JP6973289B2 - Hybrid car - Google Patents

Description

The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle including an engine, first and second motors, a drive circuit, a power storage device, a boost converter, a system main relay, and a control device.

Conventionally, as a hybrid vehicle of this type, those including an engine, first and second motors, a drive circuit, a power storage device, a boost converter, and a system main relay have been proposed (for example, patent documents). 1). The first motor can crank the engine and can generate electricity by using the power from the engine. The second motor inputs and outputs power to the drive shaft connected to the axle. The drive circuit drives the first and second motors. The boost converter is connected to the low voltage power line on the power storage device side and the high voltage power line on the drive circuit side to boost the power of the low voltage power line and supply it to the high voltage power line. The system main relay connects and disconnects the power storage device to and from the low voltage power line by turning it on and off. In this hybrid vehicle, when the second motor is regeneratively controlled and an abnormality occurs in which the voltage between the terminals of the power storage device becomes an overvoltage, the boost converter is shut off and the system main relay is turned off. Then, when the engine is stopped, the evacuation running can be started by cranking the engine with the first motor and starting the engine.

JP-A-2017-165377

In the above-mentioned hybrid vehicle, generally, the system main relay is turned on, the power from the battery is boosted by the boost converter and supplied to the first motor, the engine is cranked by the first motor, and then the engine is started. , The control is performed to turn off the system main relay and start the retracting run. In this control, the drive circuit is stopped and the system main relay is put into a non-arc state in order to suppress the on-sticking of the system main relay after the engine is started and before the system main relay is turned off. At this time, since the first motor is rotated by the engine, a counter electromotive force is generated in the first motor, and the counter electromotive current may flow into the power storage device. From the viewpoint of protecting the power storage device, it is desirable to suppress the inflow of such counter electromotive current into the power storage device.

The main object of the hybrid vehicle of the present invention is to suppress the back electromotive current of the first motor from flowing into the power storage device.

The hybrid vehicle of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The hybrid vehicle of the present invention is
With the engine
A first motor that can crank the engine and generate electricity using the power from the engine.
A second motor that inputs and outputs power to the drive shaft connected to the axle,
The drive circuit that drives the first and second motors,
Power storage device and
A boost converter connected to the low-voltage power line on the power storage device side and the high-voltage power line on the drive circuit side to boost the voltage of the low-voltage power line and supply it to the high-voltage power line.
A system main relay that connects and disconnects the power storage device to and from the low-voltage power line by turning it on and off.
The system main relay is turned off, the required power is output from the engine, and the power generated by the first motor is consumed by the second motor by using a part of the power output from the engine. A control device that controls the engine, the drive circuit, the boost converter, and the system main relay so as to travel in the engine.
It is a hybrid car equipped with
The control device is
The engine and the drive circuit so that the system main relay is turned on, the engine is cranked by the first motor to start the engine, and then the system main relay is turned off to start the retracted run. To control the boost converter and the system main relay,
In addition,
When the driving of the first and second motors by the drive circuit is stopped after the engine is started with the system main relay turned on and before the system main relay is turned off, the high voltage is applied. The boost converter is controlled so that the voltage on the power line side becomes higher than the countercurrent voltage of the first motor.
The gist is that.

In the hybrid vehicle of the present invention, the engine and the drive circuit are started so that the system main relay is turned on, the engine is cranked by the first motor to start the engine, and then the system main relay is turned off to start the retracted running. And controls the boost converter and the system main relay. Then, after the engine is started with the system main relay turned on and before the system main relay is turned off, when the driving of the first and second motors by the drive circuit is stopped, the high voltage power line side The boost converter is controlled so that the voltage is higher than the countercurrent voltage of the first motor. When the engine is started, the first motor is taken to the engine and a counter electromotive force is generated in the first motor, but the boost converter is controlled so that the voltage on the high voltage power line side is higher than the counter electromotive voltage of the first motor. By doing so, it is possible to suppress the back electromotive force of the first motor from flowing into the power storage device.

