JP6365324B2 - Automobile - Google Patents

Description

  The present invention relates to an automobile, and more particularly, a control means for controlling an inverter that drives a motor for traveling by a pulse width modulation control method, and a decrease in insulation resistance that detects a decrease in insulation resistance by application of an electric signal from an oscillation power source. And a detection device.

  2. Description of the Related Art Conventionally, as this type of automobile, an automobile is proposed that includes an insulation resistance decrease detection device that is connected to the negative electrode of a battery and detects a decrease in insulation resistance of an electrical system connected to the battery (for example, Patent Document 1). reference). In this automobile, a power control device such as an inverter or relay having a power cut-off function attached to an electric system is changed between a power cut-off state and a power non-cut-off state, and insulation resistance decreases before and after the state transition. Based on the magnitude of the change in the output of the detection device, the location where the insulation resistance is reduced is identified.

JP 2014-36467 A

  In the insulation resistance drop detecting device mounted on the automobile described above, if the insulation resistance at the normal time is designed to be the minimum necessary, it becomes difficult to distinguish between the normal time and the abnormal time due to variations in the output characteristics of the device. For this reason, if the filter circuit configured by the hardware circuit is replaced with a digital filter by software, variation in output characteristics of the apparatus can be reduced, and the normal time and the abnormal time can be more accurately distinguished. However, if the filter circuit by the hardware circuit is replaced with a digital filter by software, the waveform (voltage amplitude) input to the device increases due to noise superimposition, the input waveform becomes overrange, and a decrease in insulation resistance is erroneously detected. Cases arise.

  The main object of the automobile of the present invention is to suppress erroneous detection of a decrease in insulation resistance.

  The automobile of the present invention has taken the following means in order to achieve the main object described above.

The automobile of the present invention
A normal PWM control and a fundamental wave for controlling the inverter by a pulse width modulation control method using a predetermined position in the amplitude of the carrier wave as the amplitude center of the fundamental wave, a motor for driving, a battery, an inverter for driving the motor A control means for performing center-shifted PWM control for controlling the inverter by a pulse width modulation control system with a change from the predetermined position, and an electrical signal from an oscillation power supply, and is connected to the battery. In an automobile equipped with an insulation resistance decrease detection device that detects a decrease in insulation resistance of an electrical system,
The control means reduces the insulation resistance when the rotational speed of the motor is within a predetermined rotational speed range that is greater than or equal to a first threshold value of a relatively low revolution and less than or equal to a second threshold value, or when performing the center shifting PWM control. A means for prohibiting detection of a decrease in insulation resistance by the detection device.
It is characterized by that.

  In this automobile of the present invention, the control means uses normal PWM control for controlling the inverter by a pulse width modulation control method using a predetermined position in the amplitude of the carrier wave as the amplitude center of the fundamental wave, and the amplitude center of the fundamental wave from the predetermined position. With this change, the center shift PWM control for controlling the inverter by the pulse width modulation control system is executed to drive the motor. On the other hand, the insulation resistance decrease detection device detects a decrease in insulation resistance of an electrical system connected to the battery using an electrical signal from the oscillation power supply. Then, the control means performs insulation when the rotational speed of the motor is within a predetermined rotational speed range between the first threshold value and the second threshold value of the relatively low speed, or when the inverter is shifted from the center and PWM control is executed. The detection of a decrease in insulation resistance by a resistance decrease detector is prohibited. Here, the predetermined rotation speed range is determined by experiments or the like as a motor rotation speed range in which the insulation resistance decrease detection device may erroneously detect a decrease in insulation resistance due to noise caused by the rotation of the motor. The first threshold multiplied by the number of motor pole pairs and the number of phases is smaller than the oscillation frequency of the oscillation power supply, and the second threshold multiplied by the number of motor pole pairs and the number of phases is the oscillation frequency of the oscillation power supply. It is determined to be larger. Therefore, it is possible to suppress erroneous detection of a decrease in insulation resistance by prohibiting detection of a decrease in insulation resistance by the insulation resistance decrease detection device when the number of rotations of the motor is within a predetermined rotation number range. In the center shift PWM control, since the amplitude center of the fundamental wave is periodically changed from a predetermined position, the noise amplitude may be superimposed depending on the cycle. When the noise amplitude is superimposed, there is a possibility of erroneous detection in the detection of the decrease in insulation resistance by the insulation resistance decrease detection device. Therefore, it is possible to suppress erroneous detection of a decrease in insulation resistance by prohibiting detection of a decrease in insulation resistance by the insulation resistance decrease detection device when the center shift PWM control is being executed.

