JP2011234538A - Vehicular drive unit and vehicle equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular drive unit and a vehicle equipped with the same, in which a leakage current can be suppressed when an electrical leak is generated.SOLUTION: The vehicular drive unit includes: an inverter 20 that is connected between a positive electrode bus line PL and a negative electrode bus line NL and drives a motor M1 by a switching operation; an electrical leak detector 70 for detecting an electrical leak in the inverter 20 or the motor M1; and a controller 30 for controlling the inverter 20. When the electrical leak detector 70 detects an electrical leak, the controller 30 controls the inverter 20 by setting a carrier frequency of the inverter 20 lower than when the electrical leak detector 70 detects no electrical leak.

Description

  The present invention relates to a drive device for a vehicle and a vehicle including the same, and more particularly to control at the time of detecting leakage of an electric load of the vehicle.

  Hybrid vehicles (electric vehicles) and electric vehicles (electric vehicles) are attracting great attention as environmentally friendly vehicles.

  This hybrid vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source in addition to a conventional engine. In other words, a power source is obtained by driving the engine, a DC voltage from a DC power source is converted into an AC voltage by an inverter, and a motor is rotated by the converted AC voltage to obtain a power source. An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source.

  Japanese Patent Laying-Open No. 2003-116280 (Patent Document 1) discloses a vehicle including a booster circuit that boosts a battery and an inverter that controls a three-phase AC motor.

JP 2003-116280 A JP 2005-12858 A JP 2005-57918 A

  Such a hybrid vehicle and an electric vehicle are equipped with an electric system for driving wheels, and it is considered to detect whether or not a leakage has occurred in the electric system.

  This electric system includes a high voltage system of 100 V or higher such as an output of a high voltage battery or a booster circuit. When a leakage occurs from the high-voltage system, the chassis ground potential fluctuates due to the leakage current. Due to the fluctuation in the potential of the chassis ground, for example, the DC / DC converter may stop due to malfunction.

  The objective of this invention is providing the drive device of a vehicle which can reduce a leakage current at the time of leakage occurrence, and a vehicle provided with the same.

  In summary, the present invention is a vehicle drive device that is connected between a positive electrode bus and a negative electrode bus and drives a motor by a switching operation, and a leakage detection device that detects a leakage of the inverter or the motor, And a control device for controlling the inverter. When a leakage is detected by the leakage detection device, the control device controls the inverter by lowering the carrier frequency of the inverter as compared with a case where the leakage is not detected by the leakage detection device.

  Preferably, the vehicle includes a power storage device and a voltage converter that converts the voltage of the power storage device and outputs the voltage between the positive bus and the negative bus. When leakage is detected by the leakage detection device, the control device stops the voltage conversion operation by the voltage converter, and causes the voltage converter to output the voltage of the power storage device between the positive electrode bus and the negative electrode bus as it is.

  More preferably, the vehicle further includes an auxiliary battery for supplying electric power to the auxiliary load, and a DC / DC converter for converting the voltage of the power storage device and supplying the converted voltage to the auxiliary battery and the auxiliary load. The control device measures a leakage period in which leakage is detected by the leakage detection device, and stops the operation of the DC / DC converter when the leakage period exceeds the first threshold value.

  More preferably, the control device measures a leakage period in which leakage is detected by the leakage detection device, and if the leakage period exceeds a second threshold value that is greater than the first threshold value, a leakage failure is detected. Record the diagnostic information shown.

  In another aspect, the present invention is a vehicle including any one of the vehicle drive devices described above.

  According to the present invention, since the leakage current is reduced, malfunction of in-vehicle devices such as a DC / DC converter can be prevented.

It is a circuit diagram which shows the structure of the vehicle by this Embodiment. FIG. 2 is a block diagram illustrating an example of a configuration of a DC / DC converter 13 in FIG. 1. It is a flowchart for demonstrating the control which the control apparatus 30 of FIG. 1 performs. It is the figure which showed the change of the actual value of the leakage current at the time of changing the carrier frequency and the boost voltage VH when a ground fault has occurred in the motor. 3 is a flowchart for explaining control of a DC-DC converter control circuit 136 of FIG. It is a figure for demonstrating an example of operation | movement of this Embodiment. It is a figure for demonstrating another example of operation | movement of this Embodiment.

