WO2018097170A1

WO2018097170A1 - Vehicle control apparatus, vehicle control method, and recording medium having vehicle control program recorded thereon

Info

Publication number: WO2018097170A1
Application number: PCT/JP2017/041985
Authority: WO
Inventors: 征輝西山; 宇鋒寿
Original assignee: 株式会社デンソー
Priority date: 2016-11-22
Filing date: 2017-11-22
Publication date: 2018-05-31
Also published as: CN109996712A; JP6597567B2; JP2018083486A; CN109996712B

Abstract

This vehicle control apparatus (50) is applicable to a vehicle (901, 902) that is provided with: an engine (70) and a motor-generator (60) which serve as power sources; and a main battery (20) which can transfer power to and from the motor-generator through an inverter (40). This vehicle control apparatus controls the operation of the engine and the motor-generator, and is capable of controlling the power transmission between the engine and the motor-generator. When abnormalities in the main battery are detected, the vehicle control apparatus interrupts a power relay (21) disposed between the main battery and the inverter and stops the power running operation of the motor-generator. Then the vehicle control apparatus eliminates at least one of the factors responsible for the increase in motor-generator rotational speed caused by the operation of the vehicle and suppresses the rotation of the motor-generator, while maintaining vehicle travel using the engine.

Description

Vehicle control device, vehicle control method, and recording medium storing vehicle control program

This disclosure relates to a vehicle control technique for controlling a vehicle.

Conventionally, the following techniques are known in a hybrid vehicle including an engine and a motor generator. Specifically, the speed is changed when the main engine battery is abnormal, and the motor generator is regeneratively generated while the vehicle is driven by the engine. The voltage generated at this time is controlled. Thereby, the power to the auxiliary battery is stably supplied.
For example, Patent Document 1 describes the following hybrid vehicle control device. The hybrid vehicle described in Patent Document 1 is a dual clutch vehicle including an odd-numbered first clutch and an even-numbered second clutch. In such a vehicle, the control device downshifts to the lowest gear position when the main engine battery is abnormal.

Japanese Patent No. 5855603

In the technique of Patent Document 1, the rotation of the motor generator increases due to a downshift or the like during high-speed traveling. In this case, in the technique described in Patent Document 1, there is a possibility that an overvoltage is applied to the inverter due to an increase in regenerative power. As a result, the elements constituting the inverter may be damaged.
The present disclosure provides a vehicle control technology that protects an inverter from overvoltage by suppressing rotation of a motor generator while maintaining engine running when a main engine power supply is abnormal.

A vehicle control device according to an aspect of the technology of the present disclosure includes a main power source (20) that can exchange power with a motor generator via an engine (70) and a motor generator (60) that are power sources, and an inverter (40). It is applied to a vehicle (901, 902) provided with The vehicle control device controls operations of the engine and the motor generator. The vehicle control device controls at least one of power transmission between the engine and the motor generator and power transmission between the motor generator and the axle (96).

This vehicle control device shuts off the power running operation of the motor generator by shutting off the power relay (21) provided between the main power source and the inverter when an abnormality of the main power source is detected. The vehicle control device controls the rotation of the motor generator while maintaining vehicle travel by the engine. That is, the vehicle control device executes a “motor generator rotation suppression process” (hereinafter “MG rotation suppression process”). In the MG rotation suppression process, the vehicle control device eliminates at least one of the factors that increase the rotation speed of the motor generator (hereinafter referred to as “MG rotation speed”) due to the operation of the vehicle, and suppresses the rotation of the motor generator. .

Specifically, the vehicle control device suppresses rotation of the engine that is directly transmitted to the motor generator or indirectly transmitted as the vehicle travels in the MG rotation suppression process. Alternatively, the vehicle control device directly suppresses the rotation of the motor generator in the MG rotation suppression process.
The MG rotation suppression processing includes, for example, prohibition of traction control function off, manual transmission mode operation prohibition, blipping operation prohibition during deceleration, and downshift operation prohibition during high-speed driving. In the vehicle control device, the operation of the above function is prohibited in the MG rotation suppression process. As a result, the vehicle control device eliminates the factor that increases the MG rotation speed due to the operation of the vehicle.