1 is a configuration diagram illustrating an outline of a configuration of a hybrid vehicle 20 including a vehicle according to an embodiment of the present invention. It is a block diagram which shows the outline of a structure of the electric drive system containing motor MG1, MG2. It is explanatory drawing which shows the insulation resistance fall detection apparatus 90 and the simple model 95 of the type | system | group to which this insulation resistance fall detection apparatus 90 was connected. It is explanatory drawing which shows an example of the relationship between the insulation resistance between a diagnostic target and a vehicle body, and the amplitude of the voltage detected by the voltage sensor 94. It is explanatory drawing which shows an example of center shift PWM control. It is a flowchart which shows an example of the insulation resistance fall detection permission prohibition process performed by HVECU70 of an Example. It is explanatory drawing which shows an example of an insulation resistance fall detection prohibition area | region.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 including an automobile as an embodiment of the present invention, and FIG. 2 is a configuration diagram showing an outline of the configuration of an electric drive system including motors MG1 and MG2. It is. As shown in FIG. 1, the hybrid vehicle 20 of the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a boost converter 55, a high voltage battery 50, and a system main relay 56. And a low voltage battery 60, a DC / DC converter 62, an insulation resistance drop detecting device 90, and a hybrid electronic control unit (hereinafter referred to as HVECU) 70.

  The engine 22 is configured as an internal combustion engine that outputs power using gasoline or light oil as a fuel. Operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as engine ECU) 24.

  Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The engine ECU 24 receives signals from various sensors necessary for controlling the operation of the engine 22, for example, a crank angle θcr from a crank position sensor that detects the rotational position of the crankshaft 26, and the like via an input port. Yes. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 through an output port. The engine ECU 24 is connected to the HVECU 70 via a communication port, controls the operation of the engine 22 by a control signal from the HVECU 70, and outputs data related to the operating state of the engine 22 to the HVECU 70 as necessary. The engine ECU 24 calculates the rotational speed of the crankshaft 26, that is, the rotational speed Ne of the engine 22, based on the crank angle θcr from the crank position sensor.

  The planetary gear 30 is configured as a single pinion type planetary gear mechanism. The sun gear, the ring gear, and the carrier of the planetary gear 30 are connected to the rotor of the motor MG1, the drive shaft 36 coupled to the drive wheels 38a and 38b via the differential gear 37, and the crankshaft 26 of the engine 22, respectively.

  The motor MG1 is configured as a synchronous generator motor having a rotor in which a permanent magnet is embedded and a stator in which a three-phase coil is wound, and the rotor is connected to the sun gear of the planetary gear 30 as described above. Yes. The motor MG2 is configured as a synchronous generator motor similar to the motor MG1, and the rotor is connected to the drive shaft 36.