  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.

FIG. 1 is a circuit diagram showing a configuration of a vehicle according to the present embodiment.
Referring to FIG. 1, vehicle 100 includes a high-voltage battery B1 and an auxiliary battery B2, which are both types of DC power supplies, system relays SR1 and SR2, voltage sensors 10 and 16, a voltage converter 11, and a positive bus PL. A negative electrode bus NL, a capacitor 12, a DC / DC converter 13, an air conditioner 14, current sensors 17, 24, an inverter 20, a control device 30, and a leakage detector 70.

  Voltage converter 11 includes a reactor L1, IGBT elements Q1, Q2, and diodes D1, D2. Reactor L1 has one end connected to the positive electrode of high voltage battery B1 and the other end connected to a connection node between the emitter of IGBT element Q1 and the collector of IGBT element Q2.

  IGBT elements Q1, Q2 are connected in series between positive electrode bus PL and negative electrode bus NL. IGBT element Q1 has a collector connected to positive electrode bus PL and an emitter connected to the collector of IGBT element Q2. IGBT element Q2 has an emitter connected to negative electrode bus NL.

  Further, diodes D1 and D2 for passing a current from the emitter side to the collector side are connected between the collector and emitter of the IGBT elements Q1 and Q2, respectively.

  Inverter 20 includes a U-phase arm 21, a V-phase arm 22, and a W-phase arm 23. U-phase arm 21, V-phase arm 22, and W-phase arm 23 are provided in parallel between positive electrode bus PL and negative electrode bus NL.

  U-phase arm 21 includes IGBT elements Q3, Q4 connected in series between positive electrode bus PL and negative electrode bus NL. V-phase arm 22 includes IGBT elements Q5 and Q6 connected in series between positive electrode bus PL and negative electrode bus NL. W-phase arm 23 includes IGBT elements Q7 and Q8 connected in series between positive electrode bus PL and negative electrode bus NL. Further, diodes D3 to D8 that flow current from the emitter side to the collector side are connected between the collectors and emitters of the IGBT elements Q3 to Q8, respectively.

  AC motor M1 is a three-phase permanent magnet motor, and includes U, V, and W phase coils. The intermediate points of the U, V, and W phase arms are respectively connected to one ends of the U, V, and W phase coils of AC motor M1. The other end of the U-phase coil is connected to an intermediate point between IGBT elements Q3 and Q4. The other end of the V-phase coil is connected to an intermediate point between IGBT elements Q5 and Q6. The other end of the W-phase coil is connected to an intermediate point between IGBT elements Q7 and Q8. The other ends of the three coils of the U, V, and W phases are commonly connected to the neutral point.

  Leakage detector 70 includes a coupling capacitor 15, an oscillation circuit 40, a resistor 50, and an impedance determination circuit 60. Coupling capacitor 15 is connected between the negative side of high voltage battery B1 (that is, negative electrode bus NL) and node N1. The resistor 50 is connected between the node N1 and the oscillation circuit 40.

  DC / DC converter 13 and air conditioner 14 are connected in parallel to nodes N 2 and N 3 between system relays SR 1 and SR 2 and voltage converter 11. The auxiliary battery B <b> 2 is connected to the DC / DC converter 13. The negative electrode of auxiliary battery B2 is coupled to chassis ground GND. The auxiliary battery B2 also supplies power to an auxiliary load (not shown). The auxiliary battery B2 can be configured to include a secondary battery such as a lead storage battery or a power storage element such as an electric double layer capacitor.

  The high voltage battery B1 can be configured to include a secondary battery such as nickel metal hydride or lithium ion or a power storage element such as an electric double layer capacitor. High voltage battery B1 supplies DC voltage VB to voltage converter 11, DC / DC converter 13 and air conditioner 14 via system relays SR1 and SR2.

  System relays SR1 and SR2 are turned on / off by a signal SE from control device 30. More specifically, system relays SR1 and SR2 are turned on by H (logic high) level signal SE from control device 30, and are turned off by L (logic low) level signal SE from control device 30.

