JP5699969B2 - Converter fault detection device and converter fault detection method - Google Patents

Description

  The present invention relates to a converter failure detection device and a converter failure detection method for detecting a failure of a converter mounted on a vehicle.

  2. Description of the Related Art A vehicle that travels by a driving force of a motor, such as an electric vehicle, a hybrid vehicle, and a fuel cell vehicle, is known. Such a vehicle includes a converter that converts a voltage from a battery by turning on / off a switching element, and an inverter that converts the voltage from the converter into an AC voltage and supplies the AC voltage to a motor.

  In the converter, a short circuit failure of the switching element may occur, and as a result, the element may be burned out or the load may be broken. Conventionally, the voltage VL from the battery is actually boosted by the converter according to the command value, the voltage VH output from the converter after the boost is measured, and the actually measured voltage VH is compared with the voltage value indicated by the command value. By doing so, the short circuit fault of the switching element of the converter was detected. In this case, when the measured voltage VH and the voltage value indicated by the command value are different, it is determined that a short circuit failure has occurred in the switching element.

  Patent Document 1 below is a power supply device including a charger provided with an abnormality detection relay, and the battery is connected to an external power source by detecting the voltage by turning on the abnormality detection relay. Thus, a power supply device that detects a short circuit on the external power supply side of the charger is disclosed.

  In Patent Document 2 below, a first battery and a first booster circuit are connected by a first system main relay, and a second battery and a second booster are connected by a second system main relay. An apparatus for detecting a failure of a switching element of a second booster circuit based on a voltage on a second battery side of the second booster circuit when the connection with the circuit is released is disclosed.

  In Patent Document 3 below, a time change component of the terminal voltage of the switching element in the chopper circuit is calculated, and a section in which failure detection is interrupted based on the timing at which the switching element is turned on / off and the time change component is provided. A device that detects and detects a failure of a switching element except for the section to be interrupted is disclosed.

JP 2010-213552 A JP 2010-259265 A JP 2011-193549 A

  As described above, according to the method of operating the converter to function as a booster circuit and comparing the boosted voltage VH with the voltage value indicated by the command value, it is possible to detect a short circuit failure of the switching element. When a short-circuit failure occurs, the actual pressure is not boosted, so the necessary torque cannot be obtained due to insufficient power, resulting in torque loss and engine run-up, resulting in reduced drivability. There is a risk. Further, when a failure is detected by boosting in a situation where boosting is not required, fuel consumption is reduced.

  In addition, the device described in Patent Document 1 only detects a short circuit on the side of the external power supply with respect to the charger, and is not a device that detects a failure of the switching element of the converter. In addition, the device described in Patent Document 2 described above is configured when the first battery and the first booster circuit are connected and the connection between the second battery and the second booster circuit is released. However, it is only possible to detect a failure of the switching element, and simply waiting for such a situation limits the chance of failure detection and may miss the timing of failure detection. In addition, the device described in Patent Document 3 cannot detect a failure of the switching element in a section where the failure detection is interrupted, and in this case, the failure detection timing may be missed.

  An object of the present invention is to provide a converter failure detection apparatus and a converter failure detection method capable of positively creating a situation for detecting a converter failure and detecting a converter failure.

  The present invention is provided between an inverter connected to a motor mounted on a vehicle and a first battery, and is connected in series between a positive bus on the inverter and a negative bus on the inverter. Including an arm-side switching element and a lower arm-side switching element, and by turning on / off the lower arm-side switching element, the voltage from the first battery is boosted and supplied to the inverter, and the upper arm-side switching is performed. A converter failure detection device for detecting a failure of a converter for stepping down a voltage from the inverter and supplying the first battery by turning on / off an element, wherein the failure is detected between the first battery and the converter. A DC / DC converter connected to the first battery, wherein the voltage is lower than that of the first battery and is supplied to an auxiliary device mounted on the vehicle. A DC / DC converter that steps down the voltage from the first battery and supplies the second battery to the second battery that turns on the upper arm side switching element and the lower arm when the vehicle is stopped. By turning off the side switching element, the voltage VL on the first battery side of the converter and the voltage VH on the inverter side of the converter are made the same, and then the upper arm side switching element and the lower arm side switching With the element turned off, the connection between the first battery and the converter and the connection between the first battery and the DC / DC converter are released with the converter and the DC / DC converter connected. Thereafter, the DC / DC converter is operated, and the voltage VH on the inverter side of the converter is A converter failure detecting apparatus characterized by and a control means for detecting a failure of the converter are.