In such a hybrid vehicle of the present invention, the control device is a case where the system is started, the driving is performed after the system main relay is turned on and the engine is started, and before the system main relay is turned off. When the drive of the first and second motors by the circuit is stopped, the boost converter may be controlled so that the voltage on the high voltage power line side becomes higher than the countercurrent voltage of the first motor.

Further, the hybrid vehicle of the present invention includes a power storage management device capable of communicating with the control device and managing the state of the power storage device, and the control device has an abnormality in communication with the power storage management device. When the system is started in this state, the system main relay is turned on, the engine is cranked by the first motor to start the engine, and then the system main relay is turned off to perform the retracting run. After controlling the engine, the drive circuit, the boost converter, and the system main relay so as to be started, and further starting the engine with the system main relay turned on, the system main relay is started. Before turning off, when the drive of the first and second motors by the drive circuit is stopped, the boost converter so that the voltage on the high voltage power line side becomes higher than the countercurrent voltage of the first motor. May be controlled. By doing so, it is possible to suppress the back electromotive current of the first motor from flowing into the power storage device when the system is started in a state where an abnormality occurs in the communication between the control device and the power storage management device.

It is a block diagram which shows the outline of the structure of the hybrid vehicle 20 as an Example of this invention. It is a block diagram which shows the outline of the structure of the electric drive system including the motor MG1 and MG2. It is a flowchart which shows an example of the predetermined time start processing routine executed by HVECU 70.

Next, an embodiment for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 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. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a buck-boost converter 55, a battery 50 as a power storage device, and a system main relay. A hybrid electronic control unit (hereinafter referred to as “HVECU”) 70 is provided.

The engine 22 is configured as an internal combustion engine that outputs power using gasoline, light oil, or the like as fuel. The engine 22 is operated and 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. .. Signals from various sensors necessary for controlling the operation of the engine 22, for example, a crank angle θcr from the crank position sensor 23 that detects the rotational position of the crankshaft 26 of the engine 22 and the like are input to the engine ECU 24 from the input port. Has been done. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via the output port. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr from the crank position sensor 23.

The planetary gear 30 is configured as a single pinion type planetary gear mechanism. A rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. A drive shaft 36 connected to the drive wheels 39a and 39b via a differential gear 38 is connected to the ring gear of the planetary gear 30. The crankshaft 26 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28.

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

The inverters 41 and 42 are used to drive the motors MG1 and MG2. As shown in FIG. 2, the inverter 41 is connected to the high voltage side power line 54a, and the six diodes D11 to six transistors T11 to T16 and the six diodes D11 to each of the six transistors T11 to T16 are connected in parallel. It has D16 and. 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 electrode side line and the negative electrode side line of the high voltage side power line 54a, respectively. Further, each of the three-phase coils (U phase, V phase, W phase) of the motor MG1 is connected to each of the connection points between the transistors paired with the transistors T11 to T16. Therefore, when a voltage is applied to the inverter 41, the electronic control unit for the motor (hereinafter referred to as “motor ECU”) 40 adjusts the ratio of the on-time of the paired transistors T11 to T16. A rotating magnetic field is formed in the three-phase coil, and the motor MG1 is rotationally driven. Like the inverter 41, the inverter 42 is connected to the high voltage side power line 54a and has six transistors T21 to T26 and six diodes D21 to D26. Then, when a 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 to form a rotating magnetic field in the three-phase coil, and the motor MG2 It is driven to rotate.

The buck-boost converter 55 is connected to the high voltage side power line 54a and the low voltage side power line 54b, and two transistors T31 and T32 and two transistors T31 and T32 connected in parallel to each of the two transistors T31 and T32. It has diodes D31 and D32 and a reactor L. The transistor T31 is connected to the positive electrode side line of the high voltage side power line 54a. The transistor T32 is connected to the transistor T31 and the negative electrode side line of the high voltage side power line 54a and the low voltage side power line 54b. The reactor L is connected to a connection point between the transistors T31 and T32 and a positive electrode side line of the low voltage side power line 54b. The buck-boost converter 55 boosts the power of the low voltage side power line 54b and supplies it to the high voltage side power line 54a by adjusting the ratio of the on-time of the transistors T31 and T32 by the motor ECU 40, or high voltage. The electric power of the side electric power line 54a is stepped down and supplied to the low voltage side electric power line 54b. A smoothing capacitor 57 is attached to the positive electrode side line and the negative electrode side line of the high voltage side power line 54a, and the smoothing capacitor 57 is attached to the positive electrode side line and the negative electrode side line of the low voltage side power line 54b. A capacitor 58 is attached.

