converter 292 and performs converter control. A converter stop command is output to unit 171 to stop boost converter 200 (step S82). Then, the process proceeds to step S90, and the DFR 260 is turned off. The processing in other steps is as described in FIG.

  FIG. 10 is a timing chart showing voltages VAC and VH at the end of charging and operations of main devices in the second embodiment. Referring to FIG. 10, up to time t5 is the same as the timing chart in the first embodiment shown in FIG.

  When the discharge of the first capacitor C1 and the second capacitor C2 is completed at time t5, the DFR 260 is turned on at time t6. Further, upper arm 202 of boost converter 200 is turned on, and DC-DC converter 292 operates. Then, the residual charge of third capacitor C3 flows from third capacitor C3 to positive line PL1 and negative line NL via DFR 260, first MG 110 and second MG 120, first inverter 210 and second inverter 220, and boost converter 200, The residual charge is discharged by the DC-DC converter 292.

  In the second embodiment, since the residual charge is discharged by the DC-DC converter 292 together with the first discharge resistor R1, the remaining is performed more quickly than in the first embodiment in which the discharge is performed only by the first discharge resistor R1. The charge is discharged and the voltage VAC quickly converges to zero.

  When voltage VAC converges to near zero at time t7, DC-DC converter 292 is stopped and upper arm 202 of boost converter 200 is turned off. At time t8, DFR 260 is turned off, and a series of discharge processing ends.

  As described above, according to the second embodiment, when the residual charge of the third capacitor C3 cannot be discharged by the second discharge resistor R2, the residual charge is discharged using the DC-DC converter 292 together with the first discharge resistor R1. Thus, the residual charge of the third capacitor C3 can be discharged quickly.

[Embodiment 3]
When the residual charge of the third capacitor C3 cannot be discharged by the second discharge resistor R2, in the first embodiment, the residual charge is discharged using the first discharge resistor R1, and in the second embodiment, the DC-DC converter 292 is further discharged. Was used to discharge. In the third embodiment, a configuration in which the residual charge of the third capacitor C3 is discharged using the first MG 110 and the second MG 120 is shown.

  1 to 3 again, hybrid vehicle 10B according to the third embodiment includes ECU 170B in place of ECU 170 in the configuration of hybrid vehicle 10 according to the first embodiment. ECU 170B includes a discharge control unit 175B in place of discharge control unit 175 in the configuration of ECU 170.

  FIG. 11 is a flowchart for illustrating a control structure of discharge processing executed by discharge control unit 175B in the third embodiment. The process shown in this flowchart is also executed when the discharge control unit 175B receives a charge control end notification from the charge control unit 174 (FIG. 3).

  Referring to FIG. 11, this flowchart includes step S84 instead of step S80 in the flowchart shown in FIG. 4, and includes steps S130 and S140 instead of steps S100 and S110. That is, when DFR 260 is turned on in step S70, discharge control unit 175B determines whether or not the absolute value of the deviation between voltage VAC and voltage VH is smaller than specified value δ (step S84). This specified value δ determines that the residual charge of the third capacitor C3 flows from the third capacitor C3 to the second capacitor C2 when the DFR 260 is turned on, and the voltage VAC and the voltage VH are substantially at the same level. It is a value for.

  If it is determined in step S84 that the absolute value of the deviation is smaller than the prescribed value δ (YES in step S84), the process proceeds to step S90, and DFR 260 is turned off. Thereafter, the discharge control unit 175B performs the discharge process of the second capacitor C2 using the first inverter 210 and the second inverter 220 by the same process as in step S40 (step S130).

  When the discharge process of the second capacitor C2 is completed, the discharge control unit 175B determines whether or not the absolute value of the voltage VAC is smaller than a specified threshold value (step S140). Note that the threshold value used in step S50 may be used as this threshold value. When it is determined that the absolute value of voltage VAC is smaller than the threshold value (YES in step S140), discharge control unit 175B proceeds to the process in step S120.