  Further, the control means operates the DC / DC converter, and then based on the magnitude relationship between the voltage VL on the first battery side of the converter and the voltage VH on the inverter side of the converter. It is preferable to detect a failure.

  Further, the present invention is provided between an inverter connected to a motor mounted on a vehicle and a first battery, and is connected in series between a positive bus on the inverter and a negative bus on the inverter. An upper arm side switching element and a lower arm side switching element, and the voltage from the first battery is boosted by turning on / off the lower arm side switching element, and is supplied to the inverter. A converter failure detection method for detecting a failure of a converter for stepping down a voltage from the inverter and supplying the first battery by turning on / off a side switching element, wherein the vehicle is stopped , By turning on the upper arm side switching element and turning off the lower arm side switching element, the converter of the converter A first step of making the voltage VL on one battery side equal to a voltage VH on the inverter side of the converter; and after the first step, the upper arm side switching element and the lower arm side switching element, A second step of turning off the first battery and the converter, and a DC / DC connected between the first battery and the converter after the second step. A DC / DC converter that lowers the voltage from the first battery and supplies it to a second battery that is lower in voltage than the first battery and supplies a voltage to an auxiliary device mounted on the vehicle. A third step of operating the DC converter in a state in which the connection with the first battery is released; and after the third step, on the inverter side of the converter A fourth step of detecting a failure of the converter on the basis of the pressure VH, a converter fault detection method characterized by including the.

  Further, in the fourth step, after the DC / DC converter is operated, the magnitude of the voltage VL on the first battery side of the converter and the voltage VH on the inverter side of the converter is based on the magnitude relationship. Preferably, converter failure is detected.

  According to the present invention, it is possible to detect a converter failure by creating a situation for detecting a converter failure while the vehicle is stopped without actually boosting the converter.

It is a figure which shows schematic structure of the vehicle carrying the converter failure detection apparatus which concerns on embodiment of this invention. It is a flowchart which shows an example of the operation | movement by the converter failure detection apparatus which concerns on embodiment of this invention. It is a graph which shows the time change of the voltage by the side of the direct-current power supply of a converter, and the voltage by the side of an inverter.

  A converter failure detection apparatus according to an embodiment of the present invention will be described with reference to FIG. The converter failure detection apparatus according to this embodiment is mounted on an electric vehicle, a hybrid vehicle, or a fuel cell vehicle that includes a motor as a drive source. FIG. 1 shows a schematic configuration of a hybrid vehicle as an example.

  As an example, the vehicle shown in FIG. 1 includes a DC power supply 10, system relays SMRB and SMRG, a converter 11, inverters 12 and 13, voltage sensors 14 and 15, an auxiliary battery 20, and a DC / DC converter 30. And a control device 40, motor generators MG1 and MG2, and an engine (internal combustion engine) (not shown). An inverter 12 is connected to motor generator MG 1, an inverter 13 is connected to motor generator MG 2, and converter 11 is provided between DC power supply 10 and inverters 12 and 13.

  An engine (not shown) generates driving force using combustion energy of fuel such as gasoline as a source. The driving force generated by the engine is divided into two paths. One is a path that transmits to the drive shaft that drives the wheels via a reduction gear (not shown), and the other is a path that transmits to the motor generator MG1.

  Motor generators MG 1 and MG 2 are, for example, three-phase AC synchronous motors, and are driven by electric power stored in DC power supply 10. Motor generator MG1 functions as a generator driven by an engine (not shown), and is a motor that can operate as an electric motor for the engine to start the engine. Motor generator MG2 is a motor for generating torque for driving the drive wheels of the vehicle.