  As shown in FIG. 2, the inverter 41 is connected to the drive voltage system power line 54a. The inverter 41 includes six transistors T11 to T16 and six diodes D11 to D16 connected in parallel to the transistors T11 to T16 in the reverse direction. Two transistors T11 to T16 are arranged in pairs so as to be on the source side and the sink side with respect to the positive and negative buses of the drive voltage system power line 54a, respectively. In the transistors T11 to T16, each of the three-phase coils (U-phase, V-phase, W-phase) of the motor MG1 is connected to each connection point between the paired transistors. Therefore, when a voltage is applied to the inverter 41, the motor electronic control unit (hereinafter referred to as a motor ECU) 40 adjusts the ratio of the on-time of the paired transistors T11 to T16, so that three-phase A rotating magnetic field is formed in the coil, and the motor MG1 is driven to rotate. Similarly to the inverter 41, the inverter 42 includes six transistors T21 to T26 and six diodes D21 to D26. When the voltage is applied to the inverter 42, the motor ECU 40 adjusts the ratio of the on-time of the paired transistors T21 to T26, whereby a rotating magnetic field is formed in the three-phase coil, and the motor MG2 is Driven by rotation.

  As shown in FIG. 2, boost converter 55 is connected to drive voltage system power line 54 a to which inverters 41 and 42 are connected, and to battery voltage system power line 54 b to which high voltage battery 50 is connected. This step-up converter 55 includes two transistors T31 and T32, two diodes D31 and D32 connected in parallel to the transistors T31 and T32 in the reverse direction, and a reactor L. The transistor T31 is connected to the positive bus of the drive voltage system power line 54a. The transistor T32 is connected to the transistor T31 and the negative bus of the drive voltage system power line 54a and the battery voltage system power line 54b. Reactor L is connected to a connection point between transistors T31 and T32 and a positive electrode bus of battery voltage system power line 54b. The boost converter 55 boosts the power of the battery voltage system power line 54b and supplies it to the drive voltage system power line 54a by turning on and off the transistors T31 and T32 by the motor ECU 40, or the power of the drive voltage system power line 54a. Or the voltage is supplied to the battery voltage power line 54b. A smoothing capacitor 57 is attached to the positive electrode side line and the negative electrode side line of the drive voltage system power line 54a, and a smoothing capacitor 57 is attached to the positive electrode side line and the negative electrode side line of the battery voltage system power line 54b. A capacitor 58 is attached. Further, a discharge resistor 59 is attached to the positive electrode side line and the negative electrode side line of the drive voltage system power line 54a.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . As shown in FIG. 1, the motor ECU 40 detects signals from various sensors necessary for driving and controlling the motors MG1, MG2 and the boost converter 55, for example, a rotation for detecting the rotational position of the rotor of the motors MG1, MG2. The rotational position θm1, θm2 from the position detection sensor, the phase current from the current sensor that detects the current flowing in each phase of the motors MG1, MG2, the voltage of the capacitor 57 from the voltage sensor 57a attached between the terminals of the capacitor 57 ( The voltage of the drive voltage system power line 54a) VH, the voltage of the capacitor 58 (voltage of the battery voltage system power line 54b) VL from the voltage sensor 58a attached between the terminals of the capacitor 58, etc. are input via the input port. Yes. Further, the motor ECU 40 outputs switching control signals to the transistors T11 to T16 and T21 to T26 of the inverters 41 and 42, switching control signals to the transistors T31 and T32 of the boost converter 55, and the like through the output port. . The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 controls driving of the motors MG1, MG2 and the boost converter 55 by a control signal from the HVECU 70 and drives the motors MG1, MG2 and the boost converter 55 as necessary. Is output to the HVECU 70. The motor ECU 40 calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position detection sensor.

  The high voltage battery 50 is configured as, for example, a lithium ion secondary battery or nickel hydride secondary battery of 200V or 250V, and is connected to the battery voltage system power line 54b as described above. The high voltage battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52.

  Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The battery ECU 52 is connected to signals necessary for managing the high voltage battery 50, for example, the battery voltage Vb from the voltage sensor 51 installed between the terminals of the high voltage battery 50, and the output terminal of the high voltage battery 50. The battery current Ib from the current sensor attached to the power line, the battery temperature Tb from the temperature sensor attached to the high voltage battery 50, and the like are input via the input port. The battery ECU 52 is connected to the HVECU 70 via a communication port, and outputs data relating to the state of the high voltage battery 50 to the HVECU 70 as necessary. The battery ECU 52 is a ratio of the capacity of electric power that can be discharged from the high-voltage battery 50 at that time based on the integrated value of the battery current Ib detected by the current sensor in order to manage the high-voltage battery 50. Input / output limits Win and Wout, which are maximum allowable powers that may charge / discharge the high-voltage battery 50 based on the calculated storage ratio SOC or based on the calculated storage ratio SOC and the battery temperature Tb detected by the temperature sensor. It is calculating.

  As shown in FIG. 2, the system main relay 56 is provided closer to the high voltage battery 50 than the capacitor 58 of the battery voltage system power line 54b. This system main relay 56 includes a positive side relay SMRB provided on the positive side line of the battery voltage system power line 54b, a negative side relay SMRG provided on the negative side line of the battery voltage system power line 54b, and a negative side relay. A precharge circuit in which a precharge resistor R and a precharge relay SMRP are connected in series so as to bypass the SMRG. The system main relay 56 is turned on and off by the HVECU 70.

  The low voltage battery 60 is configured as, for example, a 12V lead acid battery, and is connected to a power line (hereinafter referred to as a low voltage system power line) 54c together with a low voltage auxiliary machine (not shown). The DC / DC converter 62 is connected from the system main relay 56 of the battery voltage system power line 54b to the boost converter 55 side and the low voltage system power line 54c. This DC / DC converter 62 is controlled by the HVECU 70 to step down the power of the battery voltage system power line 54b and supply it to the low voltage system power line 54c, or boost the power of the low voltage system power line 54c. Or supplied to the battery voltage system power line 54b.

  The insulation resistance decrease detection device 90 is connected to the negative terminal of the high voltage battery 50. As shown in FIG. 2, the insulation resistance drop detecting device 90 includes an oscillation power supply 91 grounded on one side, a detection resistor 92 connected to the oscillation power supply 91 on one side, and a detection resistor 92 on one side. The voltage at the connection between the coupling capacitor 93 connected to the other terminal and the other terminal connected to the negative terminal of the high voltage battery 50, and the detection resistor 92 and the coupling capacitor 93 is detected and output to the HVECU 70. Voltage sensor 94.

  FIG. 3 is an explanatory diagram showing an insulation resistance decrease detecting device 90 and a simplified model 95 of a system to which the insulation resistance decrease detecting device 90 is connected. The simple model 95 is a circuit model of a portion (hereinafter referred to as a diagnosis target) connected to the insulation resistance lowering detection device 90 in the entire high voltage system. Here, as the high voltage system, in the embodiment, motors MG1, MG2, inverters 41, 42, high voltage battery 50, boost converter 55, system main relay 56, capacitors 57, 58, drive voltage system power line 54a, and battery. This corresponds to the voltage system power line 54b. The diagnosis target is the entire high-voltage system when at least one of the positive relay SMRB, the negative relay SMRG, and the precharge relay SMRP of the system main relay 56 is on, and the positive relay SMRB of the system main relay 56, When all of the negative side relay SMRG and the precharge relay SMRP are off, the part is on the high voltage battery 50 side (hereinafter referred to as the battery part) from the system main relay 56. Hereinafter, the inverters 41 and 42 from the system main relay 56 are referred to as an inverter unit. This simple model 95 is composed of an insulation resistor 96 having one terminal connected to the coupling capacitor 93 and the other terminal grounded, and a common mode capacitor 97 connected in parallel to the insulation resistor 96. The FIG. 4 is an explanatory diagram showing an example of the relationship between the insulation resistance between the diagnosis target and the vehicle body and the amplitude of the voltage detected by the voltage sensor 94. When the simple model 95, that is, the impedance to be diagnosed is large, almost no current flows through the detection resistor 92. Therefore, the voltage waveform detected by the voltage sensor 94 at this time is a voltage waveform having substantially the same amplitude as that of the oscillation power supply 91. On the other hand, when the impedance of the simple model 95 is small, a current flows through the detection resistor 92. For this reason, the voltage waveform detected by the voltage sensor 94 at this time is a voltage waveform having an amplitude smaller than that of the oscillation power supply 91 by the voltage drop caused by the detection resistor 92. Therefore, the voltage sensor 94 outputs a voltage waveform having substantially the same amplitude as that of the oscillation power supply 91 to the HVECU 70 when the insulation resistance of the simple model 95, that is, the diagnosis target is not reduced, and the insulation resistance of the simple model 95, that is, the diagnosis object. When the voltage is lowered, a voltage waveform having an amplitude smaller than that of the oscillation power supply 91 is output to the HVECU 70. In the embodiment, when the amplitude of the voltage waveform is equal to or larger than the threshold for determination set in advance as a value slightly smaller than the amplitude of the voltage waveform of the oscillation power supply 91 by the HVECU 70, the insulation resistance with respect to the body to be diagnosed is not reduced (decrease). When the amplitude of the voltage waveform to be diagnosed is smaller than the threshold for determination, it is determined that the insulation resistance with respect to the vehicle body to be diagnosed is reduced (decrease is detected). In addition, as a factor of the fall of the insulation resistance with respect to the vehicle body to be diagnosed, a foreign substance such as metal, cooling water of the HV unit cooling device that cools the motors MG1 and MG2, the inverters 41 and 42, rainwater, and the like can be considered.

  Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. The HVECU 70 includes a signal (voltage waveform) from the insulation resistance lowering detection device 90, an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and depression of the accelerator pedal 83. The accelerator opening Acc from the accelerator pedal position sensor 84 for detecting the amount, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, etc. via the input port. Have been entered. The HVECU 70 outputs an on / off control signal to the system main relay 56 through an output port. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. Note that, as described above, the HVECU 70 uses the output from the voltage sensor 94 (the amplitude of the voltage waveform) to determine whether or not the insulation resistance with respect to the diagnosis target vehicle body is reduced (decrease is detected). To do.

  The thus configured hybrid vehicle 20 of the embodiment travels in a hybrid travel mode (HV travel) that travels with the operation of the engine 22 or in an electric travel mode (EV travel) that travels while the operation of the engine 22 is stopped.

  During travel in the HV travel mode, the HVECU 70 sets the required torque Tr * required for travel based on the accelerator opening Acc and the vehicle speed V, and sets the rotational speed Nr ( For example, the traveling power Pdrv * required for traveling is calculated by multiplying the rotational speed Nm2 of the motor MG2 and the rotational speed obtained by multiplying the vehicle speed V by a conversion factor), and the battery 50 is calculated from the calculated traveling power Pdrv *. The required power Pe * required for the vehicle is set by subtracting the charge / discharge required power Pb * (a positive value when discharging from the battery 50) based on the storage ratio SOC. The required power Pe * is output from the engine 22 and the required torque Tr * is output to the drive shaft 36 within the range of the input / output limits Win and Wout of the battery 50. Torque Te *, torque commands Tm1 * and Tm2 * for motors MG1 and MG2 are set, and drive voltage is set so that motors MG1 and MG2 can be driven at a target drive point consisting of rotation speeds Nm1 and Nm2 and torque commands Tm1 * and Tm2 *. Voltage command VH * for system power line 54a is set and transmitted to engine ECU 24 and motor ECU 40. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te *, controls the intake air amount, fuel injection control, and ignition of the engine 22 so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te *. The motor ECU 40 that receives the torque commands Tm1 * and Tm2 * and the voltage command VH * performs control and the like, and switches the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. Control is performed and switching control of the switching element of the boost converter 55 is performed so that the voltage VH of the drive voltage system power line 54a becomes the voltage command VH *. During traveling in the HV traveling mode, when the stop condition of the engine 22 is satisfied, for example, when the required power Pe * is less than the stop threshold value Pstop, the operation of the engine 22 is stopped and the traveling in the EV traveling mode is performed. Transition.