As described above, the vehicle control device of the present disclosure maintains engine running while stopping the power running operation of the motor generator when the main engine battery is abnormal. Therefore, in the technology of the present disclosure, retreat travel (limp home) is possible when the main battery is abnormal.
In addition, the vehicle control device of the present disclosure executes the above-described MG rotation suppression process. Thus, the vehicle control device avoids an increase in the MG rotation speed due to the rotation of the engine or axle being transmitted to the motor generator. As a result, the technology of the present disclosure can protect the elements of the inverter from an overvoltage applied to the inverter by regenerative power generation.

In addition, the inverter control unit of the vehicle control device of the present disclosure executes voltage control when a predetermined execution condition is satisfied for the MG rotation speed and the capacitor voltage as the inverter control mode. Thereby, in the technique of this indication, desired electric power can be supplied to an auxiliary machine battery from an inverter, for example. Therefore, with the technology of the present disclosure, functions such as a starter and an electric power steering device can be ensured while the vehicle is running away. On the other hand, the inverter control unit executes the gate cutoff when the execution condition of the voltage control is not satisfied.

1 is a schematic configuration diagram of a vehicle to which a vehicle control device of a first embodiment is applied. It is a block diagram of the control system in the vehicle of FIG. It is a main flowchart of a main machine battery abnormality process. It is a subflowchart of the MG rotation suppression process of FIG. It is a characteristic view of MG rotation speed in each of voltage control and gate interruption | blocking, and a capacitor voltage. It is a figure which shows switching with voltage control and gate interruption | blocking by the change of MG rotation speed. It is a time chart which shows the 1st operation example at the time of main machine battery abnormality. It is a time chart which shows the 2nd operation example at the time of main machine battery abnormality. It is a schematic block diagram of the axle split type vehicle to which the vehicle control apparatus of 2nd Embodiment is applied. It is a figure which shows the structural example which implement | achieves MG rotation suppression in the vehicle of an axle split system.

Hereinafter, an embodiment of a vehicle control device according to the technology of the present disclosure will be described with reference to the drawings. In the embodiments, substantially the same components are denoted by the same reference numerals, and the description thereof is omitted.
The vehicle control device according to one aspect of the technology of the present disclosure is applied to a hybrid vehicle including an engine and a motor generator (hereinafter “MG”) as power sources. The first embodiment is applied to a normal hybrid vehicle in which the engine and the MG cooperate to drive the same drive wheel. The second embodiment is applied to an axle split type vehicle in which an engine and an MG drive different drive wheels.

(First embodiment)
A first embodiment of the technology of the present disclosure will be described with reference to FIGS. 1 to 8.
As shown in FIG. 1, the vehicle control system 10 is applied to a vehicle 901. The vehicle control system 10 includes an engine 70, an MG 60, a main engine battery 20, an inverter 40,

power transmission clutches

81 and 82, a transmission 84, a vehicle control device 50, and the like.
The engine 70 converts thermal energy generated by burning fuel into rotational driving force.
The MG 60 performs a power running operation and a regenerative operation. In the power running operation, electric power supplied from the main battery 20 is consumed to generate torque. In the regenerative operation, power generated by torque transmitted from the engine 70 or the drive shaft 94 is regenerated to the main battery 20. The MG 60 of this embodiment is a permanent magnet type synchronous three-phase AC motor generator.

The main battery 20 functions as a main power source. The main battery 20 is configured by a chargeable / dischargeable secondary battery such as a nickel metal hydride battery or a lithium ion battery. The positive electrode of the main battery 20 is connected to the high potential line P, and the negative electrode of the main battery 20 is connected to the low potential line N.
The main battery 20 may be referred to as a “high voltage battery”, and an auxiliary battery 32 described later may be referred to as a “low voltage battery”. As the main power source, a power storage device such as an electric double layer capacitor may be used instead of the battery.