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, signals from various sensors necessary for driving and controlling the motors MG1 and MG2 and the buck-boost converter 55 are input to the motor ECU 40 via the input port. The signal input to the motor ECU 40 flows, for example, to the rotation positions θm1 and θm2 from the rotation position detection sensors 43 and 44 that detect the rotation position of the rotors of the motors MG1 and MG2, and to each phase of the motors MG1 and MG2. The phase currents Iu1, Iv1, Iu2, Iv2 from the current sensors 45u, 45v, 46u, 46v that detect the current can be mentioned. Further, from the voltage (high voltage side voltage) VH of the capacitor 57 (high voltage side power line 54a) from the voltage sensor 57a attached between the terminals of the capacitor 57, or from the voltage sensor 58a attached between the terminals of the capacitor 58. The voltage (low voltage side voltage) VL of the capacitor 58 (low voltage side power line 54b) of the above can also be mentioned. From the motor ECU 40, various control signals for driving and controlling the motors MG1 and MG2 and the buck-boost converter 55 are output via the output port. Examples of the signal output from the motor ECU 40 include a switching control signal for the transistors T11 to T16 and T21 to T26 of the inverters 41 and 42 and a switching control signal for the transistors T31 and T32 of the buck-boost converter 55. .. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 has an electric angle θe1, θe2 and an angular velocity ωm1, ωm2, a rotation number Nm1, Nm2 of the motors MG1 and MG2 based on the rotation positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotation position detection sensors 43 and 44. Is being calculated.

The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and is connected to a low voltage side power line 54b. The battery 50 is managed by a battery electronic control unit (hereinafter, referred to as “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. .. Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input port. The signals input to the battery ECU 52 include, for example, the voltage Vb of the battery 50 from the voltage sensor 51a attached between the terminals of the battery 50 and the battery 50 from the current sensor 51b attached to the output terminal of the battery 50. Examples include the current Ib and the temperature Tb of the battery 50 from the temperature sensor 51c attached to the battery 50. The battery ECU 52 is connected to the HVECU 70 via a communication port. The battery ECU 52 calculates the storage ratio SOC based on the integrated value of the current Ib of the battery 50 from the current sensor 51b. The storage ratio SOC is the ratio of the capacity of electric power that can be discharged from the battery 50 to the total capacity of the battery 50. Further, the battery ECU 52 also calculates the output limit Wout and the input limit Win of the battery 50 based on the temperature Tb of the battery 50 from the temperature sensor 51c and the storage ratio SOC. The output limit Wout is the maximum allowable power (positive value power) that may be discharged from the battery 50. The input limit Win is the maximum allowable power (negative value power) at which the battery 50 may be charged.

The system main relay 56 is provided on the battery 50 side of the capacitor 58 in the low voltage side power line 54b. The system main relay 56 is controlled on and off by the HVECU 70 to connect and disconnect the battery 50 and the buck-boost converter 55 side.

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.

Signals from various sensors are input to the HVECU 70 via the input port. Examples of the signal input to the HVECU 70 include an ignition signal from the ignition switch 80 and a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81. Further, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed sensor 88. The vehicle speed V can also be mentioned. The shift position SP includes a parking position (P position), a reverse position (R position), a neutral position (N position), a forward position (D position), and the like.

From the HVECU 70, various control signals such as a drive signal to the system main relay 56 are output via the 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 a communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

The hybrid vehicle 20 of the embodiment configured in this way travels in any one of a plurality of driving modes including a hybrid traveling (HV traveling) mode and an electric traveling (EV traveling) mode. Here, the HV traveling mode is a mode in which the engine 22 is operated while traveling by using the power from the engine 22 and the power from the motors MG1 and MG2. The EV traveling mode is a mode in which the engine 22 is driven by power from the motor MG2 without being operated.

