JP2008182842A - Electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a short circuit current certainly during tracked run of an electric vehicle upon occurrence of short circuit fault in the semiconductor power switching element constituting an inverter. <P>SOLUTION: Upon occurrence of short circuit fault in the switching element of an inverter, an ECU 10 performs short circuit protection control for generating interruption commands ME1 and ME2 of contactors MC1 and MC2. A switch element 250 generates an on signal SON in response to the attachment of a traction hook, and a power supply relay 320 forms a power supply passage from a power supply node 270 to the ECU 10 in response to generation of the on signal ON. Consequently, short circuit protection control can be performed by operating the ECU 10 automatically even if an ignition switch is turned off when the traction hook is attached. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric vehicle capable of traveling with a driving force generated by an AC motor generator (motor generator), and more particularly to a technique for preventing damage caused by back electromotive force of an AC motor generator.

  In recent years, electric vehicles such as hybrid vehicles and electric vehicles have attracted a great deal of attention as environmentally friendly vehicles. Such an electric vehicle includes a power supply device including a secondary battery and the like, and a motor generator capable of generating driving force by receiving electric power from the power supply device. The motor generator generates a driving force when starting or accelerating, and converts the kinetic energy of the vehicle into electric energy and recovers it to the power supply device during braking or the like. Thus, in order to control the motor generator according to the traveling state of the vehicle, a general electric vehicle has a power conversion device that can convert power between DC power and AC power, such as an inverter device. Installed.

  The electrical energy recovery operation as described above is realized by using the back electromotive force generated by the motor generator. That is, when the power converter is appropriately controlled, a current flows from the motor generator to the power supply device, and is recovered as power energy.

  On the other hand, if a situation occurs in which the motor generator rotates for some reason before the power converter becomes controllable, the power converter, the power supply device, and the power The surrounding area can be damaged. Therefore, conventionally, techniques for preventing damage due to back electromotive force have been proposed.

  For example, in Japanese Patent Application Laid-Open No. 2006-87175 (Patent Document 1), when a failure occurs in a motor drive circuit (inverter), a travel motor (motor generator), or the like, the vehicle is pulled or downhill by gravity. A vehicle control device for preventing a member from being damaged by a counter electromotive force of a motor is disclosed. The vehicle control device is configured to warn the driver (for example, a notification that prohibits towing the vehicle) when detecting a short circuit failure of the electric motor.

Japanese Patent Laying-Open No. 2005-348583 (Patent Document 2) controls a main relay incorporated between a drive motor (motor generator) that drives drive wheels and a drive battery that supplies current to the drive motor. A configuration of a control device for an electric vehicle is disclosed. According to this control device, when the main relay is switched to the disconnected state, the main relay is switched to the disconnected state when it is determined that the output current from the driving battery is lower than the predetermined current and the vehicle speed is lower than the predetermined vehicle speed. It is done. As a result, it is possible to prevent welding failure of the main relay and protect the inverter and the high-voltage auxiliary machine from the induced voltage of the drive motor.
JP 2006-87175 A JP-A-2005-348583

  When the switching element that constitutes the power converter is short-circuited, etc., power conversion by the power converter cannot be performed, and the motor generator cannot be driven, so it is pulled by another vehicle and carried to a repair shop or the like. (Hereinafter, such a traveling state is referred to as “towed traveling”).

  In an electric vehicle equipped with a permanent magnet type motor as a motor generator for driving a vehicle, a short circuit formed by a switching element, a reverse parallel diode of another phase, and a coil winding of the motor generator during towed traveling A short circuit current is generated in the loop due to the back electromotive force of the motor generator. This short-circuit current tends to be excessive because it is concentrated in a specific phase and may cause further equipment damage.

  However, in the control apparatus for an electric vehicle disclosed in Patent Document 1, the drive motor and the inverter (drive circuit) cannot be electrically disconnected even if the main relay is disconnected. It is impossible to prevent a short circuit current during towing.

