JP2016080351A - Automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a relay which is not deposited from being deposited, when specifying an insulation deterioration portion of a high voltage system.SOLUTION: An off-command is output to a positive electrode side relay SMRB, a negative electrode side relay SMRG, and a precharge relay SMRP (S110, S130). Then, similarly to a case before the off-command is output to them, when insulation resistance to a vehicle body of a diagnosis object is deteriorated (S150, S152), a DC/DC converter is controlled so that charge (precharge) of a capacitor can be performed (S180). Then, when a voltage difference (Vb-VL) between battery voltage Vb of a battery and voltage VL of the capacitor is less than a threshold Vref (S170), an on-command is output to the positive electrode side relay SMRB (S190).SELECTED DRAWING: Figure 5

Description

  The present invention relates to an automobile.

  2. Description of the Related Art Conventionally, as this type of automobile, an automobile including a traveling motor, an inverter, a high voltage battery, positive and negative system main relays, and a detection device has been proposed (for example, a patent). Reference 1). Here, the inverter drives the motor. The system main relays on the positive electrode side and the negative electrode side are respectively provided on the positive electrode bus and the negative electrode bus connecting the high voltage battery and the inverter. The detection device is connected to the negative terminal of the high voltage battery, and detects the presence or absence of a decrease in the insulation resistance of the high voltage battery and the vehicle body of the high voltage system as a circuit electrically connected to the high voltage battery. In a vehicle configured in this way, when there is a request to stop the high voltage system, if there is a history of decrease in insulation resistance of the high voltage system and the inverter has failed, either the positive or negative system main relay One is turned off, and discharge control is performed to reduce the inverter applied voltage to a value of zero. When the insulation resistance decreases before and after the discharge control changes from “No” to “Yes”, the AC section (the part on the motor side of the inverter) is identified as the insulation resistance lowered part, and the insulation resistance decreases before and after the discharge control. If there is no change with the decrease of “Yes”, the DC part (the part on the high voltage battery side of the inverter) is specified as the insulation resistance decreasing part.

JP 2013-172542 A

  In such an automobile, when the insulation resistance drop by the detection device is “Yes” and the insulation resistance drop portion is identified, the system main relay on the positive electrode side and the negative electrode side is turned off and the system main on the positive electrode side or the negative electrode side is subsequently turned off. It is also considered that the insulation resistance lowering part is specified by turning on the relay and determining whether the decrease in insulation resistance by the detection device is “Yes”, “No”, “Yes”, or “Yes”. . In this case, the capacitor charge is consumed as heat by the discharge resistor connected in parallel to the capacitor between the time when the positive and negative system main relays are turned off and the time when the positive or negative system main relay is turned on. As a result, the voltage of the capacitor decreases, and the difference between the battery voltage and the capacitor voltage may increase. For this reason, for example, when the system main relay on the positive electrode side is turned on when the difference between the battery voltage and the capacitor voltage is large and the negative system main relay is welded, the positive and negative system systems There is a possibility that a large current flows through the main relay and the system main relay on the positive electrode side is also welded.

  The main object of the automobile of the present invention is to suppress the welding of a non-welded relay when specifying the insulation lowering portion of the high voltage system.

  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 includes a motor for traveling, an inverter for driving the motor, a high-voltage battery, a capacitor attached to a power line connecting the high-voltage battery and the inverter, and the capacitor A high-voltage system comprising: a discharge resistor connected in parallel; and a positive-side relay and a negative-side relay provided on the positive-side line and the negative-side line on the battery side from the capacitor and the discharge resistor of the power line; A low voltage battery, a DC / DC converter connected to the power line and the low voltage battery, and connected to the high voltage system to detect a decrease in insulation resistance with respect to a part or the whole vehicle body of the high voltage system Detecting a decrease in insulation resistance with respect to the vehicle body of the entire high-voltage system. An off command output process for outputting an off command to the positive relay and the negative relay, and an on command output process for outputting an on command to the positive relay or the negative relay after the off command output process. And a control means for specifying an insulation resistance lowering portion in which an insulation resistance with respect to the vehicle body is lowered with the execution of the vehicle, wherein the control means, after the execution of the off command output process, When a decrease in insulation resistance is detected by the detection device, the DC / DC converter is controlled so that the capacitor is charged, and the on-command output process is executed after the capacitor is charged.