  On the other hand, when it is determined in step S140 that the absolute value of voltage VAC is equal to or greater than the threshold value (NO in step S140), discharge control unit 175B proceeds to step S70 again. Thereby, a series of processes shown in steps S70, S84, S90, and S130 are executed again. Then, a series of processes shown in steps S70, S84, S90, and S130 are repeatedly executed until it is determined in step S140 that the absolute value of voltage VAC is smaller than the threshold value.

  As described above, according to the third embodiment, when the residual charge of the third capacitor C3 cannot be discharged by the second discharge resistor R2, the residual charge is transferred to the second capacitor C2, and the first MG 110 and the second MG 120 are used. Since the discharge is positively performed, the residual charge of the third capacitor C3 can be discharged quickly.

  In the third embodiment, the second embodiment may be further combined, and the DC-DC converter 292 may be further used to discharge the residual charge of the third capacitor C3.

  In each of the above embodiments, the control in discharge control units 175, 175A, 175B is actually performed by a CPU (Central Processing Unit), and the CPU is shown in the flowcharts shown in FIGS. A program including each step is read from a ROM (Read Only Memory), the read program is executed, and processing is executed according to the flowcharts shown in FIGS. Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program including the steps of the flowcharts shown in FIGS.

  In each of the above-described embodiments, the series / parallel type hybrid vehicle has been described in which the power splitting mechanism 130 divides the power of the engine 100 and can be transmitted to the drive wheels 140 and the first MG 110. It can also be applied to other types of hybrid vehicles. That is, for example, a so-called series-type hybrid vehicle that uses the engine 100 only to drive the first MG 110 and generates the driving force of the vehicle only by the second MG 120, or only regenerative energy among the kinetic energy generated by the engine 100 The present invention can also be applied to a hybrid vehicle that is recovered as electric energy, a motor-assist type hybrid vehicle in which a motor assists the engine as the main power if necessary.

  The present invention is also applicable to a hybrid vehicle that does not include boost converter 200.

  The present invention can also be applied to an electric vehicle that does not include engine 100 and travels only by electric power, and a fuel cell vehicle that further includes a fuel cell as a power source in addition to a power storage device.

  In the above, first MG 110 and second MG 120 correspond to “first AC motor” and “second AC motor” in the present invention, respectively, and charging inlet 270 corresponds to “power receiving unit” in the present invention. . Power input lines ACL1 and ACL2 correspond to “power line pairs” in the present invention, and DFR 260 corresponds to “relay” in the present invention. Further, the third capacitor C3 corresponds to the “first capacitor” in the present invention, and the second discharge resistor R2 corresponds to the “first discharge resistor” in the present invention.

  Further, ECUs 170, 170A, and 170B correspond to "control device" in the present invention, and second capacitor C2 corresponds to "second capacitor" in the present invention. Furthermore, the first discharge resistor R1 corresponds to the “second discharge resistor” in the present invention, and the DC-DC converter 292 corresponds to the “auxiliary device” in the present invention. Furthermore, the three-phase coil of the first MG 110 corresponds to the “first multi-phase winding” in the present invention, and the three-phase coil of the second MG 120 corresponds to the “second multi-phase winding” in the present invention. To do.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

1 is a diagram showing a power train configuration of a hybrid vehicle shown as an example of an electric vehicle according to Embodiment 1 of the present invention. FIG. It is a schematic block diagram of the part regarding the charging mechanism of the hybrid vehicle shown in FIG. It is a functional block diagram of ECU shown in FIGS. It is a flowchart for demonstrating the control structure of the discharge process performed by the discharge control part shown in FIG. It is the timing chart which showed the voltage at the time of charge completion, and operation | movement of main apparatuses. It is the figure which showed the zero-phase equivalent circuit of the 1st and 2nd inverter and 1st and 2nd MG which are shown in FIG. FIG. 6 is a diagram showing a power train configuration of a hybrid vehicle shown as an example of an electric vehicle according to a second embodiment. It is a functional block diagram of ECU shown in FIG. It is a flowchart for demonstrating the control structure of the discharge process performed by the discharge control part shown in FIG. 6 is a timing chart showing the voltage at the end of charging and the operation of main devices in the second embodiment. 10 is a flowchart for illustrating a control structure of a discharge process executed by a discharge control unit in the third embodiment.