  In addition, since the driver is not always on board during towed traveling, it is possible to reliably prevent the occurrence of a short-circuit current only by issuing a warning to the driver as in the vehicle control device disclosed in Patent Document 2. Can not do it. In particular, even when a mechanism for preventing a short-circuit current is installed, unless power is supplied to a control device (typically, an electronic control unit: ECU) that controls the mechanism during towed traveling, There is a possibility that the short-circuit path cannot be prevented.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a short-circuit current during towed travel when a short-circuit fault occurs in a power semiconductor switching element constituting an inverter device. It is an object of the present invention to provide an electric vehicle capable of reliably preventing the occurrence of the above.

  The electric vehicle according to the present invention includes an AC motor generator, an inverter device, a switch, and a short-circuit protection means. The AC motor generator includes a rotor on which a magnet is mounted, and is configured to be able to transmit rotational force to and from wheels. The inverter device includes a plurality of power semiconductor switching elements and is configured to convert a DC voltage of a power source into a driving voltage of an AC motor generator. The switch is interposed in series with a power line connecting the inverter device and the AC motor generator. The short-circuit protection means is provided with a device (typically a tow hook) that is attached when the vehicle is towed when a short-circuit failure is detected in at least some of the plurality of power semiconductor switching elements. In response to this, the switch is configured to open.

  According to the electric vehicle, when a short-circuit failure has occurred in at least a part of the power semiconductor switching element that constitutes the inverter device, an appliance (typically a tow hook) that is worn during towed traveling. In response to the mounting of the inverter, the inverter device and the AC motor generator can be electrically disconnected by a switch. Therefore, even if the back electromotive force is generated by rotating the rotor of the AC motor generator due to the towed travel, no short circuit current flows through the AC motor generator and the inverter device, so that further equipment damage is surely generated. Can be prevented.

  Preferably, the short-circuit protection means includes a control device configured to open the switch when a short-circuit fault is detected in at least a part of the plurality of power semiconductor switching elements, and the appliance is attached. Power supply means for automatically operating the control device in response. In particular, the power supply means is configured to supply power to the control device in response to the installation of the instrument even when the ignition switch is off. Alternatively, the power supply means includes a switch element that is mechanically operated by a mounted instrument, and a power supply relay that is configured to form a power supply path to the control device when the switch element is operated.

  By adopting such a configuration, the control device for controlling the switch can be automatically operated in response to the mounting of the tow traveling device (the tow hook). It becomes possible to reliably execute the short-circuit current prevention control by opening.

  According to the electric vehicle of the present invention, it is possible to reliably prevent the occurrence of a short-circuit current during towing travel when a short-circuit fault occurs in the power semiconductor switching element constituting the inverter device.

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

  Referring to FIG. 1, vehicle 100 according to the first embodiment of the present invention is, as an example, an electric vehicle configured to be able to travel by driving force generated by a motor generator. The “electric vehicle” is a concept including a vehicle configured to generate driving force from an electric motor (motor) and rotate driving wheels by electric power supplied from a power supply device. Including hybrid vehicles, electric vehicles and fuel cell vehicles. In the following description, it is assumed that electric vehicle 100 is a hybrid vehicle. That is, the electric vehicle 100 can be driven by a driving force generated by an engine (not shown) and can be generated by a driving force from the engine.

  Electric vehicle 100 includes a power supply device PS, a capacitor C2, an inverter device INV, a motor generator MG, a drive shaft 8, a differential gear 6, drive wheels 4, and contactors MC1 and MC2.

  The power supply device PS is configured to be able to supply DC power to the inverter device INV via the main positive line PL and the main negative line NL. More specifically, power supply device PS includes a power storage device BAT, system relays SR1 and SR2, a capacitor C1, and a converter unit CONV.

  The power storage device BAT is configured to be able to be charged / discharged by DC power. As an example, the power storage device BAT includes a secondary battery such as a lithium ion battery or a nickel metal hydride battery, or a power storage element such as an electric double layer capacitor.