  In the automobile of the present invention, when the detection device detects a decrease in insulation resistance with respect to the vehicle body of the entire high-voltage system, an off command output process for outputting an off command to the positive side relay and the negative side relay, and an off command output process An insulation resistance lowering portion in which the insulation resistance with respect to the vehicle body is lowered with the execution of an on command output process for outputting an on command to the positive side relay or the negative side relay later is specified. When the detection device detects a decrease in insulation resistance after the execution of the off command output process, the DC / DC converter is controlled so that the capacitor is charged, and the on command output process is performed after the capacitor is charged.

  Here, the part to be diagnosed by the detection device (the part to be diagnosed as to whether or not the insulation resistance is lowered) before execution of the off command output process, after execution of the off command output process, and after execution of the on command output process ) When the positive side relay and negative side relay are normal (when not welded), the whole high voltage system, the positive side relay and the negative side relay will be the detection device side, the whole high voltage system, and the positive side relay When at least one of the negative electrode side relay and the negative electrode side relay is welded, the entire high voltage system is obtained.

  Therefore, when the decrease in insulation resistance is detected by the detection device both before and after the execution of the off command output process, the positive side relay and the negative side relay are normal and the positive side relay and the negative side relay When the insulation resistance with respect to the vehicle body is reduced on the side opposite to the detection device, and when at least one of the positive side relay and the negative side relay is welded (the insulation resistance reduction part cannot be specified), Can be considered.

  By the way, when the connection between the battery side and the capacitor side is released by either or both of the positive electrode side line and the negative electrode side line due to the execution of the off command output process, the charge of the capacitor is consumed as heat by the discharge resistance. The capacitor voltage drops. For this reason, for example, when the negative side relay is welded and an ON command is output to the positive side relay when the voltage difference between the battery voltage and the capacitor voltage is large, the positive side relay and the negative side relay are greatly affected. There is a possibility that current flows and a positive-side relay that is not welded is also welded. On the other hand, in the automobile of the present invention, after the OFF command output process is executed, when the detection device detects a decrease in insulation resistance, the DC / DC converter is controlled so that the capacitor is charged, and the capacitor is charged. The on command output process is executed later. As a result, the ON command output process is executed after the voltage difference between the battery voltage and the capacitor voltage is reduced, so that a large current is prevented from flowing through the positive side relay and the negative side relay. It can suppress that the relay which is not welded among a relay and a negative electrode side relay welds. It should be noted that “after charging the capacitor” may be when the voltage difference between the battery voltage of the high-voltage battery and the voltage of the capacitor reaches a threshold value or less.

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 a flowchart which shows an example of the insulation diagnostic routine performed by HVECU70 of an Example. It is explanatory drawing which shows typically the relationship between the state of the positive electrode side relay SMRB at the time of performing the insulation diagnosis of a high voltage system, and whether the insulation resistance of a diagnostic object is falling.

  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 drop detecting device 90 and a simple model 95 of a system to which the insulation resistance drop 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.

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when performing insulation diagnosis of the high voltage system will be described. FIG. 5 is a flowchart illustrating an example of an insulation diagnosis routine executed by the HVECU 70 of the embodiment. This routine is executed, for example, when the ignition is turned off. At the start of execution of this routine, the positive side relay SMRB and the negative side relay SMRG are turned on, and the precharge relay SMRP is turned off. In other words, the object to be diagnosed by the insulation resistance lowering detection device 90 is the entire high voltage system.

  When the insulation diagnosis routine is executed, the HVECU 70 first uses the amplitude of the voltage waveform from the voltage sensor 94 of the insulation resistance lowering detection device 90 to reduce the insulation resistance of the diagnosis target, that is, the entire vehicle body of the high voltage system. It is determined whether or not (steps S100 and S102). And when it determines with the insulation resistance with respect to the vehicle body of the whole high voltage system having not fallen, this routine is complete | finished as it is. When this routine is finished, the system shifts to a system stop process.

  When it is determined that the insulation resistance with respect to the vehicle body of the entire high-voltage system has decreased, an off command is output to the negative side relay SMRG and the precharge relay SMRP (step S110), and a predetermined time T1 is awaited. (Step S120). The process of step S110 is a process of starting output of an off command for the negative relay SMRG (a process of switching from an on command to an off command), and outputs an off command to the precharge relay SMRP. It is a continuous process. Further, the predetermined time T1 is a time required for the positive-side relay SMRB to actually switch from on to off after the output of the off command to the positive-side relay SMRB from the HVECU 70 or a slightly longer time, for example, It can be 80 msec, 100 msec, 120 msec, or the like.

  Subsequently, an off command is output to the positive relay SMRB (step 130). This process is a process for starting output of an off command to the positive relay SMRB (switching from an on command to an off command). The object of diagnosis by the insulation resistance lowering detection device 90 is that when all of the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are normal (when not welded) by the processing of steps S110 and 130. When the entire high voltage system is switched to the battery unit and at least one of the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP is welded, the entire high voltage system remains.