The inverter 12 is configured by combining a plurality of switching elements and diodes, and based on a switching control signal S _INV from the control device 40, the inverter 12 generates a DC voltage (voltage VH) supplied from the DC power supply 10 side via the converter 11. It is converted into a three-phase AC voltage and supplied to motor generator MG1. Thereby, motor generator MG1 is driven to generate the required torque specified by the torque command value. Inverter 12 also converts the AC voltage generated by motor generator MG1 into a DC voltage based on switching control signal S _INV from control device 40 during regenerative braking, and converts the converted DC voltage to a DC power source via converter 11. 10 is supplied. Regenerative braking refers to braking that involves regenerative power generation when the driver operating the hybrid vehicle performs a foot brake operation, or the foot brake is not operated. It also includes decelerating the vehicle.

The inverter 13 is configured by combining a plurality of switching elements and diodes. Based on the switching control signal S _INV from the control device 40, the inverter 13 generates a DC voltage (voltage VH) supplied from the DC power supply 10 via the converter 11. It is converted into a three-phase AC voltage and supplied to the motor generator MG2. Thereby, motor generator MG2 is driven to generate the required torque specified by the torque command value. In addition, inverter 13 converts the AC voltage generated by motor generator MG2 into a DC voltage based on switching control signal S _INV from control device 40 during regenerative braking, and converts the converted DC voltage to DC power supply via converter 11. 10 is supplied.

  The DC power supply 10 is a DC power source that can be charged and discharged, for example. As the DC power source 10, for example, a lithium ion assembled battery, a nickel hydride assembled battery, or a capacitor having a terminal voltage of several hundred volts can be used. The DC power supply 10 corresponds to an example of a “first battery”.

  Here, regarding the power supply lines of the DC power supply 10 and the inverters 12 and 13, if the high voltage side is referred to as a positive side bus and the low voltage side is referred to as a negative side bus, the line connected to the plus terminal of the DC power supply 10 is The positive bus on the DC power supply 10 side, and the line connected to the negative terminal of the DC power supply 10 is the negative bus on the DC power supply 10 side. Similarly, the high voltage power line of the inverters 12 and 13 is a positive bus on the inverters 12 and 13 side, and the low voltage power line is a negative bus on the inverters 12 and 13 side. As shown in FIG. 1, the negative bus on the DC power supply 10 side and the negative bus on the inverters 12 and 13 side are connected to each other to form a common negative bus.

  System relays SMRB and SMRG are provided between DC power supply 10 and converter 11. System relays SMRB and SMRG conduct or cut off the power supply path from DC power supply 10 to converter 11 and inverters 12 and 13. Specifically, system relay SMRB is connected between the positive terminal of DC power supply 10 and the positive side bus. System relay SMRG is connected between the negative terminal of DC power supply 10 and the negative side bus. System relays SMRB and SMRG are turned on or off in accordance with signal SE from control device 40, respectively.

  Between system relays SMRB, SMRG and converter 11, capacitor C1 is provided between the positive side bus and the negative side bus. The capacitor C1 is a capacitive element that smoothes the voltage (voltage VL) supplied from the DC power supply 10 to the converter 11 and holds the voltage VL. Similarly, a capacitor C <b> 2 is provided between the positive electrode side bus and the negative electrode side bus between the converter 11 and the inverters 12 and 13. The capacitor C2 is a capacitive element that smoothes the voltage (voltage VH) supplied from the converter 11 and holds the voltage VH.

The converter 11 performs voltage conversion between the voltage VL on the DC power supply 10 side and the voltage VH on the inverters 12 and 13 side based on the switching control signal S _CNV from the control device 40. Converter 11 is constituted by a step-up / step-down chopper circuit as an example, and is reversely connected in parallel to reactor L, two switching elements Q1 and Q2 connected in series with each other, and two switching elements Q1 and Q2. The diodes D1 and D2 are included.