  System relay SR1 is interposed between the positive electrode of power storage device BAT and positive line ML, and electrically connects or disconnects the positive electrode of power storage device BAT and positive line ML in accordance with system command SE. Similarly, system relay SR2 is interposed between the negative electrode of power storage device BAT and main negative line NL, and electrically connects the negative electrode of power storage device BAT and main negative line NL in accordance with system command SE or Cut off.

  Capacitor C1 is connected between positive line ML and main negative line NL, and smoothes the charge / discharge voltage of power storage device BAT.

  Converter unit CONV is configured to boost DC power discharged from power storage device BAT and supply it to inverter device INV, and to step down DC power regenerated from inverter device INV and supply it to power storage device BAT. Is also configured. Specifically, converter unit CONV includes a chopper circuit including power semiconductor switching elements (hereinafter referred to as “switching elements”) Q1 and Q2, diodes D1 and D2, and inductor L1. In converter unit CONV, switching operations of switching elements Q1 and Q2 are performed in accordance with switching command PWC.

  Switching elements Q1 and Q2 are connected in series between main positive line PL and main negative line NL. In addition, one end of the inductor L1 is connected to a connection point between the switching element Q1 and the switching element Q2. In the present embodiment, the switching element is composed of an IGBT, but alternatively, a bipolar switching element, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a GTO (Gate Turn Off thyristor) may be used.

  The diode D1 is connected between the emitter and collector of the switching element Q1 so that a feedback current can flow from the emitter side to the collector side of the switching element Q1. Similarly, the diode D2 is connected between the emitter and collector of the switching element Q2 so that a feedback current can flow from the emitter side to the collector side of the switching element Q2.

  The inductor L1 is interposed between the connection point between the switching element Q1 and the switching element Q2 and the positive line ML, and accumulates and releases electromagnetic energy by current generated according to the switching operation of the switching elements Q1 and Q2. Repeat. That is, the converter unit CONV realizes a step-up operation or a step-down operation by repeatedly storing and releasing electromagnetic energy in the inductor L1.

  Capacitor C2 is connected between main positive line PL and main negative line NL, and smoothes DC power transferred between power supply device PS and inverter device INV. That is, the capacitor C2 functions as a power buffer.

  Inverter device INV performs power conversion between power supply device PS and motor generator MG. That is, the inverter device INV converts the DC power supplied from the power supply device PS through the main positive line PL and the main negative line NL into three phase voltages (U phase voltage, V phase voltage, W phase voltage). While being able to convert into phase alternating current power, the three phase alternating current power supplied from motor generator MG can also be converted into direct current power. Specifically, inverter device INV includes a U-phase arm circuit 11, a V-phase arm circuit 12, and a W-phase arm circuit 13. Inverter device INV and motor generator MG are electrically connected by a U-phase supply line LN1, a V-phase supply line LN2, and a W-phase supply line LN3 corresponding to the “power line” in the present invention.

  U-phase arm circuit 11 includes switching elements Q11 and Q12 connected in series between main positive line PL and main negative line NL, and diodes D11 and D12 connected in antiparallel to switching elements Q11 and Q12, respectively. . In U-phase arm circuit 11, switching operations of switching elements Q11 and Q12 are performed in accordance with switching command PWM, whereby a U-phase voltage is generated at connection point N1. The U-phase voltage is supplied to motor generator MG via U-phase supply line LN1.

  Diode D11 is connected between the emitter and collector of switching element Q11 so that a feedback current can flow from the emitter side to the collector side of switching element Q11. Similarly, diode D12 is connected between the emitter and collector of switching element Q12 so that a feedback current can flow from the emitter side to the collector side of switching element Q12. That is, diodes D11 and D12 are connected in reverse parallel so as to allow a current flow from main negative line NL to main positive line PL and to block a current flow from main positive line PL to main negative line NL. The

  Such diodes D11 and D12 serve to suppress a surge that occurs immediately after the switching elements Q11 and Q12 transition from the on state to the off state, respectively. Therefore, during normal switching operation, current does not flow into the diodes D11 and D12 from the main positive line PL or the main negative line NL.