  Voltage sensor 10 detects DC voltage VB output from high voltage battery B <b> 1 and outputs the detected value of DC voltage VB to control device 30.

  Current sensor 17 detects DC current BCRT input / output to / from high voltage battery B <b> 1, and outputs the detected value of DC current BCRT to control device 30.

  The voltage converter 11 boosts the DC voltage VH from the high voltage battery B 1 based on the signal PWMU from the control device 30 and supplies it to the capacitor 12. The voltage converter 11 steps down the DC voltage supplied from the inverter 20 based on the signal PWMD or PWML from the control device 30 and supplies it to the high voltage battery B1 or the DC / DC converter 13 and the air conditioner 14.

  Capacitor 12 smoothes the DC voltage supplied from voltage converter 11 and supplies it to inverter 20.

  DC / DC converter 13 converts the voltage level of the DC voltage received from high voltage battery B1 or voltage converter 11 and supplies the voltage level to auxiliary battery B2. Air conditioner 14 is driven by a DC voltage received from high voltage battery B1 or voltage converter 11.

  The voltage sensor 16 detects the voltage VH across the capacitor 12 and outputs the detected voltage VH to the control device 30.

  The inverter 20 converts the DC voltage supplied from the voltage converter 11 through the capacitor 12 into an AC voltage based on the signal PWMI from the control device 30, and drives the AC motor M1. Inverter 20 also converts the AC voltage generated by AC motor M 1 into a DC voltage based on signal PWMC from control device 30, and supplies the converted DC voltage to voltage converter 11 via capacitor 12.

  Current sensor 24 detects motor current MCRT flowing through AC motor M <b> 1 and outputs the detected motor current MCRT to control device 30.

  Control device 30 is based on DC voltage VB from voltage sensor 10, voltage VH from voltage sensor 16, motor rotational speed MRN and torque command value TR from an ECU (Electrical Control Unit) provided outside vehicle 100. The signal PWMU or the signal PWMD is generated, and the generated signal PWMU or the signal PWMD is output to the voltage converter 11.

  Further, control device 30 generates signal PWMI or signal PWMC based on voltage VH from voltage sensor 16, motor current MCRT from current sensor 24, and torque command value TR from an external ECU, and the generated signal PWMI. Alternatively, the signal PWMC is output to the inverter 20.

  The oscillation circuit 40 oscillates an AC signal Eo and outputs the oscillated AC signal Eo to the node N1 via the resistor 50. The oscillation circuit 40 outputs an AC signal Eo having a predetermined frequency.

  The impedance determination circuit 60 receives the AC signal E from the node N1, and detects the peak value of the received AC signal E.

  The leakage path from the high voltage system includes a leakage path from the direct current section as indicated by the resistance component 27 to the chassis ground GND, and a leakage path from the alternating current section as indicated by the resistance component 25 and the capacitance component 26 to the chassis ground GND. Conceivable. Here, the determination method of the presence or absence of the electric leakage in an alternating current part is demonstrated.

  When leakage occurs in the AC part of the inverter 20 and the AC motor M1, the leakage impedance corresponds to the impedance in which the resistance component 25 and the capacitance component 26 are connected in parallel. When a leakage occurs in the alternating current section, the alternating current signal Eo output from the oscillation circuit 40 has an impedance (leakage impedance) due to the parallel connection of the resistor 50, the coupling capacitor 15, the resistance component 25 and the capacitance component 26, and The route of chassis ground GND is transmitted.

  Then, the total impedance Z0 of the path is obtained by connecting the resistor 50, the capacitance of the coupling capacitor 15 and the leakage impedance Z in series, but the voltage E at the node N1 indicates whether or not leakage occurs, that is, leakage It is greatly influenced by the impedance Z.

  That is, the peak value (amplitude) of the voltage E changes with the presence or absence of leakage. The impedance determination circuit 60 outputs the peak value of the voltage E as the leakage radio wave peak value DEL. Control device 30 determines that a leakage has occurred in the AC section when leakage radio wave high value DEL is smaller than the threshold value.