In the HV driving mode, the HVECU 70 first obtains the required torque (which should be output to the drive shaft 36) required for driving based on the accelerator opening Acc from the accelerator pedal position sensor 84 and the vehicle speed V from the vehicle speed sensor 88. Set Tr *. Subsequently, the required torque Tr * is multiplied by the rotation speed Np of the drive shaft 36 to calculate the traveling power Pdrv * required for traveling. Here, as the rotation speed Np of the drive shaft 36, the rotation speed Nm2 of the motor MG2, the rotation speed obtained by multiplying the vehicle speed V by the conversion coefficient, or the like can be used. Then, the required charge / discharge required power Pb * of the battery 50 (a positive value when discharging from the battery 50) is subtracted from the traveling power Pdrv * to calculate the required power Pe * required for the vehicle. Next, the engine so that 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 input from the battery ECU 52. The target rotation speed Ne * and the target torque Te * of 22 and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are set. Then, the target rotation speed Ne * and the target torque Te * of the engine 22 are transmitted to the engine ECU 24, and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are transmitted to the motor ECU 40. When the engine ECU 24 receives the target rotation speed Ne * and the target torque Te * of the engine 22, the intake air of the engine 22 is operated so that the engine 22 is operated based on the received target rotation speed Ne * and the target torque Te *. It performs quantity control, fuel injection control, ignition control, opening / closing timing control, etc. When the motor ECU 40 receives the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2, the transistors (switching elements) T11 to the inverters 41 and 42 are driven by the torque commands Tm1 * and Tm2 * so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. Switching control of T16, T21 to T26 is performed. The motor ECU 40 drives the motors MG1 and MG2 based on the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 and the rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 together with the switching control of the inverters 41 and 42. The required target voltage VH * is set, the target current IL * of the reactor L required for the voltage VH of the high voltage side power line 54a to become the target voltage VH * is set, and the current IL flowing through the reactor L is the target. Switching control of the transistors T31 and T32 of the buck-boost converter 55 is performed so that the current IL * is obtained. In this HV driving mode, when the required power Pe * reaches the stop threshold value Pstop or less, it is determined that the stopping condition of the engine 22 is satisfied, the operation of the engine 22 is stopped, and the vehicle shifts to the EV driving mode. ..

In the EV driving mode, the HVECU 70 first sets the required torque Tr * as in the HV driving mode. Subsequently, a value 0 is set in the torque command Tm1 * of the motor MG1. Then, 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 input / output limit Win and Wout of the battery 50 input from the battery ECU 52. Then, the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are transmitted to the motor ECU 40. The motor ECU 40 controls switching of the transistors (switching elements) T11 to T16 and T21 to T26 of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. Similar to the HV drive mode, the motor ECU 40 sets the target current IL * of the reactor L required for the voltage VH of the high voltage side power line 54a to become the target voltage VH * together with the switching control of the inverters 41 and 42. , Switching control of the transistors T31 and T32 of the buck-boost converter 55 is performed so that the current IL flowing through the reactor L becomes the target current IL *. In this EV driving mode, it is determined that the starting condition of the engine 22 is satisfied when the required power Pe * calculated in the same manner as in the HV driving mode reaches the starting threshold Pstart or more, which is larger than the stopping threshold Pstop. The engine 22 is started to shift to the HV driving mode.

In the hybrid vehicle 20 of the embodiment, when an abnormality occurs in the communication between the HVECU 70 and the battery ECU 52, the HVECU 70 cannot recognize the state of the battery 50 such as the input / output restriction Win and Wout of the battery 50, and appropriate control is performed. Cannot be executed. Therefore, the engine 22, the inverters 41, 42, the buck-boost converter 55, and the system main relay 56 are controlled so as to run in the batteryless running mode (evacuation running mode). In the batteryless driving mode, the driving power Pdrv * required for driving is output from the engine 22 with the system main relay 56 turned off, and the electric power generated by the motor MG1 is generated by using a part of the power output from the engine 22. This is a mode in which the vehicle travels while being consumed by the motor MG2.