  Similarly, V-phase arm circuit 12 includes switching elements Q21 and Q22 connected in series between main positive line PL and main negative line NL, and diodes D21 and D22 connected in antiparallel to switching elements Q21 and Q22, respectively. Including. Then, V-phase arm circuit 12 generates a V-phase voltage at connection point N2, and supplies it to motor generator MG via V-phase supply line LN2.

  Similarly, W-phase arm circuit 13 includes switching elements Q31 and Q32 connected in series between main positive line PL and main negative line NL, and diodes D31 and D31 connected in reverse parallel to switching elements Q31 and Q32, respectively. D32. W-phase arm circuit 13 generates a W-phase voltage at connection point N3 and supplies it to motor generator MG through W-phase supply line LN3.

  The motor generator MG generates a driving force in accordance with the three-phase AC power supplied from the inverter device INV, and rotationally drives the driving wheels 4 via the driving shaft 8 and the differential gear 6 that are mechanically connected.

  Motor generator MG is formed of, for example, a three-phase AC rotating electric machine including a rotor in which permanent magnets are embedded. That is, as shown in FIG. 2, the rotor 90 of the motor generator MG is configured by embedding a permanent magnet 95 in a mounting hole provided in a rotor core 94 formed of laminated steel plates. When the rotor 90 in which the permanent magnet 95 is embedded rotates, a temporal and positional magnetic flux change occurs in the motor generator MG, and a counter electromotive force proportional to the rotational speed of the rotor 90 is generated. A stator (not shown) of motor generator MG is wound with three-phase coil windings of U, V, and W phases, each of which is connected to each of connection points N1 to N3. The other ends of the lines are connected to each other at a neutral point.

  When the driving wheel 4 can be rotationally driven by an engine (not shown), a power split mechanism using a planetary gear mechanism or the like is inserted on the driving force transmission path from the motor generator MG, and the motor generator MG. The driving force generated by the engine may be appropriately distributed.

  Contactor MC1 is interposed in series with U-phase supply line LN1, and electrically shuts off U-phase arm circuit 11 and motor generator MG in response to control command ME1. Similarly, contactor MC2 is interposed in series with W-phase supply line LN3, and electrically shuts off W-phase arm circuit 13 and motor generator MG in response to control command ME2. On the other hand, during normal times when control commands ME1 and ME2 are not generated, contactors MC1 and MC2 are maintained in a conductive state, and electrically connect U-phase arm circuit 11, W-phase arm circuit 13 and motor generator MG.

  As will be described later, contactors MC1 and MC2 are controlled so as to cut off a short-circuit current generated by a counter electromotive voltage of motor generator MG when any of the switching elements constituting inverter device INV is short-circuited. That is, the contactors MC1 and MC2 correspond to the “switch” in the present invention.

  Current sensors 7 are arranged in association with U-phase supply line LN1, V-phase supply line LN2, and W-phase supply line LN3, respectively. The three current sensors 7 detect the current values (Iu, Iv, Iw) of the phase currents flowing through the U-phase supply line LN1, the V-phase supply line LN2, and the W-phase supply line LN3, respectively. It outputs to ECU (electronic control unit) 10 which is a “control device”.

  The ECU 10 is configured to start operation by being supplied with power in response to an on signal (IGON) of an ignition switch corresponding to an activation command that is turned on at the start of vehicle operation. During operation, the ECU 10 executes a program stored in advance so that a signal transmitted from each sensor (not shown), a traveling state, a change rate of the accelerator opening, a charging state of the power storage device, a stored map, and the like are stored. An arithmetic process is executed based on this. Thereby, ECU10 produces | generates system command SE, switching command PWC, PWM, etc. according to a driver | operator's operation so that the electric vehicle 100 may be in a desired driving | running state.