  Then, it waits for completion of the confirmation of the amplitude of the voltage waveform from the voltage sensor 94 (steps S140 and S142). Here, the confirmation of the amplitude of the voltage waveform from the voltage sensor 94 is performed when the amplitude of the voltage waveform input from the voltage sensor 94 is stabilized after the process of step S130.

  When the confirmation of the amplitude of the voltage waveform from the voltage sensor 94 is completed, it is determined using the amplitude whether or not the insulation resistance with respect to the body to be diagnosed has decreased (steps S150 and S152). When it is determined that the insulation resistance for the vehicle body to be diagnosed has not decreased, all of the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are normally off, and the vehicle body of the battery unit It is determined that the insulation resistance against is not lowered.

  Then, an ON command is output to the positive relay SMRB (step S190). This process is a process for starting output of an on command to the positive relay SMRB (switching from an off command to an on command). Now, since it is considered that the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are normal, the process of step S190 switches the diagnosis target from the battery unit to the entire high voltage system.

  Then, it waits for completion of confirmation of the amplitude of the voltage waveform from the voltage sensor 94 (steps S200 and S202). In this case, confirmation of the amplitude of the voltage waveform from the voltage sensor 94 is performed when the amplitude of the voltage waveform input from the voltage sensor 94 is stabilized after the process of step S190. In addition, when it is determined in steps S100 and S102 that the insulation resistance with respect to the vehicle body of the entire high voltage system has decreased, and when it is determined in steps S150 and S152 that the insulation resistance with respect to the vehicle body of the battery unit has not decreased. Therefore, if the amplitude of the voltage waveform confirmed in steps S200 and S202 is used, it is determined that the insulation resistance with respect to the body to be diagnosed is reduced.

  When the confirmation of the amplitude of the voltage waveform from the voltage sensor 94 is completed, the part where the insulation resistance with respect to the vehicle body is reduced in the entire high voltage system is specified (step S210), and this routine is finished. Considering the case where the insulation resistance of the entire high-voltage system with respect to the vehicle body is reduced and the insulation resistance of the battery unit with respect to the vehicle body is not reduced, the positive side relay SMRB, the negative side relay SMRG, and the precharge relay It is determined that all of the SMRP is normal and that the insulation resistance of the inverter portion with respect to the vehicle body is reduced.

  When it is determined in steps S150 and S152 that the insulation resistance with respect to the body to be diagnosed has decreased, all of the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are normally off and Insulation resistance with respect to the vehicle body of the battery unit is lowered, or at least one of the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP is welded (insulation lowering portion cannot be specified), Judge.

  Then, the battery voltage Vb of the high voltage battery 50 and the voltage VL of the capacitor 57 are input (step S160). Here, the battery voltage Vb of the high voltage battery 50 is detected by the voltage sensor 51 and input from the battery ECU 52 by communication. Further, the voltage VL of the capacitor 57 is the one detected by the voltage sensor 58a and input from the motor ECU 40 by communication.

  When the battery voltage Vb of the high voltage battery 50 and the voltage VL of the capacitor 57 are thus input, the voltage difference (Vb−VL) between the input battery voltage Vb of the high voltage battery 50 and the voltage VL of the capacitor 57 is compared with the threshold value Vref. (Step S170). When the voltage difference (Vb−VL) is smaller than the threshold value Vref, an ON command is output to the positive side relay SMRB (step S190), and the processes after step S200 are executed. In this case, in step S210, as described above, all of the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are normal and the insulation resistance of the battery unit with respect to the vehicle body has decreased, or It is determined that at least one of the side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP is welded (the insulation lowering portion cannot be specified).

  Here, the threshold value Vref will be described. At the start of execution of this routine, since the positive relay SMRB and the negative relay SMRG are on, the voltage difference (Vb−VL) is approximately zero. However, if the battery unit and the inverter unit are cut off by either or both of the positive electrode side line and the negative electrode side line of the battery voltage system power line 54b by executing the processes of steps S110 to S130, the capacitors 57 and 58 are disconnected. Are consumed as heat by the discharge resistor 59, and the voltages VH and VL of the voltage sensors 57a and 58a decrease. When the voltage difference (Vb−VL) is large, if the negative relay SMRG is not welded, even if the positive relay SMRB is turned on, a large current does not flow through the positive relay SMRB. However, if the negative electrode side relay SMRG is welded, a large current flows through the positive electrode side relay SMRB and the negative electrode side relay SMRG when the positive electrode side relay SMRB is turned on, and not only the negative electrode side relay SMRG but also the positive electrode side relay SMRG. SMRB may also be welded. Considering this, the threshold value Vref is a lower limit value of a voltage difference that may cause the positive relay SMRB to be welded if the positive relay SMRB is turned on while the negative relay SMRG is welded. A slightly small value, for example, 50V, 70V, 100V or the like is used.