  During travel in the EV travel mode, the HVECU 70 sets a required torque Tr * based on the accelerator opening Acc and the vehicle speed V, sets a value 0 to the torque command Tm1 * of the motor MG1, and limits input / output of the battery 50. The torque command Tm2 * of the motor MG2 is set so that the required torque Tr * is output to the drive shaft 36 within the range of Win and Wout, and the voltage command of the drive voltage system power line 54a is set in the same manner as when traveling in the HV traveling mode. VH * is set and transmitted to the motor ECU 40. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. Switching control of the switching element of the boost converter 55 is performed so that the voltage VH of the line 54a becomes the voltage command VH *. When traveling in the EV traveling mode, the engine 22 is turned on when the engine 22 starting condition is satisfied, for example, when the required power Pe * calculated in the same manner as in the traveling in the HV traveling mode reaches a starting threshold value Pstart or more. Start and shift to traveling in the HV traveling mode.

  Here, control of the inverters 41 and 42 will be described. In the embodiment, the inverters 41 and 42 are sine wave control type, overmodulation according to the voltage VH of the drive voltage system power line 54a, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2, and the torque commands Tm1 * and Tm2 *. Control was performed by either the control method or the rectangular wave control method. In the sine wave control method, the pulse width modulation (PWM) control that adjusts the ratio of the on-time of a plurality of switching elements by comparing the voltage command of the motors MG1 and MG2 and the triangular wave (carrier wave) voltage is less than the amplitude of the triangular wave voltage. In this control system, a pseudo three-phase AC voltage obtained by converting a voltage command having a sinusoidal amplitude is supplied to the motors MG1 and MG2. The overmodulation control system is a control system that supplies an overmodulation voltage obtained by converting a sinusoidal voltage command having an amplitude larger than the amplitude of the triangular wave voltage to the motors MG1 and MG2 in the pulse width modulation control. Furthermore, the rectangular wave control method is a control method for supplying a rectangular wave voltage to the motors MG1 and MG2. In the embodiment, in the sine wave control method, the frequency of the triangular wave voltage (carrier frequency) is changed according to the rotational speeds Nm1, Nm2 of the motors MG1, MG2 and the torque commands Tm1 *, Tm2 *, and a pseudo three-way control is performed by pulse width modulation. A phase AC voltage is supplied to the motors MG1 and MG2, but when the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are small, a relatively low carrier frequency (frequency fref) is used to set the amplitude center of the sinusoidal voltage command as a triangular wave voltage. A pseudo three-phase AC voltage is supplied to the motors MG1 and MG2 by pulse width modulation by shifting with respect to the amplitude of the motor MG1. In the embodiment, the pulse width modulation by shifting the amplitude center of the sinusoidal voltage command with respect to the amplitude of the triangular wave voltage is referred to as center-shifted PWM control. FIG. 5 shows an example of temporal changes of the u-phase sine wave voltage command, the triangular wave voltage, and the pseudo three-phase AC voltage during the center shift PWM control. FIG. 5A shows the case where the amplitude center (center) of the sinusoidal voltage command is the center (0.50) of the amplitude of the triangular wave voltage, and FIG. 5B shows the sinusoidal voltage command. Is the center of the amplitude of the triangular wave voltage (0.25). As shown in the figure, the duty ratio of the pseudo three-phase AC voltage applied to the motor can be changed by changing the position of the amplitude center (center) of the sinusoidal voltage command with respect to the amplitude of the triangular wave voltage.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when permitting or prohibiting the detection of the decrease in insulation resistance by the insulation resistance decrease detection device 90 will be described. FIG. 6 is a flowchart illustrating an example of the insulation resistance reduction detection permission prohibition process executed by the HVECU 70 of the embodiment. This routine is executed prior to this detection when detecting a decrease in insulation resistance by the insulation resistance decrease detection device 90, for example.