  Further, if there is no leakage in the alternating current section, the voltage E is less reduced in amplitude than the voltage Eo. In this case, the leakage radio wave high value is larger than the threshold value, and it is determined that no leakage has occurred in the AC unit.

  When control device 30 receives leakage electric wave high value DEL indicating that leakage has occurred in the AC section of vehicle 100 from leakage detector 70, voltage converter 11 stops the boosting operation as shown in FIG. Is generated, and the generated signal PWML is output to the voltage converter 11. That is, control device 30 controls voltage converter 11 to stop the boosting operation when a leakage occurs in the AC section of vehicle 100.

  Specifically, the voltage converter 11 is controlled so that the upper arm is on. In the upper arm on state, the IGBT element Q2 is controlled to be off and the IGBT element Q1 is controlled to be on. Then, voltage VB is supplied to inverter 20 almost as it is from high voltage battery B1 via reactor L1 and IGBT element Q1. IGBT element Q1 may be turned off. A current can be passed from the high voltage battery B1 to the inverter 20 by the diode D1.

FIG. 2 is a block diagram showing an example of the configuration of the DC / DC converter 13 of FIG.
As shown in FIG. 2, the DC / DC converter 13 receives and smoothes the DC voltage between the nodes N2 and N3 from the high voltage battery B1 in FIG. A DC / AC conversion unit 132 that converts the voltage into a DC voltage, and a step-down transformer 133 that receives the AC voltage converted by the DC / AC conversion unit 132 in the primary coil and steps down the voltage.

  Filter 131 includes capacitors 142 and 144 connected in series between nodes N2 and N3, and a resistor 146 connected between a connection node of capacitors 142 and 144 and chassis ground.

  The DC / DC converter 13 further includes a rectifier circuit 134 that rectifies an alternating voltage induced in the secondary coil of the step-down transformer 133 into a direct current, and a smoothing circuit that smoothes the output of the rectifier circuit 134. A voltage is applied to the auxiliary battery B2 through the smoothing circuit 135, and the auxiliary battery B2 is charged.

  The DC / DC converter 13 further includes an overcurrent / overvoltage detection unit 137 that detects overcurrent and overvoltage, and a DC-DC converter control circuit 136. The detection result of the overcurrent / overvoltage detection unit 137 is given to the DC-DC converter control circuit 136. In response to this, the DC-DC converter control circuit 136 stops or starts the conversion operation of the DC / AC conversion unit 132.

  In the DC-DC converter control circuit 136, the negative electrode of the power supply terminal is connected to the negative electrode of the auxiliary battery B2 via the chassis ground GND, and the positive electrode of the power supply terminal is connected to the auxiliary battery B2. When the potential of the chassis ground GND fluctuates due to leakage or the like, the DC-DC converter control circuit 136 is reset and stops operating.

  FIG. 3 is a flowchart for explaining the control executed by the control device 30 of FIG. The processing of this flowchart is called and executed from a predetermined main routine every predetermined time or every time a predetermined condition is satisfied.

  Referring to FIGS. 1 and 3, control device 30 acquires leakage radio wave high value DEL from impedance determination circuit 60 in step S <b> 1. Subsequently, in step S2, the control device determines whether or not the leakage radio wave high value DEL is smaller than the threshold value β. The leakage electric wave high value DEL is lower than the threshold value β when a leakage occurs.

  In step S2, if the leakage radio wave high value is not smaller than the threshold value β, the process proceeds to step S9. In step S9, the leakage present flag FL is set to OFF. In step S10, the timer that measures the leakage detection time is reset. Thereafter, in step S11, the process is returned to the main routine.

  In step S2, if the leakage radio wave high value is smaller than the threshold value β, the process proceeds to step S3. In step S3, the leakage present flag FL is set to ON. In step S4, the timer for measuring the leakage occurrence detection time is incremented.

  In step S5, control device 30 outputs control signals PWMU, PWMD, and PWML so that boosting by voltage converter 11 is prohibited. Furthermore, the control device 30 reduces the carrier frequency fc of the inverter 20. For example, the carrier frequency fc is selected from 10 kHz, 5 kHz, and 2.5 kHz according to the motor rotation speed, but is lowered to 2.5 kHz, which is the lowest frequency, in step S5. Note that the carrier frequency is not limited to the above frequency, and if a lower carrier frequency is used when leakage occurs compared to the normal carrier frequency, the leakage current can be reduced as described below.