  When the voltage difference (Vb−VL) is greater than or equal to the threshold value Vref in step S170, the DC / DC converter 62 is controlled so that the capacitors 57 and 58 are charged (precharge) (step S180), and the process returns to step S160. In this way, the processes of steps S160 to S180 are repeatedly executed. When it is determined in step S170 that the voltage difference (Vb−VL) is less than the threshold value Vref, an ON command is output to the positive relay SMRB (step S190). Then, the processing after step S200 is executed. In this case, in step S210, as described above, all of the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are normal and the insulation resistance of the battery unit with respect to the vehicle body has decreased, or It is determined that at least one of the side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP is welded (the insulation lowering portion cannot be specified).

  As described above, after the voltage difference (Vb−VL) becomes less than the threshold value Vref, when the negative relay SMRG is welded by outputting an ON command to the positive relay SMRB, the positive relay SMRB It is possible to suppress the positive relay SMRB from being welded by being turned on. When the positive side relay SMRB is welded, normal relays (the negative side relay SMRG and the precharge relay SMRP) are not welded by the output of the ON command to the positive side relay SMRB in step S190. When the precharge relay SMRP is welded, the capacitor 57, until the voltages VH, VL of the capacitors 57, 58 are equal to the high voltage battery 50 by the output of the ON command to the positive side relay SMRB in step S190. 58 is charged, but is the same as when the capacitors 57 and 58 are precharged using the positive side relay SMRB and the precharging relay SMRP, so that normal relays (positive side relay SMRB and negative side relay SMRG) Does not weld.

  FIG. 6 is an explanatory diagram schematically showing a relationship between the state of the positive relay SMRB and whether or not the insulation resistance to be diagnosed is lowered when performing insulation diagnosis of the high voltage system. FIG. 6A shows the relationship when the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are all normal and the insulation resistance of the inverter portion with respect to the vehicle body is reduced. Further, FIG. 6B shows that the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP are all normal and the insulation resistance of the battery unit with respect to the vehicle body is reduced, or the positive side relay SMRB. , And at least one of the negative side relay SMRG and the precharge relay SMRP is welded (the insulation lowering portion cannot be specified). In the case of FIG. 6A, the insulation resistance to be diagnosed is lowered, normal, and lowered in accordance with ON / OFF / ON of the positive relay SMRB. In the case of FIG. 6B, the insulation resistance to be diagnosed is lowered regardless of whether the positive relay SMRB is on, off, or on. In this case, there is a possibility that the positive side relay SMRB is normal and the negative side relay SMRG is welded. Therefore, as described above, the capacitors 57 and 58 are charged by the DC / DC converter 62 and the voltage difference ( By outputting the ON command to the positive relay SMRB after (Vb−VL) becomes less than the threshold value Vref, it is possible to suppress the positive relay SMRB from being welded.

  According to the hybrid vehicle 20 of the embodiment described above, an off command is output to the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP, and thereafter an on command is output to the positive side relay SMRB, In each case, it is determined whether or not the insulation resistance with respect to the vehicle body to be diagnosed is lowered, thereby specifying the insulation lowered portion. Then, after outputting the off command to the positive side relay SMRB, the negative side relay SMRG, and the precharge relay SMRP (after starting the output of the off command), the diagnosis is performed in the same manner as before outputting the off command to them. When it is determined that the insulation resistance with respect to the target vehicle body is lowered, the DC / DC converter 62 is controlled so that the capacitors 57 and 58 are charged (precharge), and the battery voltage Vb of the high voltage battery 50 is When the voltage difference (Vb−VL) from the voltage VL of the capacitor 57 is less than the threshold value Vref, an ON command is output to the positive side relay SMRB. Thereby, when the negative relay SMRG is welded, it is possible to suppress the positive relay SMRB from being welded by turning on the positive relay SMRB.