The reactor L is an element having an inductance value L. When the current I flows, the reactor L can accumulate (LI ² ) / 2 electromagnetic energy and can release the accumulated electromagnetic energy. One side terminal of reactor L is connected to one side terminal of DC power supply 10, and the other side terminal of reactor L is connected to a connection point where two switching elements Q1, Q2 are connected in series with each other.

  The two switching elements Q1 and Q2 have a function of allowing the reactor L to store or release electromagnetic energy, thereby exchanging power while performing voltage conversion between the DC power supply 10 side and the inverters 12 and 13 side. Have. The switching element Q1 on one side of the two switching elements Q1, Q2 is provided between the other terminal of the reactor L and the positive side bus of the inverters 12, 13, and the other switching element Q2 is the other side of the reactor L. Provided between the side terminal and the negative side bus of inverters 12 and 13.

  When the two switching elements Q1 and Q2 are distinguished, an element connected to the positive bus on the inverters 12 and 13 is referred to as an upper arm switching element, and an element connected to the common negative bus on the lower arm switching element. It can be called. In the example shown in FIG. 1, the switching element Q1 corresponds to the upper arm side switching element, and the switching element Q2 corresponds to the lower arm side switching element. As the switching elements Q1, Q2, for example, an IGBT (Insulated Gate Bipolar Transistor) is used.

  When the converter 11 functions as a booster circuit, the lower arm side switching element Q2 is turned on / off in a state where the upper arm side switching element Q1 is turned off. That is, when the lower arm side switching element Q2 is on, a current flowing from the DC power source 10 forms a loop that returns to the DC power source 10 via the reactor L and the lower arm side switching element Q2. Magnetic energy is stored in the reactor L while current flows through the loop. When the switching element Q2 on the lower arm side is turned off, a current flowing from the DC power supply 10 flows to the inverters 12 and 13 via the reactor L and the diode D1, and forms a loop returning to the DC power supply 10. During this time, in addition to the electric energy from the DC power supply 10, the magnetic energy accumulated in the reactor L is supplied to the inverters 12 and 13, so that the voltage supplied to the inverters 12 and 13 is boosted.

  On the other hand, when the converter 11 functions as a step-down circuit, the upper arm side switching element Q2 is turned on / off in a state where the lower arm side switching element Q2 is turned off. That is, when the switching element Q1 on the upper arm side is on, the current regenerated from the inverters 12 and 13 flows to the switching element Q1, the reactor L, and the DC power source 10 on the upper arm side, and the inverters 12 and 13 Form a loop back to the side. Thus, when the switching element Q1 on the upper arm side is in the ON state, the voltage VL on the DC power supply 10 side of the converter 11 and the voltage VH on the inverters 12 and 13 side of the converter 11 are the same. Further, when the switching element Q1 on the upper arm side is in an OFF state, a loop composed of the reactor L, the DC power supply 10, and the diode D2 is formed, and the magnetic energy accumulated in the reactor L is regenerated in the DC power supply 10.

  The voltage sensor 14 detects the voltage VL across the capacitor C1 and outputs the value of the voltage VL to the control device 40. The voltage sensor 15 detects the voltage VH across the capacitor C2 and outputs the value of the voltage VH to the control device 40.

  In addition, a current sensor (not shown) that detects current in at least two phases is provided on the wiring connecting each phase arm of inverter 12 and each phase coil of motor generator MG1. Similarly, the wiring connecting each phase arm of inverter 13 and each phase coil of motor generator MG2 is provided with a current sensor (not shown) that detects current in at least two phases. The current value detected by the current sensor is output to the control device 40.

  Each of motor generators MG1 and MG2 is provided with a position sensor (not shown) such as a resolver for detecting the rotation angle of each rotor of motor generators MG1 and MG2. Data indicating the rotation angle detected by the position sensor is output to the control device 40.