Between the main battery 20 and the inverter 40, a power supply relay 21 capable of interrupting the power path is provided. The power relay 21 corresponds to a system main relay. The power supply relay 21 includes a high potential side relay 22 provided on the high potential line P and a low potential side relay 23 provided on the low potential line N. The high potential side relay 22 and the low potential side relay 23 may be either a mechanical relay or a semiconductor relay.

The inverter 40 mutually converts the DC power on the main battery 20 side and the three-phase AC power on the MG 60 side. As shown in FIG. 2, the inverter 40 includes switching elements 41-46 of three-phase upper and lower arms. Specifically, the switching

elements

41, 42, and 43 are upper-arm switching elements of the U phase, the V phase, and the W phase, respectively. The switching

elements

44, 45, and 46 are switching elements of the lower arm of the U phase, the V phase, and the W phase, respectively. The switching elements 41 to 46 of the present embodiment are IGBTs (insulated gate bipolar transistors). Further, the switching elements 41-46 are accompanied by flywheel diodes that allow energization from the emitter side to the collector side. In other words, the switching element 41-46 is accompanied by a diode that allows energization from the low potential side to the high potential side.

A capacitor 25 for smoothing the input voltage is provided on the main battery 20 side of the inverter 40. The capacitor voltage Vc is a voltage across the capacitor 25. In other words, the capacitor voltage Vc is a potential difference between the high potential line P and the low potential line N. When the capacitor voltage Vc exceeds the withstand voltage upper limit value, elements such as the switching elements 41 to 46 of the inverter 40 may be damaged.
Therefore, in this embodiment, the capacitor voltage Vc may be monitored by, for example, a voltage sensor (not shown).

In the configuration example shown in FIG. 1, the DCDC converter 30 is connected to a path branched from the power path between the power supply relay 21 and the inverter 40. Note that the illustration of the DCDC converter 30 is omitted in FIG.
DCDC converter 30 steps down the high voltage power of main battery 20 and outputs the low voltage power. The auxiliary battery 32 is configured by a secondary battery such as a lead storage battery, for example. The auxiliary battery 32 is charged by the low voltage power output from the DCDC converter 30. The auxiliary battery 32 supplies low voltage power to various auxiliary loads 33 of the vehicle. The auxiliary machine load 33 includes devices having functions necessary for retreat travel, such as an engine starter, an electric power steering device, and a brake actuator.

The engine side clutch 81 is provided on the output shaft 71 of the engine 70. The engine side clutch 81 interrupts power transmission between the engine 70 and the MG 60.
The axle clutch 82 is provided on the drive shaft 94 on the output side of the MG 60. Axle side clutch 82 interrupts power transmission between MG 60 and axle 96. The transmission 84 can change the power transmitted to the drive shaft 94. The functions provided by the axle clutch 82 and the transmission 84 may be configured as, for example, a dual clutch transmission (DCT).
The driving force transmitted to the drive shaft 94 on the output side of the transmission 84 is transmitted to the axle 96 via the differential gear 95. As a result, the wheel 98 that is the driving wheel of the vehicle 901 rotates.

As shown in FIG. 2, the vehicle control device 50 includes a plurality of

ECUs

52, 54, 57, and 58 and a general ECU 51 that performs overall control thereof. The vehicle control device 50 controls the driving of the vehicle 901 in an integrated manner. The vehicle control device 50 communicates with the main engine battery 20, the power supply relay 21, the inverter 40, the MG 60, the engine 70, the

clutches

81 and 82, the transmission 84, etc., and inputs various information and outputs command signals. Each of the

ECUs

51, 52, 54, 57, 58 is configured mainly with a microcomputer or the like. The ECU can transmit and receive information via a communication network such as CAN. The ECU includes, for example, a CPU, a semiconductor memory such as a RAM and a ROM, an I / O, and the like. The semiconductor memory corresponds to a non-transitional tangible recording medium. In other words, the semiconductor memory is a computer-readable recording medium. For example, the ECU reads a program stored in the semiconductor memory, and the CPU executes a process defined by the program code. The ECU exchanges signals with external devices via the I / O. The ECU executes a predetermined process based on the input signal via the I / O, and outputs an execution result signal. Thereby, EUC provides a predetermined control function. Note that the function providing method is not limited to the above-described software method. As another providing method, for example, a hardware method using an electronic circuit such as an IC or a logic circuit may be used.