  FIG. 4 is a diagram showing changes in the measured value of the leakage current when the carrier frequency and the boosted voltage VH when the ground fault occurs in the motor are changed.

  Referring to FIG. 4, when the voltage VH is changed from 350 V to 650 V when the carrier frequency of the inverter is 5 kHz, the effective value (Arms) of the leakage current is smaller as the voltage VH is lower. When the carrier frequency of the inverter is changed to 10 kHz, 5 kHz, and 2.5 kHz when the voltage VH is 650 V, the effective value (Arms) of the leakage current is smaller as the carrier frequency is lower. Therefore, in step S5 in FIG. 3, the voltage converter is stopped to raise the voltage VH, and the carrier frequency fc of the inverter 20 is lowered to reduce the leakage current.

  Referring to FIG. 3 again, when the process of step S5 is completed, it is determined in step S6 whether or not the period during which leakage flag FL is on continues for period T1. Thereby, it is detected whether or not there is a voltage fluctuation due to a temporary noise component. If the flag FL on period has not yet continued in period S1 in step S6, control is transferred to the main routine in step S11. If the flag FL on period continues for period T1 in step S6, the process proceeds to step S7.

  In step S7, it is determined that the insulation resistance to the chassis ground of the high-voltage system is reduced, not noise. Based on this determination, operation stop control of the DC / DC converter is performed in FIG. 4 described later. Then, in step S8, it is determined whether or not the period during which leakage flag FL is on continues for period T2. Note that T2> T1.

  In step S8, if the leakage current flag FL is not yet on for the period T2, control is transferred to the main routine in step S11.

  In step S8, if it is confirmed that the leakage current flag FL is on for the period T2, the process proceeds to step S12, and the diagnosis for determining the leakage failure is confirmed and stored, and then the process is performed in step S13. Ends.

  FIG. 5 is a flowchart for explaining the control of the DC-DC converter control circuit 136 of FIG. The processing of this flowchart is called and executed from a predetermined main routine every predetermined time or every time a predetermined condition is satisfied.

  2 and 5, when the process is started, it is determined in step S50 whether or not an overcurrent abnormality is detected. Further, in step S51, it is determined whether or not an overvoltage abnormality is detected. The abnormality detection in steps S50 and S51 is determined based on the output of the overcurrent / overvoltage detection unit 137. Further, in step S52, it is determined whether or not other abnormality is detected. If any abnormality is detected in any of steps S50 to S52, the process proceeds to step S55. If no abnormality is detected, the process proceeds to step S53.

  In step S53, the operation of the DC / DC converter 13 is continued, or when the DC / DC converter 13 is stopped, the operation of the DC / AC converter 132 is restored and the operation is resumed. When the processing in step S53 is completed, control is returned to the main routine in step S54.

  In step S55, it is determined whether a decrease in insulation resistance (ground fluctuation) has been detected. This determination is made based on the determination in step S7 of FIG. Therefore, if the period in which the leakage present flag FL is on is less than the period T1, the flag FL is reset in step S9, so that it is not determined that the insulation resistance has decreased in step S7. When the state in which the flag FL is on continues for the period T1 or more, it is determined in step S55 that the insulation resistance has decreased, and the process proceeds to step S56.

  In step S56, the carrier frequency of the inverter 20 of FIG. 1 is changed, and the voltage converter 11 is stopped from boosting to lower the voltage VH. Then, the determination in step S50 is executed again.

  On the other hand, if a decrease in insulation resistance is not detected in step S55, the process proceeds to step S57 and the DC / DC converter 13 is stopped. At this time, the DC-DC converter control circuit 136 stops the operation of the DC / AC converter 132.

FIG. 6 is a diagram for explaining an example of the operation of the present embodiment.
FIG. 7 is a diagram for explaining another example of the operation of the present embodiment.