  As the auxiliary battery 20, a chargeable / dischargeable battery having a voltage lower than that of the DC power supply 10 is used. For example, a chargeable / dischargeable battery of 12 V or the like is used. An auxiliary machine (not shown) is connected to the auxiliary battery 20. This auxiliary machine includes, for example, an air conditioner, an interior lamp, a car navigation system and the like mounted on the vehicle. Auxiliary battery 20 can be charged by receiving power from DC power supply 10 via DC / DC converter 30. The auxiliary battery 20 corresponds to an example of a “second battery”.

  DC / DC converter 30 is connected between positive and negative buses between system relays SMRB and SMRG and converter 11. The DC / DC converter 30 includes a plurality of switching elements that operate under the control of the control device 40. The DC / DC converter 30 steps down the voltage supplied from the DC power supply 10 to a predetermined DC voltage and supplies it to the auxiliary battery 20 or the auxiliary machine.

Control device 40 controls the operation of each part in accordance with the driving situation, thereby switching the traveling mode by motor generators MG1, MG2 between motor traveling, charging traveling, engine / motor traveling, and the like. For example, the control device 40 outputs the switching control signal S _CNV to the converter 11 to control the switching operation of the switching elements Q1 and Q2, thereby causing the converter 11 to function as a step-up circuit or a step-down circuit. When driving the motor generator MG1, the control device 40 generates the switching control signal S _INV based on the voltage VH, the torque command value, the current value of the motor generator MG1, and the like, and sends the switching control signal S _INV to the inverter 12. The switching operation of the inverter 12 is controlled by outputting. Similarly, when driving motor generator MG2, control device 40 generates switching control signal S _INV based on voltage VH, torque command value, current value of motor generator MG2, and the like, and uses switching control signal S _INV as inverter 13. To control the switching operation of the inverter 13. Control device 40 also generates a signal SE for turning on / off system relays SMRB, SMRG and outputs the signal SE to system relays SMRB, SMRG.

  The converter failure detection device that detects a failure of converter 11 includes DC / DC converter 30 and control device 40, and detects a short-circuit failure of switching element Q 1 on the upper arm side of converter 11.

  Next, the operation of the converter failure detection apparatus according to the present embodiment will be described with reference to FIGS. FIG. 2 is a flowchart showing an example of the operation of the converter failure detection apparatus according to this embodiment. FIG. 3 is a graph showing temporal changes in the voltage VL on the DC power supply 10 side of the converter 11 and the voltage VH on the inverters 12 and 13 side. Of the two graphs shown in FIG. 3, the upper graph shows the time change of the voltage VH, and the lower graph shows the time change of the voltage VL. The time on the horizontal axis corresponds to each step of the process shown in FIG.

  First, when it is detected that the vehicle is stopped (S01, Yes), control device 40 outputs signal SE to system relays SMRB and SMRG, and turns on system relays SMRB and SMRG (S02). For example, control device 40 receives data indicating a rotation angle from a position sensor such as a resolver provided in motor generators MG1 and MG2, and detects the stop of the vehicle based on the rotation angle.

Next, control device 40 outputs switching control signal S _CNV to converter 11 to turn on switching element Q1 on the upper arm side and to turn off switching element Q2 on the lower arm side (S03). When the switching element Q1 on the upper arm side is on, the voltage VL on the DC power supply 10 side of the converter 11 (voltage VL across the capacitor C1) and the voltage VH on the inverters 12 and 13 side of the converter 11 (both ends of the capacitor C2) Voltage VH) is the same. As shown in FIG. 3, during the time corresponding to S03, the voltage VL and the voltage VH are the same, for example, the voltage E1 supplied from the DC power supply 10.

Next, the control device 40 outputs the switching control signal S _CNV to the converter 11 and turns off the upper arm side switching element Q1 with the lower arm side switching element Q2 turned off (S04). As a result, the two switching elements Q1, Q2 are both turned off. In the time corresponding to S04, as shown in FIG. 3, the voltage VL and the voltage VH are the same without changing and are the voltage E1.