In FIG. 2, the vehicle control device 50 includes control units such as a general ECU 51, a battery ECU 52, an MG-ECU 54, an engine ECU 57, and a transmission ECU (T / M-ECU) 58. The vehicle on which vehicle control device 50 is mounted further includes an ECU (another ECU) other than the ECU shown in FIG. However, FIG. 2 illustrates only the configuration and signal input / output related to the main operation of the ECU in the present embodiment, and the configuration and signal input / output related to the operation of another ECU described above are described. Omitted.
Only the functions related to the main operation of this embodiment will be described below. Further, the function sharing by each ECU is not limited to the configuration shown below. The function sharing by each ECU may be a configuration in which any ECU can realize the same function as the entire vehicle control device 50.

The overall ECU 51 functions as a main control unit. The overall ECU 51 acquires information from the battery ECU 52, the MG-ECU 54, the engine ECU 57, and the transmission ECU 58. The overall ECU 51 acquires information (vehicle information) related to the vehicle 901 such as the accelerator opening, the shift position, and the vehicle speed from, for example, an accelerator sensor, a shift switch, a vehicle speed sensor, and the like (not shown). The overall ECU 51 controls the entire vehicle 901 based on the acquired vehicle information. Then, the overall ECU 51 transmits a control command signal to each of the MG-ECU 54, the engine ECU 57, and the transmission ECU 58. As a result, the overall ECU 51 instructs the

ECUs

54, 57, and 58 to execute processing.
Further, it is assumed that vehicle 901 can execute traction control (hereinafter referred to as “TRC”) that suppresses the rotation of a relatively high rotational speed of driving wheels 98. In such a vehicle 901, the general ECU 51 can prohibit the operation of “TRC function off” in which the driver arbitrarily stops the TRC function.

The battery ECU 52 functions as a power supply control unit. Battery ECU 52 acquires main unit battery information such as voltage, current, temperature, and SOC of main unit battery 20. The battery ECU 52 monitors the state of the main battery 20 so that the SOC of the main battery 20 is within a predetermined range. Battery ECU 52 detects an abnormality of main unit battery 20 based on the acquired main unit battery information. Then, the battery ECU 52 transmits the detection result to the general ECU 51.
The abnormality of the main battery 20 includes, for example, a voltage abnormality in which the voltage deviates from the normal range, an overcurrent abnormality in which the current exceeds the upper limit value, and an SOC abnormality in which the SOC deviates from the normal range. When the abnormality of the main battery 20 is detected, the battery ECU 52 shuts off the power supply relay 21 (ON → OFF). Thereby, main battery 20 and inverter 40 and MG 60 are disconnected.

The MG-ECU 54 functions as a motor generator control unit and an inverter control unit. The MG-ECU 54 transmits information on the actual MG torque Tm and the actual MG rotation speed Nm to the overall ECU 51. The MG-ECU 54 operates the operations of the switching elements 41-46 of the inverter 40 in accordance with the MG torque command Tm ^* and the MG rotational speed command Nm ^* transmitted from the overall ECU 51. Thereby, MG-ECU 54 controls driving of MG 60.
Here, the MG-ECU 54 acquires, for example, the motor current Im detected by the current sensor 64 and the electrical angle θ detected by the rotation angle sensor 65. Then, the MG-ECU 54 may calculate the MG torque Tm using the dq axis current obtained by coordinate conversion of the phase current. The MG-ECU 54 may acquire the MG torque Tm detected by a torque sensor (not shown). Further, the MG-ECU 54 may calculate the MG rotation speed Nm by differentiating the detected value of the electrical angle θ with respect to time. Further, the MG-ECU 54 may estimate the MG rotation speed Nm based on the estimated position in the position sensorless configuration.