  Referring to FIG. 6, until time t0, DC / DC converter 13 is operating, and control device 30 outputs a command for normal operation. At this time, it is assumed that an actual leakage occurs at time t0. Then, the DC / DC converter 13 stops the operation between the times t0 and t1.

  At time t1, the control device 30 determines that the peak value from the leakage detector 70 is smaller than the threshold value and the leakage detection is present. Then, control device 30 sets leakage current flag FL to the ON state in step S3 in FIG. 3, starts incrementing the timer in step S4, prohibits the boosting by voltage converter 11 and determines the carrier frequency of inverter 20 in step S5. Control is performed so that the decrease is executed.

  Then, as described with reference to FIG. 4, the leakage current decreases as the carrier frequency decreases. In response to this, the DC / DC converter 13 resumes operation and becomes operational again after time t1.

  At time t <b> 2 when a period T smaller than time T <b> 1 has elapsed from time t <b> 1, control device 30 again determines whether there is a leakage based on the peak value from leakage detector 70. At time t <b> 2, the control device 30 determines that the peak value from the leakage detector 70 is greater than the threshold value and that there is no leakage detection. As a result, the flag FL is reset in step S9, and the timer is reset in step S10. In addition, control device 30 outputs a command so that normal operation is performed in which the boosted voltage command value is restored and the inverter carrier frequency is also restored.

  In addition, when the leak is still detected at time t2, the cycle from time t1 to t2 is repeated n times, and it is confirmed whether the leak is detected n times. When leakage is detected continuously n times, boosting in the voltage converter 11 is prohibited, and the control is fixed in a state where the carrier frequency of the inverter 20 is lower than usual.

  In such a case, the DC / DC converter 13 stops operating for a moment, but the operation is immediately continued.

On the other hand, the case shown in FIG. 7 is an example in which the control device 30 performs control in two stages.
Referring to FIG. 7, until time t10, DC / DC converter 13 is in operation, and control device 30 outputs a command for normal operation. At this time, it is assumed that an actual leakage occurs at time t10. Then, the DC / DC converter 13 stops its operation from time t10 to t12.

  At time t11, the peak value from leakage detector 70 becomes smaller than the threshold value, and control device 30 determines that leakage detection is present. Then, control device 30 sets leakage current flag FL to the on state, starts incrementing the timer, and prohibits voltage boosting by voltage converter 11 as the first-stage control.

  However, at time t12 when a period longer than the period T1 has elapsed since time t11, it is determined that there is a leakage as a result of reconfirmation of the leakage. The second stage control is performed so that the frequency is lowered. Then, as described with reference to FIG. 4, the leakage current decreases as the carrier frequency decreases. In response to this, the DC / DC converter 13 resumes operation and becomes operational again after time t2.

  After that, at time t13 when a period T (however, T1 <T <T2 in T1 and T2 in FIG. 3) has elapsed from time t11, it is determined again that there is no electric leakage as a result of reconfirmation of electric leakage. The timer is also reset. In addition, control device 30 outputs a command so that normal operation is performed in which the boosted voltage command value is restored and the inverter carrier frequency is also restored.

  In addition, when a leak is still detected at time t13, the cycle from time t11 to t13 is repeated n times, and it is confirmed whether or not the leak is detected n times. When leakage is detected continuously n times, boosting in the voltage converter 11 is prohibited, and the control is fixed in a state where the carrier frequency of the inverter 20 is lower than usual.

  Finally, this embodiment will be summarized with reference to FIG. 1 again. The vehicle drive apparatus according to the present embodiment is connected between positive electrode bus PL and negative electrode bus NL, and includes inverter 20 that drives motor M1 by a switching operation, and a leak detector that detects a leak in inverter 20 or motor M1. 70 and a control device 30 for controlling the inverter 20. When leakage is detected by leakage detector 70, control device 30 controls inverter 20 by lowering the carrier frequency of inverter 20 compared to the case where leakage is not detected by leakage detector 70. For example, when the carrier frequency can be switched to 10 kHz, 5 kHz, and 2.5 kHz, the minimum frequency of 2.5 kHz is selected as the carrier frequency when leakage is detected.