  Next, control device 40 outputs signal SE to system relays SMRB and SMRG, and turns off system relays SMRB and SMRG (S05). Thereby, in a state where converter 11 and DC / DC converter 30 are connected, connection between DC power supply 10 and converter 11 is released, and power supply from DC power supply 10 to converter 11 is cut off. Further, the connection between the DC power supply 10 and the DC / DC converter 30 is also released, and the power supply from the DC power supply 10 to the DC / DC converter 30 is cut off.

  Next, the control device 40 outputs a switching control signal to the DC / DC converter 30 to operate the DC / DC converter 30 (S06). As a result, a voltage is supplied from the capacitor C1 to the auxiliary battery 20 via the DC / DC converter 30. As shown in FIG. 3, after the time corresponding to S06, the voltage VL (capacitor) on the DC power supply 10 side of the converter 11 The voltage VL) across C1 gradually decreases.

  Then, the control device 40 compares the voltage VL and the voltage VH, and detects a failure of the switching element Q1 on the upper arm side based on the magnitude relationship between the voltage VL and the voltage VH (S07). For example, when the magnitude relationship between the voltage VH and the voltage VL is “voltage VH> voltage VL” (S07, YES), the control device 40 determines that the switching element Q1 of the upper arm is functioning normally. On the other hand, when the magnitude relationship between the voltage VH and the voltage VL is not “voltage VH> voltage VL” (S07, NO), the control device 40 determines that the switching element Q1 of the upper arm is short-circuited.

  For example, as shown in FIG. 3, when the voltage VH is constant after the time corresponding to S06 and the relationship of “voltage VH> voltage VL” is established (S07, YES), the control device 40 is connected to the upper arm. It is determined that the switching element Q1 is functioning normally. On the other hand, when the voltage VH decreases after the time corresponding to S06 and the relationship of “voltage VH> voltage VL” is not satisfied (S07, NO), the control device 40 has the switching element Q1 of the upper arm short-circuited. Is determined.

  That is, since the two switching elements Q1 and Q2 are turned off after the voltage VH and the voltage VL are set to the constant voltage E1 in S03 while the vehicle is stopped, the DC power supply 10 and the converter 11 Even if the DC / DC converter 30 provided between them is operated, the voltage VH on the inverters 12 and 13 side should not be lowered but kept at a constant voltage E1. When the DC / DC converter 30 is operated in S06, the power supply from the DC power supply 10 is cut off, so that the voltage VL gradually decreases after the time corresponding to S06. Therefore, if the voltage VH is kept constant, the voltage VH is higher than the voltage VL, and the relationship of “voltage VH> voltage VL” should be maintained. Nevertheless, the fact that the relationship of “voltage VH> voltage VL” is not established means that the voltage VH on the inverters 12 and 13 side has decreased. That is, the switching element Q1 on the upper arm side is short-circuited, and the voltage is supplied from the capacitor C2 to the DC power supply 10 side of the converter 11. In this way, a short-circuit failure of the switching element Q1 on the upper arm side can be detected based on the magnitude relationship between the voltage VH and the voltage VL.

  Further, after the time corresponding to S06, the control device 40 determines that the switching element Q1 on the upper arm side is short-circuited when the voltage VH decreases from the voltage E1 together with the voltage VL, and when the voltage VH is constant, It may be determined that the switching element Q1 on the upper arm side is functioning normally.

  When detecting a short circuit failure of switching element Q1, control device 40 may output an abnormality detection signal for notifying the driver of the failure of converter 11 or stop the switching operation of converter 11 and inverters 12 and 13. By doing so, the driving of the vehicle may be prohibited.

  As described above, according to the converter failure detection apparatus according to the present embodiment, it is possible to positively create a situation for detecting a failure of the converter 11 while the vehicle is stopped and to detect the failure of the converter 11. . Thus, it is possible to detect the failure of the converter 11 while the vehicle is stopped, without waiting for the vehicle system to enter a situation for detecting the failure of the converter 11.