Next, the operation of the hybrid vehicle 20 of the embodiment configured in this way, particularly the operation when the system is started in a state where an abnormality occurs in the communication between the HVECU 70 and the battery ECU 52 will be described. FIG. 3 is a flowchart showing an example of a predetermined time start processing routine executed by the HVECU 70. This routine is executed when a system start instruction is given in a state where an abnormality has occurred in communication between the HVECU 70 and the battery ECU 52. Examples of the abnormality in the communication between the HVECU 70 and the battery ECU 52 include an abnormality in which the communication between the HVECU 70 and the battery ECU 52 is interrupted. Further, the time when the system start instruction is given may be the time when the ignition signal from the ignition switch 80 is turned on. It is assumed that the hybrid vehicle 20 is parked in a state where the shift position SP is operated to the P position, the system main relay 56 is off, and the system is stopped before the execution of this routine. Therefore, the engine 22 is not operated, and the inverters 41, 42 and the buck-boost converter 55 are gate-blocked (gates of all transistors are turned off). Then, during the execution of this routine, the inverter 42 is gate-closed (the gates of the transistors T21 to T26 are turned off), and the driving of the motor MG2 is stopped.

When this routine is executed, the CPU (not shown) of the HVECU 70 outputs an ON drive signal to the system main relay 56 so that the system main relay 56 is turned on (step S100). As a result, the system main relay 56 is turned on, and the battery 50 and the low voltage side power line 54b are connected.

Subsequently, the motor MG1 cranks the engine 22 to execute start control for starting the engine 22, and also performs maximum boost control of the buck-boost converter 55 (step S110).

The start control of the engine 22 is performed as follows. A cranking torque Tcr is set in the torque command Tm1 * of the motor MG1, and the set torque command Tm1 * is transmitted to the motor ECU 40. The cranking torque Tcr is predetermined as a torque for rapidly increasing the rotation speed Ne of the engine 22. Upon receiving the torque command Tm1 *, the motor ECU 40 switches and controls the transistors T11 to T16 so that the torque corresponding to the torque command Tm1 * is output from the motor MG1. As a result, the engine 22 is cranked by the cranking torque Tcr from the motor MG1, and the rotation speed Ne of the engine 22 is increased. Then, when the rotation speed Ne of the engine 22 reaches the threshold value Nst or more, an operation start command is transmitted to the engine ECU 24. As the threshold value Nst, 600 rpm, 700 rpm, 800 rpm, or the like is used. Upon receiving the operation start command, the engine ECU 24 starts the control necessary for the operation of the engine 22, such as the fuel injection control and the ignition control of the engine 22. At this time, the output of the cranking torque Tcr from the motor MG1 exerts a torque on the drive shaft 36 via the planetary gear 30, but the drive wheels 39a and 39b are locked by a parking lock mechanism (not shown), so that the vehicle starts to move. There is no such thing. After starting the engine 22 in this way, the operation control of the engine 22 such as fuel injection control and ignition control is performed so that the engine 22 is autonomously operated at an autonomous rotation speed (600 rpm, 700 rpm, 800 rpm, etc.).

The maximum boost control of the buck-boost converter 55 is performed as follows. The maximum voltage VHmax predetermined as the maximum value of the voltage allowed in the high voltage side power line 54a is set to the target voltage VH * of the high voltage side power line 54a, and the target voltage VH * is transmitted to the motor ECU 40. Upon receiving the target voltage VH *, the motor ECU 40 switches and controls the transistors T31 and T32 of the buck-boost converter 55 so that the high voltage side voltage VH becomes the target voltage VH *. As will be described later, the maximum voltage VHmax is set as a value higher than the counter electromotive voltage generated in the motor MG1 when the engine 22 is started and the motor MG1 is rotated.