  Preferably, vehicle 100 includes a high voltage battery B1 and a voltage converter 11 that converts the voltage of high voltage battery B1 and outputs the voltage between positive electrode bus PL and negative electrode bus NL. As shown in FIG. 3, when leakage is detected by leakage detector 70 (YES in step S <b> 2), control device 30 stops voltage conversion operation by voltage converter 11 (step S <b> 5), and voltage converter 11. Then, the voltage of the high voltage battery B1 is directly output between the positive electrode bus PL and the negative electrode bus NL.

  More preferably, vehicle 100 includes an auxiliary battery B2 for supplying electric power to the auxiliary load, and a DC / DC converter that converts the voltage of high voltage battery B1 and supplies the voltage to auxiliary battery B2 and the auxiliary load. In addition. As shown in FIG. 3, the control device 30 measures the leakage period in which leakage is detected by the leakage detector 70, and if the leakage period exceeds the first threshold value T1 (YES in step S6 → In step S7, YES), the operation of the DC / DC converter 13 is stopped.

  In the present embodiment, the control device 30 determines the decrease in insulation resistance in steps S6 and S7 in the flowchart of FIG. 3, but this determination is performed by the DC-DC converter control circuit 136 inside the DC / DC converter 13. You can do it. Further, this determination may be performed by both the control device 30 and the DC-DC converter control circuit 136. In the present embodiment, the control device 30 and the DC-DC converter control circuit 136 inside the DC / DC converter 13 are separated, but they may be combined into one control device.

  More preferably, as shown in FIG. 3, control device 30 measures a leakage period in which leakage is detected by leakage detector 70, and the second threshold value is greater than first threshold value T <b> 1. If T2 is exceeded (YES in step S8), diagnostic information indicating a leakage fault is recorded (step S12).

  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.

  10, 16 voltage sensor, 11 voltage converter, 12, 142, 144 capacitor, 13 DC / DC converter, 14 air conditioner, 15 coupling capacitor, 17, 24 current sensor, 20 inverter, 21, 22, 23 arm, 30 controller , 40 oscillation circuit, 50, 146 resistance, 60 impedance determination circuit, 70 leakage detector, 100 vehicle, 131 filter, 132 converter, 133 step-down transformer, 134 rectifier circuit, 135 smoothing circuit, 136 DC-DC converter control circuit, 137 Overvoltage detection unit, B1 high voltage battery, B2 auxiliary battery, BCRT DC current, D1-D8 diode, L1 reactor, M1 motor, N1, N2, N3 node, NL, PL bus, Q1-Q8 IGBT element, SR1, R2 system relay.

Claims (5)

A drive device for a vehicle,
An inverter connected between the positive electrode bus and the negative electrode bus and driving the motor by a switching operation;
A leakage detection device for detecting leakage of the inverter or the motor;
A control device for controlling the inverter,
When the leakage is detected by the leakage detection device, the control device controls the inverter by lowering the carrier frequency of the inverter compared to the case where leakage is not detected by the leakage detection device. Vehicle drive device. The vehicle is
A power storage device;
A voltage converter that converts the voltage of the power storage device and outputs the voltage between the positive electrode bus and the negative electrode bus,
When leakage is detected by the leakage detection device, the control device stops the voltage conversion operation by the voltage converter, and causes the voltage converter to directly use the voltage of the power storage device between the positive bus and the negative bus. The vehicle drive device according to claim 1, wherein the vehicle drive device is output in between. The vehicle is
An auxiliary battery for supplying power to the auxiliary load;
A DC / DC converter that converts the voltage of the power storage device and supplies the voltage to the auxiliary battery and the auxiliary load;
The control device measures a leakage period in which leakage is detected in the leakage detection device, and stops the operation of the DC / DC converter when the leakage period exceeds a first threshold value. Item 3. The vehicle drive device according to Item 2.   The control device measures a leakage period in which leakage is detected in the leakage detection device, and if the leakage period exceeds a second threshold value that is greater than the first threshold value, a leakage failure is detected. The vehicle drive device according to claim 3, wherein diagnostic information is recorded.   A vehicle comprising the vehicle drive device according to claim 1.

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