  In the hybrid vehicle 20 of the embodiment, after the OFF command is output to the positive relay SMRB, the negative relay SMRG, and the precharge relay SMRP, the ON command is output to the positive relay SMRB. An on command may be output to the SMRG. In this case, after outputting the off command to the positive side relay SMRB, the negative side relay SMRG, and the precharging relay SMRP, the insulation resistance with respect to the vehicle body to be diagnosed is reduced as before the off command is output to them. If it is determined that the capacitor 57, 58 is charged (precharge), the DC / DC converter 62 is controlled so that the voltage difference between the battery voltage Vb of the high voltage battery 50 and the voltage VL of the capacitor 57 ( When Vb−VL) is less than the threshold value Vref2, an on command may be output to the negative relay SMRG. Here, the threshold value Vref2 is a lower limit value of a voltage difference that may cause the negative relay SMRG to be welded when the negative relay SMRG is turned on while the positive relay SMRB is welded, or a value slightly smaller than that. Etc. can be used. Thereby, when the positive electrode side relay SMRB is welded, it can be suppressed that the negative electrode side relay SMRG is also welded by turning on the negative electrode side relay SMRG.

  In the hybrid vehicle 20 of the embodiment, after outputting the off command to the positive side relay SMRB, the negative side relay SMRG, and the precharging relay SMRP, the insulation against the vehicle body to be diagnosed is performed in the same manner as before outputting the off command to these. When it is determined that the resistance has decreased, the DC / DC converter 62 is adjusted so that the voltage difference (Vb−VL) between the battery voltage Vb of the high voltage battery 50 and the voltage VL of the capacitor 57 is less than the threshold value Vref. Although controlled, the DC / DC converter 62 may be controlled such that the voltage difference (Vb−VH) between the battery voltage Vb of the high voltage battery 50 and the voltage VH of the capacitor 58 is less than the threshold value Vref. Good.

  In the hybrid vehicle 20 of the embodiment, after outputting an off command to the negative side relay SMRG and the precharge relay SMRP, after waiting for a predetermined time T1 to pass, the off command is output to the positive side relay SMRB. However, an off command may be output to the positive relay SMRB without waiting for the predetermined time T1 to elapse.

  In the hybrid vehicle 20 of the embodiment, after the off command is output to the negative side relay SMRG and the precharge relay SMRP, the off command is output to the positive side relay SMRB after waiting for a predetermined time T1. The ON command is output to the side relay SMRB and the insulation lowering portion is specified. However, when a predetermined time T1 has elapsed after the OFF command is output to the negative relay SMRG and the precharge relay SMRP, the capacitor 57 When the voltage VL is equal to or lower than a threshold VLref (for example, 5V, 10V, 15V, etc.), an off command may be output to the positive relay SMRB as the system stop process, and the insulation lowering portion may not be specified.

  In the hybrid vehicle 20 of the embodiment, the insulation diagnosis routine of FIG. 5 is executed when the ignition is turned off. In other cases, for example, when the shift lever 81 is operated to the parking position after traveling. It is good also as what is performed.

  In the hybrid vehicle 20 of the embodiment, the insulation resistance lowering detection device 90 is connected to the negative terminal of the high voltage battery 50, that is, the high voltage battery 50 side from the system main relay 56. It may be connected to the inverters 41 and 42 side.

  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 runs 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, the inverter 42, the high voltage battery 50, the capacitors 57 and 58, the positive side relay SMRB and the negative side relay SMRG correspond to the “high voltage system”, and the low voltage battery 60 is the “low voltage battery”. The DC / DC converter 62 corresponds to “DC / DC converter”, the insulation resistance reduction detecting device 90 corresponds to “detecting device”, and the HVECU 70 corresponds to “control means”.

  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 can be used in 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 motor for driving, an inverter for driving the motor, a high voltage battery, a capacitor attached to a power line connecting the high voltage battery and the inverter, and a discharge resistor connected in parallel to the capacitor A positive voltage side relay and a negative voltage side relay provided on the positive electrode side line and the negative electrode side line on the battery side from the capacitor and the discharge resistance of the power line, and a high voltage system,
A low voltage battery;
A DC / DC converter connected to the power line and the low voltage battery;
A detection device connected to the high voltage system for detecting a decrease in insulation resistance with respect to a part of or the whole vehicle body of the high voltage system;
An off command output process for outputting an off command to the positive side relay and the negative side relay when a decrease in insulation resistance with respect to the vehicle body of the entire high voltage system is detected by the detection device, and after the off command output process, An on-command output process for outputting an on-command to the positive-side relay or the negative-side relay, and a control means for specifying an insulation resistance lowering portion where an insulation resistance with respect to the vehicle body is lowered with the execution of,
A car equipped with
The control means controls the DC / DC converter so that the capacitor is charged when a decrease in insulation resistance is detected by the detection device after the execution of the off command output process, and after the capacitor is charged. Performing the on-command output process;
A car characterized by that.

Images