  Moreover, according to the converter failure detection apparatus according to the present embodiment, it is possible to detect a failure of the converter 11 without operating the converter 11 so as to function as a booster circuit. Therefore, since it is not necessary to perform boosting in a situation where boosting is not required, it is possible to suppress a decrease in fuel consumption and a decrease in drivability.

  The control device 40 described above is realized by cooperation of hardware resources and software, for example, and is an electronic control unit (ECU: Electronic Control Unit), for example. Specifically, the function of the control device 40 is realized by reading a program recorded on a recording medium into a memory and executing it by a processor such as a CPU (Central Processing Unit). The above program can be provided by being recorded on a computer-readable recording medium, or can be provided by communication as a data signal. The control device 40 may be realized only by hardware. The control device 40 may be physically realized by one device or may be realized by a plurality of devices.

  10 DC power supply, 11 converter, 12, 13 inverter, 14, 15 voltage sensor, 20 auxiliary battery, 30 DC / DC converter, 40 controller, C1, C2 capacitor, D1, D2 diode, L reactor, Q1, Q2 switching Element, MG1, MG2 Motor generator.

Claims (4)

An upper arm side switching element provided between an inverter connected to a motor mounted on a vehicle and a first battery and connected in series between a positive side bus of the inverter and a negative side bus of the inverter And a lower arm side switching element, the voltage from the first battery is boosted by turning on / off the lower arm side switching element and supplied to the inverter, and the upper arm side switching element is turned on / off. A converter failure detection device that detects a failure of a converter that steps down the voltage from the inverter and supplies the first battery by turning off,
A DC / DC converter connected between the first battery and the converter, wherein the second battery supplies a voltage to an auxiliary device mounted on the vehicle having a voltage lower than that of the first battery. And a DC / DC converter for stepping down and supplying a voltage from the first battery;
When the vehicle is stopped, by turning on the upper arm side switching element and turning off the lower arm side switching element, the voltage VL on the first battery side of the converter and the inverter of the converter The first battery in the state where the upper arm side switching element and the lower arm side switching element are turned off and the converter and the DC / DC converter are connected to each other. And the first battery and the DC / DC converter are disconnected, then the DC / DC converter is operated, and the converter is operated based on the voltage VH on the inverter side of the converter. Control means for detecting the failure of
A converter fault detection device comprising: The converter failure detection device according to claim 1,
After the DC / DC converter is operated, the control means detects a failure of the converter based on a magnitude relationship between the voltage VL on the first battery side of the converter and the voltage VH on the inverter side of the converter. To detect,
A converter failure detection device characterized by the above. An upper arm side switching element provided between an inverter connected to a motor mounted on a vehicle and a first battery and connected in series between a positive side bus of the inverter and a negative side bus of the inverter And a lower arm side switching element, the voltage from the first battery is boosted by turning on / off the lower arm side switching element and supplied to the inverter, and the upper arm side switching element is turned on / off. A converter failure detection method for detecting a failure of a converter that steps down a voltage from the inverter and supplies the first battery by turning off,
By turning on the upper arm side switching element and turning off the lower arm side switching element while the vehicle is stopped, the voltage VL on the first battery side of the converter and the inverter of the converter A first step for making the side voltage VH the same;
After the first step, a second step of turning off the upper arm side switching element and the lower arm side switching element and releasing the connection between the first battery and the converter;
After the second step, a DC / DC converter connected between the first battery and the converter, the voltage of which is lower than that of the first battery and installed in the vehicle. A third step of operating a DC / DC converter that steps down the voltage from the first battery and supplies the second battery that supplies the voltage in a state in which the connection with the first battery is released; ,
After the third step, a fourth step of detecting a failure of the converter based on the voltage VH on the inverter side of the converter;
A converter failure detection method comprising: A converter failure detection method according to claim 3,
In the fourth step, after the DC / DC converter is operated, based on the magnitude relationship between the voltage VL on the first battery side of the converter and the voltage VH on the inverter side of the converter, Detect faults,
A converter failure detection method characterized by the above.

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