  When a failure occurs in each switching element, a failure detection signal FSG including information indicating the failure content (identification of short circuit failure, open failure, etc.) is generated and applied to the ECU 10. When ECU 10 receives failure detection signal FSG, ECU 10 determines that it is in a state in which normal traveling is impossible, issues a warning to the driver, and shuts off system relays SR1 and SR2 by system command SE. Furthermore, information indicating the identification of the failed switching element and the content of the failure is stored in a nonvolatile manner as a diag code.

  Next, with reference to FIG. 3, the short-circuit current generated by the counter electromotive voltage of the motor generator MG when the switching element is short-circuited will be described.

  FIG. 3A shows a short-circuit current that is generated when a short-circuit fault occurs in the switching element Q22 of the V-phase arm circuit 12. FIG. FIG. 3B shows a state where the short-circuit current is cut off by opening the contactors MC1 and MC2.

  Referring to FIG. 3 (a), if a short circuit failure occurs in switching element Q22 of U-phase arm circuit 13, U-phase arm circuit 11, motor generator MG, and V-phase arm are generated by the counter electromotive force. A short-circuit current Is1 flows through a current path including the circuit 12. At the same time, short-circuit current Is2 flows through a current path including W-phase arm circuit 13, motor generator MG, and V-phase arm circuit 12.

  Here, focusing on the direction of the short-circuit current flowing through each supply line, the short-circuit current flowing through the U-phase supply line LN1 and the W-phase supply line LN3 is directed from the inverter device INV to the motor generator MG. The short-circuit current flowing through phase supply line LN1 is the direction from motor generator MG to inverter device INV. Therefore, as shown in FIG. 3B, by opening contactors MC1 and MC2, any short-circuit current flowing from inverter device INV in the direction of motor generator MG is cut off. Further, when a short circuit failure occurs in the switching element Q21 of the V-phase arm circuit 12, the short circuit current is cut off by the same operation.

  When a short circuit failure occurs in switching element Q11 or Q12 of U-phase arm circuit 11, the short-circuit current can be interrupted by opening at least contactor MC1, and switching element Q31 or When a short-circuit failure occurs in Q32, the short-circuit current can be interrupted by opening at least the contactor MC2. However, from the viewpoint of simplifying the control configuration, when a short-circuit fault has occurred in any of the switching elements of the inverter device INV, the short-circuit current is reliably generated by shutting off the contactors MC1 and MC2. Can be prevented.

  However, in order to perform such contactor cutoff control for preventing a short-circuit current, ECU 10 that generates control commands ME1 and ME2 needs to be operating. For this reason, if the towed traveling is executed in a state where the ignition switch is not turned on (IGON signal is off), the contactor cutoff control cannot be executed. May occur.

  Therefore, in the electric vehicle according to the present embodiment, by providing the short-circuit protection configuration described below, a configuration capable of reliably performing contactor cutoff control during non-traction traveling is realized.

FIG. 4 is a schematic diagram illustrating a tow hook that is attached during towed traveling.
Referring to FIG. 4, when electrically powered vehicle 100 is towed to be pulled by another vehicle, traction hook 200 is mounted in mounting hole 210 provided in the body in advance. The tow hook 200 includes an insertion portion 202 that is inserted into the mounting hole 210 and a connecting portion 204 that is connected to another vehicle by a wire or the like. The insertion portion 202 is attached to the attachment hole 210 by screwing of a screw mechanism or the like. That is, the tow hook 200 is shown as a representative example of an instrument that is attached to the electric vehicle 100 during towed traveling.

FIG. 5 is a schematic diagram for explaining the structure of the attachment portion of the tow hook 200.
Referring to FIG. 5, switch element 250 has a movable part 230 that is mechanically operated when traction hook 200 is attached to mounting hole 210, and an on signal SON that is generated when movable part 230 is activated. Signal generation circuit 240. As a result, the switch element 250 is mechanically operated by the attached pulling hook 200 and outputs an ON signal SON.