When the engine 22 is started, the inverter 41 is shut off (the gates of the transistors T11 to T16 are turned off) while the maximum boost control of the buck-boost converter 55 is continued (step S120). The gate cutoff of the inverter 41 is performed by transmitting a gate cutoff command of the inverter 41 to the motor ECU 40, and the motor ECU 40 receiving the gate cutoff command turns off the gates of the transistors T11 to T16 of the inverter 41. When the gate of the inverter 41 is shut off while the engine 22 is started, the motor MG1 is taken to the engine 22 and a counter electromotive force is generated in the motor MG1. Then, when the countercurrent voltage of the motor MG1 becomes higher than the voltage of the high voltage side power line 54a, a current flows from the motor MG1 to the battery 50 via the diodes D11 to D16. Now, since we are considering a case where an abnormality has occurred in the communication between the HVECU 70 and the battery ECU 52, the HVECU 70 cannot recognize the current actually flowing into the battery 50. In the embodiment, the voltage of the high voltage side power line 54a can be made higher than the countercurrent voltage of the motor MG1 by shutting off the gate of the inverter 41 while continuing the maximum boost control of the buck-boost converter 55, from the motor MG1. It is possible to suppress the flow of current into the battery 50. As a result, the battery 50 can be protected when an abnormality occurs in the communication between the HVE ECU 70 and the battery ECU 52.

When the inverter 41 is cut off at the gate in this way, the buck-boost converter 55 is shut off (the gates of the transistors T31 and T32 are turned off) and the buck-boost converter 55 is stopped (step S130). To shut off the gate of the buck-boost converter 55, a gate shut-off command of the buck-boost converter 55 is transmitted to the motor ECU 40, and the motor ECU 40 that receives the gate cut-off command turns off the gates of the transistors T31 and 32 of the buck-boost converter 55. It will be done.

Then, the system main relay 56 is turned off (step S140), the vehicle is ready-on (runnable state) (step S150), and this routine is terminated. In this way, the system main relay 56 is turned off with the inverters 41 and 42 and the buck-boost converter 55 cut off at the gate, that is, with the system main relay 56 in a non-arc state (a state in which no current is flowing through the system main relay 56). Therefore, it is possible to suppress the occurrence of an abnormality due to the system main relay 56 being stuck on.

After finishing this routine, when the shift position SP is operated to a running position such as a reverse position (R position) or a forward position (D position) to start running, the batteryless running mode (evacuation running mode) is used. ). As a result, even if an abnormality occurs in the communication between the HVECU 70 and the battery ECU 52, the vehicle can travel while protecting the battery 50.

According to the hybrid vehicle 20 of the embodiment described above, the inverters 41 and 42 are cut off from the gate after the engine 22 is started with the system main relay 56 turned on and before the system main relay 56 is turned off. When the driving of the motors MG1 and MG2 by 41 and 42 is stopped, the buck-boost converter 55 is controlled to boost the voltage to be higher than the countercurrent voltage of the motor MG1 so that the voltage of the high voltage side power line 54a is higher than that of the motor MG1. It is possible to suppress the back-up current of MG1 from flowing into the battery 50.

In the hybrid vehicle 20 of the embodiment, the voltage of the high voltage side power line 54a is made higher than the counter electromotive voltage of the motor MG1 by controlling the step-up / down converter 55 to boost the voltage at the maximum. However, since the voltage of the high voltage side power line 54a may be higher than the countercurrent voltage of the motor MG1, for example, the voltage of the high voltage side power line 54a according to the rotation speed Nm1 of the motor MG1 and the rotation speed Ne of the engine 22. May be controlled so that the buck-boost converter 55 is higher than the countercurrent voltage of the motor MG1.

In the hybrid vehicle 20 of the embodiment, when the system start instruction is given in a state where the communication between the HVECU 70 and the battery ECU 52 is abnormal, after the HVECU 70 and the system main relay 56 are turned on and the engine 22 is started. Before turning off the system main relay 56, the inverters 41 and 42 are shut off at the gate to control the buck-boost converter 55 to the maximum boost. However, regardless of the state of communication between the HVECU 70 and the battery ECU 52 and whether or not the system start instruction is given, the system main relay 56 is turned off even after the system main relay 56 is turned on and the engine 22 is started. If it is before, the inverters 41 and 42 may be shut off at the gate to control the buck-boost converter 55 to the maximum boost.