Explanation of symbols

  10, 10A, 10B Hybrid vehicle, 100 Engine, 110 1st MG, 112, 122 Neutral point, 120 2nd MG, 130 Power split mechanism, 140 Drive wheel, 150 Power storage device, 170, 170A, 170B ECU, 171 Converter control unit 172, first inverter control unit, 173 second inverter control unit, 174 charge control unit, 175, 175A, 175B discharge control unit, 181, 182 voltage sensor, 183 current sensor, 200 boost converter, 210 first inverter, 202, 210A, 220A Upper arm, 210B, 220B Lower arm, 220 Second inverter, 250 SMR, 260 DFR, 270 Charging inlet, 280 LC filter, 286 Common mode choke coil, 288 Line bypass capacitor Sensor, 292 DC-DC converter, 294 Auxiliary power storage device, 310 connector, 312 limit switch, 320 plug, 330 CCID relay, 334 control pilot circuit, 400 power outlet, 402 power supply, C1 first capacitor, C2 second capacitor , C3 third capacitor, R1 first discharge resistor, R2 second discharge resistor, PL1, PL2 positive line, NL negative line, ACL1, ACL2 power input line.

Claims (13)

An electric vehicle capable of charging a power storage device capable of storing electric power for vehicle travel from a power source outside the vehicle,
First and second AC motors each including a star-connected first multiphase winding and a star-connected second multiphase winding as stator windings;
A power conversion circuit provided between the power storage device and the first and second AC motors;
A discharge unit configured to be able to discharge residual charges of the power conversion circuit;
A power receiving unit configured to receive power supplied from the power source;
A pair of power lines disposed between the power reception unit and the neutral point of the first multiphase winding and between the power reception unit and the neutral point of the second multiphase winding;
Provided in the power line pair, electrically connecting the power receiving unit to the neutral points when charging the power storage device from the power source, and A relay that electrically disconnects from the neutral point;
A first capacitor connected between the power line pair between the relay and the power receiving unit;
A first discharge resistor connected in parallel to the first capacitor between the relay and the power receiving unit;
At the time of charging, a connection command is output to the relay, and the power conversion circuit is controlled so as to charge the power storage device by converting the power given from the power reception unit to the neutral points, and the non-charging And a controller for outputting a disconnection command to the relay,
The control device outputs a connection command to the relay so as to discharge the residual charge by the discharge unit when the residual charge of the first capacitor cannot be discharged by the first discharge resistor during the non-charging. Electric vehicle.   The said control apparatus outputs the said connection command to the said relay, after the residual charge of the said power conversion circuit is discharged by the said discharge part when the discharge of the residual charge of the said 1st capacitor | condenser is impossible. Electric vehicle. The power conversion circuit includes:
First and second inverters provided corresponding to the first and second AC motors, respectively;
A second capacitor connected between a pair of DC power lines connected to the first and second inverters,
The electric vehicle according to claim 1, wherein the discharge unit includes a second discharge resistor connected in parallel to the second capacitor. The discharge unit includes an auxiliary device connected to the power conversion circuit,
3. The electric motor according to claim 1, wherein the control device outputs the connection command to the relay and an operation command to the auxiliary device when the residual charge of the first capacitor cannot be discharged. vehicle. The power conversion circuit includes:
First and second inverters provided corresponding to the first and second AC motors, respectively;
A second capacitor connected between a pair of DC power lines connected to the first and second inverters,
The discharge unit is the first multiphase winding of the first AC motor and the second multiphase winding of the second AC motor;
The controller outputs the connection command to the relay when the residual charge of the first capacitor cannot be discharged, and outputs the neutral points, the first and second multiphase windings, and the first And after the residual charge of the first capacitor moves from the first capacitor to the second capacitor via the second inverter and the second inverter in sequence, the disconnection command is output to the relay, and the first and second 3. The electric vehicle according to claim 1, wherein at least one of the first and second inverters is controlled such that at least one of the two multiphase windings discharges the accumulated charge of the second capacitor. .   The control device outputs the connection command to the relay until the voltage between the power line pair falls below a specified value, and the relay after the residual charge has moved from the first capacitor to the second capacitor. The electric vehicle according to claim 5, wherein the output of the disconnect command to and the control of at least one of the first and second inverters are sequentially repeated. A method for discharging a residual charge in an electric vehicle capable of charging a power storage device capable of storing electric power for vehicle travel from a power source outside the vehicle,