  When the insulation resistance decrease detection permission prohibition process is executed, first, the HVECU 70 executes a process of inputting the torque command Tm2 * of the motor MG2, the rotation speed Nm2, and the carrier frequency fmg2 of the inverter 42 (step S100). Next, it is determined whether or not torque is output from the motor MG2 (step S110), and when the torque is not output from the motor MG2, the reason why the detection of the decrease in insulation resistance by the insulation resistance decrease detection device 90 is prohibited. This process is terminated. Here, whether or not torque is output from motor MG2 can be determined by whether or not value 0 is set in torque command Tm2 * of motor MG2.

  When it is determined that torque is output from the motor MG2, it is determined whether or not the rotational speed Nm2 of the motor MG2 is within a predetermined rotational speed range that is greater than or equal to the first threshold value Nref1 and less than the second threshold value Nref2 (step S120). ), It is determined whether or not the carrier frequency fmg2 of the inverter 42 that drives the motor MG2 is the frequency fref for performing the center-shifted PWM control (step S130). Here, the predetermined rotation speed range is a range of the rotation speed Nm2 of the motor MG2 in which the insulation resistance decrease detection device 90 may erroneously detect a decrease in insulation resistance with respect to noise caused by the rotation of the motor MG2. It is determined by. Therefore, there is a possibility of erroneous detection in the detection of the decrease in insulation resistance by the insulation resistance decrease detection device 90 when the rotation speed Nm2 of the motor MG2 is in the predetermined rotation speed range. In the embodiment, the value obtained by multiplying the first threshold value Nref, which is the lower limit value of the predetermined rotational speed range, by the number of pole pairs and the phase number of the motor MG2 is smaller than the oscillation frequency of the oscillation power supply 91 and is the upper limit value. A value obtained by multiplying Nref by the number of pole pairs and the number of phases of the motor MG2 is determined to be larger than the oscillation frequency of the oscillation power supply. Since the center shift PWM control is performed by periodically changing the amplitude center of the sinusoidal voltage command from the amplitude center of the triangular wave voltage, the noise amplitude is superimposed and input to the insulation resistance lowering detection device 90 according to the cycle. Occurs. When the noise amplitude is superimposed, there is a possibility of erroneous detection in the detection of the decrease in insulation resistance by the insulation resistance decrease detection device 90. In the embodiment, when the carrier frequency of the inverter 42 that drives the motor MG2 is the frequency fref, the center 42 is shifted with respect to the inverter 42 and PWM control is performed. Therefore, the determination as to whether or not the carrier frequency of the inverter 42 is the frequency fref is the same as the determination as to whether or not the center-shifted PWM control is being performed with respect to the inverter 42.

  When it is determined in steps S120 and S130 that the rotational speed Nm2 of the motor MG2 is not within the predetermined rotational speed range and the carrier frequency fmg2 is determined not to be the frequency fref, the insulation resistance decrease by the insulation resistance decrease detection device 90 is reduced. It is determined that there is no possibility of erroneous detection, and detection of a decrease in insulation resistance by the insulation resistance decrease detection device 90 is permitted (step S140), and this process ends. On the other hand, when the rotation speed Nm2 of the motor MG2 is within the predetermined rotation speed range or the carrier frequency fmg2 is the frequency fref, there is a possibility of erroneous detection in the detection of the decrease in insulation resistance by the insulation resistance decrease detection device 90. It is determined that there is, and detection of a decrease in insulation resistance by the insulation resistance decrease detection device 90 is prohibited (step S150), and this process is terminated. FIG. 7 shows an example of the insulation resistance decrease detection prohibition region with respect to the carrier frequency and the rotational speed Nm2 of the motor MG2. As shown in the figure, the insulation resistance decrease detection prohibition region is when the rotational speed Nm2 of the motor MG2 is within a predetermined rotational speed range, or when the carrier frequency fmg2 is the frequency fref.