  FIG. 6 is a schematic block diagram illustrating a short circuit protection configuration in the electric vehicle according to the embodiment of the present invention.

Referring to FIG. 6, short circuit protection unit 300 includes an ECU 10 and a power supply control unit 310.
Power supply control unit 310 includes switch element 250 shown in FIG. 5, logic gate (OR gate) 260, and power supply relay 320.

  Switch element 250 is always connected to power supply node 270 and receives supply of power supply voltage Vb. The power supply voltage Vb may be supplied by stepping down the output voltage of the power storage device BAT as the travel power source shown in FIG. 1 by a DC / DC converter (not shown). You may supply with another DC power supply (for example, battery for auxiliary machines).

  The logic gate 260 receives the ON signal SON from the switch element 250 and the ON signal IGON of the ignition switch as inputs, and turns on the output signal when at least one of them is turned on.

  Power supply relay 320 is connected between power supply node 270 and ECU 10, and is turned on when the output signal of logic gate 260 is on, and is turned off otherwise. Therefore, the power supply control unit 310 supplies the power supply voltage Vb to the ECU 10 by the power supply relay 320 when at least one of the ON signal IGON of the ignition switch and the ON signal SON indicating the attachment of the tow hook 200 is turned on. be able to. That is, power supply relay 320 forms a power supply path to ECU 10 when ON signal SON is generated. Thus, the power supply control unit 310 is configured to automatically operate the ECU 10 by supplying power to the ECU 10 in response to the attachment of the tow hook 200 even when the ignition switch is off. ing.

FIG. 7 is a flowchart for explaining the operation of the ECU at the start of power feeding.
Referring to FIG. 7, the ECU does not execute the following steps S110 to S130 until power feeding is started (step S100). When power feeding is started (when YES is determined in step S100), the ECU 10 reads the diagnosis code stored so far in step S110 as part of a normal ECU activation sequence. The ECU 10 first checks the diagnosis code at the start of power feeding to determine whether or not normal vehicle travel is possible.

  The ECU 10 determines whether a short circuit fault has occurred in any of the power semiconductor switching elements (inverter elements) constituting the inverter device INV based on the read diagnostic code (step S120). When YES is determined in step S120, ECU 10 generates control commands ME1 and ME2 for shutting off contactors MC1 and MC2 in step S130.

  In response to this, as shown in FIG. 6, the contactors MC1 and MC2 are opened. As a result, as shown in FIG. 3B, no short-circuit current is generated even when the counter electromotive force of the motor generator MG is generated by towing.

  Referring to FIG. 7 again, when NO is determined in step S120, ECU 10 ends the subroutine shown in FIG. 7 without executing step S130. The ECU 10 continues to execute another normal activation sequence.

  Further, the ECU 10 performs the same processing as that in steps S120 and S130 even when a diagnostic code indicating that a short-circuit fault has occurred in any of the inverter elements during the operation is performed, and the contactor performs MC1 and MC2 off commands ME1 and ME2 are generated. That is, if the ECU 10 is in operation (that is, during power feeding) and stores a diagnosis code indicating that a short-circuit failure has occurred in any of the inverter elements, the ECU 10 automatically issues the OFF commands ME1 and ME2. Is configured to occur.

  As described above, in the electric vehicle according to the present embodiment, the ECU 10 automatically supplies power to the ECU 10 in response to the attachment of a device (typically a tow hook) that is to be worn during towed traveling. Then, the cutoff control of the contactors MC1 and MC2 can be executed. As a result, when a short-circuit failure has occurred in at least a part of the power semiconductor switching elements constituting the inverter device, the contactors MC1 and MC2 are surely cut off when the electric vehicle 100 is towed, and the motor generator Since the short-circuit current caused by the counter electromotive force generated in can be reliably interrupted, the occurrence of further equipment damage can be surely prevented.