The electric vehicle is
First and second AC motors each including a star-connected first multiphase winding and a star-connected second multiphase winding as stator windings;
A power conversion circuit provided between the power storage device and the first and second AC motors;
A discharge unit configured to be able to discharge residual charges of the power conversion circuit;
A power receiving unit configured to receive power supplied from the power source;
A pair of power lines disposed between the power reception unit and the neutral point of the first multiphase winding and between the power reception unit and the neutral point of the second multiphase winding;
Provided in the power line pair, electrically connecting the power receiving unit to the neutral points when the power storage device is charged from the power source, and connecting the power receiving unit to the neutral points when the power storage device is not charged from the power source. A relay that electrically disconnects from the neutral point;
A first capacitor connected between the power line pair between the relay and the power receiving unit;
A first discharge resistor connected in parallel to the first capacitor between the relay and the power receiving unit;
At the time of charging, a connection command is output to the relay, and the power conversion circuit is controlled so as to charge the power storage device by converting the power given from the power reception unit to the neutral points, and the non-charging And a controller for outputting a disconnection command to the relay,
The discharge method is:
A determination step of determining whether or not the first discharge resistor can discharge the residual charge of the first capacitor during the non-charging;
And a first discharging step of outputting the connection command to the relay and discharging the residual charge by the discharging unit when it is determined in the determining step that discharging is impossible. A second discharging step of discharging residual charges of the power conversion circuit by the discharging unit;
If it is determined in the determination step that discharge is impossible, the residual charge of the power conversion circuit is discharged in the second discharge step, and then the residual charge of the first capacitor is discharged in the first discharge step. The residual charge discharging method according to claim 7. The power conversion circuit includes:
First and second inverters provided corresponding to the first and second AC motors, respectively;
A second capacitor connected between a pair of DC power lines connected to the first and second inverters,
9. The residual charge discharging method according to claim 7, wherein the discharge unit includes a second discharge resistor connected in parallel to the second capacitor. 10. The discharge unit includes an auxiliary device connected to the power conversion circuit,
The first discharging step includes
A sub-step of outputting the connection command to the relay;
The residual charge discharging method according to claim 7, further comprising a sub-step of outputting an operation command to the auxiliary device. The power conversion circuit includes:
First and second inverters provided corresponding to the first and second AC motors, respectively;
A second capacitor connected between a pair of DC power lines connected to the first and second inverters,
The discharge unit is the first multiphase winding of the first AC motor and the second multiphase winding of the second AC motor;
The first discharging step includes
A first sub-step for outputting the connection command to the relay;
Residue of the first capacitor from the first capacitor to the second capacitor through the neutral points, the first and second multiphase windings, and the first and second inverters in sequence. A second sub-step of outputting the disconnect command to the relay after the charge has moved;
And a third sub-step for controlling at least one of the first and second inverters to discharge the accumulated charge of the second capacitor by at least one of the first and second multiphase windings. The discharge method of the residual charge of Claim 7 or Claim 8.   12. The residual charge discharging method according to claim 11, wherein the first to third sub-steps are sequentially repeated until a voltage between the power line pair falls below a specified value.   A computer-readable recording medium having recorded thereon a program for causing a computer to execute the residual charge discharging method according to any one of claims 7 to 12.

Images