In the hybrid vehicle 20 of the embodiment, the battery 50 is provided as the power storage device, but a capacitor may be provided instead of the battery 50.

In the hybrid vehicle 20 of the embodiment, the planetary gear 30 connected to the engine 22, the motor MG1, and the drive shaft 36 connected to the axle, the motor MG2 that inputs and outputs electric power to the drive shaft 36, and the motors MG1 and MG2 are driven. Inverters 41 and 42, a buck-boost converter 55 that boosts the power of the battery 50 and supplies it to the inverters 41 and 42, and a system attached to a low-voltage side power line 54b between the battery 50 and the buck-boost converter 55. It is configured to include a main relay 56. However, the engine, the first motor that can crank the engine and generate power using the power from the engine, and the first motor that can crank the engine and generate power using the power from the engine. A second motor that can input and output power to the drive shaft, a drive circuit that drives the first and second motors, a power storage device, and a boost that boosts the power from the power storage device and supplies it to the first and second motors. Any configuration may be used as long as it includes a converter and a system main relay attached to a power line between the power storage device and the boost converter. For example, it may be configured as a so-called series hybrid vehicle.

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 will be described. In the embodiment, the engine 22 corresponds to the "engine", the motor MG1 corresponds to the "first motor", the motor MG2 corresponds to the "second motor", and the inverters 41 and 42 correspond to the "drive circuit". The battery 50 corresponds to a "power storage device", the buck-boost converter 55 corresponds to a "boost converter", the system main relay 56 corresponds to a "system main relay", and the engine ECU 24, the motor ECU 50, and the HVECU 70 are "controlled". Corresponds to "device".

As for the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problems of the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these examples, and the present invention is not limited to these embodiments, and various embodiments are used without departing from the gist of the present invention. Of course it can be done.

The present invention can be used in the manufacturing industry of hybrid vehicles and the like.

20 hybrid vehicle, 22 engine, 23 crank position sensor, 24 electronic control unit for engine (engine ECU), 26 crank shaft, 28 damper, 30 planetary gear, 36 drive shaft, 38 differential gear, 39a, 39b drive wheel, 40 motor Electronic control unit (motor ECU), 41,42 inverter, 43,44 rotation position detection sensor, 45u, 45v, 46u, 46v current sensor, 50 battery, 51a, 57a, 58a voltage sensor, 51b current sensor, 51c temperature sensor, 52 Electronic control unit for battery (battery ECU), 54a high voltage side power line, 54b low voltage side power line, 55 buck-boost converter, 56 system main relay, 57,58 capacitor, 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, D11-D16, D21-D26, D31, D32 diode, L reactor, MG1, MG2 motor, T11 to T16, T21 to T26, T31, T32 transistors.

Claims (1)

With the engine
A first motor that can crank the engine and generate electricity using the power from the engine.
A second motor that inputs and outputs power to the drive shaft connected to the axle,
The drive circuit that drives the first and second motors,
Power storage device and
A boost converter connected to the low-voltage power line on the power storage device side and the high-voltage power line on the drive circuit side to boost the voltage of the low-voltage power line and supply it to the high-voltage power line.
A system main relay that connects and disconnects the power storage device to and from the low-voltage power line by turning it on and off.
The system main relay is turned off, the required power required for driving is output from the engine, and the power generated by the first motor is consumed by the second motor by using a part of the power output from the engine. A control device that controls the engine, the drive circuit, the boost converter, and the system main relay so as to travel while traveling in a retracted manner.
It is a hybrid car equipped with
The control device is
The engine and the drive circuit so that the system main relay is turned on, the engine is cranked by the first motor to start the engine, and then the system main relay is turned off to start the retracted run. To control the boost converter and the system main relay,
In addition,
When the driving of the first and second motors by the drive circuit is stopped after the engine is started with the system main relay turned on and before the system main relay is turned off, the high voltage is applied. The boost converter is controlled so that the voltage on the power line side becomes higher than the countercurrent voltage of the first motor.
Hybrid car.

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