  In the hybrid vehicle 20 of the embodiment described above, when the torque is output from the motor MG2, the rotation speed Nm2 of the motor MG2 is erroneously detected by the insulation resistance decrease detection device 90 with respect to noise. It is determined whether or not the motor MG2 is in a predetermined rotation speed range (Nref1 ≦ Nm2 <Nref2) defined as a range of the rotation speed Nm2 of the motor MG2. At the same time, it is determined whether or not the carrier frequency fmg2 of the inverter 42 that drives the motor MG2 is the frequency fref for shifting the center and executing the PWM control. When the rotation speed Nm2 of the motor MG2 is in the predetermined rotation speed range or when the carrier frequency fmg2 is the frequency fref, the detection of the decrease in insulation resistance by the insulation resistance decrease detection device 90 is prohibited. Thereby, it can suppress that the fall of insulation resistance is erroneously detected by the insulation resistance fall detection apparatus 90. FIG.

  Although the hybrid vehicle 20 of the embodiment includes the boost converter 55 connected to the drive voltage system power line 54a and the battery voltage system power line 54b, it may not include this.

  In the embodiment, the configuration of the hybrid vehicle 20 including the engine 22, the planetary gear 30, the motors MG1 and MG2, and the high-voltage battery 50 has been described. However, the engine and the output shaft of the engine are connected to each other via a clutch and are driven wheels. It is good also as a structure of what is called a 1 motor hybrid vehicle provided with the motor connected to the drive shaft connected to through the transmission, and the battery which exchanges electric power with a motor. Moreover, it is good also as a structure of the electric vehicle which is not provided with an engine and drive | works using only the motive power from a motor.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor MG2 corresponds to “motor”, the battery 50 corresponds to “battery”, the inverter 42 corresponds to “inverter”, the HVECU 70 and the motor ECU 40 correspond to “control means”, and the insulation resistance The decrease detection device 90 corresponds to an “insulation resistance decrease detection device”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. In other words, the interpretation of the invention described in the column of means for solving the problem should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problem. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention is applicable to the automobile manufacturing industry.

  20 hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 40 motor electronic control unit (motor ECU), 41, 42 Inverter, 50 High voltage battery, 51 Voltage sensor, 52 Battery electronic control unit (battery ECU), 54a Drive voltage system power line, 54b Battery voltage system power line, 54c Low voltage system power line, 55 Boost converter, 56 system main relay, 57, 58 capacitor, 57a, 58a voltage sensor, 59 discharge resistance, 60 low voltage battery, 62 DC / DC converter, 70 hybrid electronic control unit (HVECU), 80 Ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 90 insulation resistance drop detection device, 91 oscillation power supply, 92 detection resistance , 93 Coupling capacitor, 94 Voltage sensor, 95 Simple model, 96 Insulation resistance, 97 Common mode capacitor, L reactor, MG1, MG2 motor, SMRB positive side relay, SMRG negative side relay, SMRP precharge relay, R precharge Resistors, T11-T16, T21-T26, T31, T32 transistors, D11-D16, D21-D26, D31, D32 diodes.

Claims (1)

A normal PWM control and a fundamental wave for controlling the inverter by a pulse width modulation control method using a predetermined position in the amplitude of the carrier wave as the amplitude center of the fundamental wave, a motor for driving, a battery, an inverter for driving the motor A control means for performing center-shifted PWM control for controlling the inverter by a pulse width modulation control system with a change from the predetermined position, and an electrical signal from an oscillation power supply, and is connected to the battery. In an automobile equipped with an insulation resistance decrease detection device that detects a decrease in insulation resistance of an electrical system,
The control means is configured such that when the rotational speed of the motor is within a predetermined rotational speed range determined as a range in which a decrease in insulation resistance may be erroneously detected with respect to noise caused by the rotation of the motor, or the center shift When PWM control is being executed, it is means for prohibiting detection of a decrease in insulation resistance by the insulation resistance decrease detection device.
A car characterized by that.

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