  In addition, in response to the attachment of a tow hook or the like, a configuration that directly controls the contactors MC1 and MC2 or a configuration that forcibly generates an ON signal IGON of the ignition switch can prevent short-circuit current as described above. It can also be realized. However, as in this embodiment, the control configuration can be prevented from becoming complicated by using a configuration in which the normal activation sequence of the ECU 10 is used to issue a disconnection command for the contactors MC1 and MC2. Further, by supplying power limitedly to a control device (ECU) necessary for the control for shutting off the contactors MC1 and MC2, generation of unnecessary power consumption can be prevented as compared with the case where the IGON signal is forcibly turned on.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram of an electric vehicle according to an embodiment of the present invention. It is a figure explaining the rotor structure of the motor generator shown in FIG. It is a circuit diagram explaining a short circuit current generated by a counter electromotive voltage of the motor generator MG at the time of a short circuit failure of a switching element. It is the schematic explaining the hook for towing with which it is equipped at the time of towed running. It is the schematic explaining the structure of the attachment part of the hook for tow | pulling. It is a schematic block diagram explaining the short circuit protection structure in the electric vehicle of embodiment of this invention. It is a flowchart explaining the operation | movement at the time of the electric power feeding start of ECU.

Explanation of symbols

  4 drive wheels, 6 differential gears, 7 current sensors, 8 drive shafts, 11 U-phase arm circuits, 12 V-phase arm circuits, 13 W-phase arm circuits, 90 rotors, 94 rotor cores, 95 permanent magnets, 100 electric vehicles, 200 traction Hook, 202 insertion section, 204 connection section, 210 mounting hole, 230 movable section, 240 signal generation circuit, 250 switch element, 260 logic gate, 270 power supply node, 300 short circuit protection section, 310 power supply control section, 320 power supply relay, BAT power storage device (running power supply), C1, C2 capacitor, CONV converter, D1, D2, D11, D12, D21, D22, D31, D32 diode, FSG failure detection signal, IGON on signal (ignition switch), INV inverter Device, Is1, Is Short-circuit current, L1 inductor, LN1 U-phase supply line, LN2 V-phase supply line, LN3 W-phase supply line, MC1, MC2 contactor, ME1, ME2 control command (contactor), MG motor generator, ML positive line, NL main negative line , PL main positive line, PS power supply device, PWC switching command (converter), PWM switching command (inverter), Q1, Q2, Q11, Q12, Q21, Q22, Q31, Q32 switching element, SE system command, SON on signal ( SR1, SR2 system relay, Vb power supply voltage.

Claims (5)

An AC motor generator configured to have a rotor mounted with a magnet and to be able to transmit rotational force to and from the wheels;
An inverter device having a plurality of power semiconductor switching elements configured to convert a DC voltage of a power source into a driving voltage of the AC motor generator;
A switch interposed in series with a power line connecting between the inverter device and the AC motor generator;
When the short circuit failure is detected in at least a part of the plurality of power semiconductor switching elements, the switch is opened in response to attachment of a device to be mounted when the vehicle is towed. An electric vehicle comprising: a configured short circuit protection means. The short-circuit protection means includes
A control device configured to open the switch when a short-circuit fault is detected in at least some of the plurality of power semiconductor switching elements; and
The electric vehicle according to claim 1, further comprising a power supply means for automatically operating the control device in response to the attachment of the appliance.   The electric vehicle according to claim 2, wherein the power supply means is configured to supply power to the control device in response to the attachment of the appliance even when the ignition switch is off. The power supply means is
A switch element that is mechanically actuated by the mounted instrument;
The electric vehicle according to claim 2, further comprising: a power supply relay configured to form a power supply path to the control device when the switch element is operated.   The electric vehicle according to claim 1, wherein the instrument is a tow hook.

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