The MG-ECU 54 performs PWM driving of the inverter 40 based on a voltage command value calculated by current feedback control or torque feedback control during normal control of the power running operation. Thereby, MG-ECU 54 causes inverter 40 to generate desired power, and supplies the generated power to MG 60.
In addition, the MG-ECU 54 performs “voltage control” or “gate cutoff” on the inverter 40 in the inverter control mode of the regenerative operation after the power supply relay 21 is shut off.

In the “voltage control” mode, the MG-ECU 54 operates the operations of the plurality of switching elements 41-46 of the inverter 40 to control the capacitor voltage Vc. In the “gate cutoff” mode, the MG-ECU 54 turns off all the plurality of switching elements 41-46 of the inverter 40. In the state where the gate is cut off, the current from the MG 60 side flows from the low potential side to the high potential side via the flywheel diode associated with the switching element 41-46.

The engine ECU 57 functions as an engine control unit. The engine ECU 57 transmits information on the actual engine torque Te and the actual engine speed Ne to the overall ECU 51. The engine ECU 57 operates the fuel injection valve injection amount, the injection timing, and the like in accordance with the engine torque command Te ^* transmitted from the general ECU 51. Thereby, engine ECU 57 controls the operation of engine 70.
The engine ECU 57 can inhibit the operation of “deceleration blipping” that increases the engine speed Ne when the vehicle 901 is decelerated, for example, in cooperation with an accelerator ECU or the like (not shown).

The transmission ECU 58 functions as a transmission control unit. The transmission ECU 58 transmits transmission information (T / M information) to the overall ECU 51. The transmission ECU 58 controls the operations of the

clutches

81 and 82 and the transmission 84 in accordance with the shift command transmitted from the overall ECU 51. In vehicle 901, transmission ECU 58 controls power transmission between engine 70 and MG 60 and power transmission between MG 60 and axle 96.

For example, the transmission ECU 58 instructs the

clutches

81 and 82 to switch between the engaged state, the semi-engaged state, and the released state. Further, the transmission ECU 58 instructs the transmission 84 to switch the shift position. The transmission ECU 58 prohibits the transmission 84 from performing a downshift. Furthermore, it is assumed that vehicle 901 can be switched between an automatic transmission mode (hereinafter “AT mode”) and a manual transmission mode (hereinafter “MT mode”). In the case of such a vehicle, the transmission ECU 58 can prohibit the operation in the MT mode.

By the way, after the abnormality of the main battery 20 is detected and the power supply relay 21 is cut off, the electric power generated by the MG 60 is not regenerated in the main battery 20 but is charged in the capacitor 25. Therefore, the capacitor voltage Vc increases. At this time, when the MG rotation speed Nm is high and the regenerative power generation amount is large, a load dump in which the capacitor voltage Vc becomes excessive occurs. The overvoltage due to the load dump may damage the switching elements 41-46, the capacitor 25, the elements of the DCDC converter 30, and the like.

Therefore, the vehicle control device 50 of the present embodiment shuts off the power relay 21 due to the abnormality of the main engine battery 20 and stops the power running operation of the MG 60. Then, the vehicle control device 50 controls the rotation of the MG 60 while maintaining the vehicle traveling by the engine 70 and enabling the retreat traveling. That is, the vehicle control device 50 executes “MG rotation suppression processing” for suppressing an increase in the MG rotation speed Nm. In this MG rotation suppression process, vehicle control device 50 suppresses the rotation of MG 60 by eliminating at least one of the factors that increase MG rotation speed Nm due to the operation of vehicle 901. Specifically, vehicle control device 50 prohibits the operation of at least one of the factors that increase MG rotation speed Nm due to the operation of vehicle 901. Then, vehicle control device 50 suppresses rotation of engine 70 that is directly transmitted to MG 60 or indirectly transmitted as vehicle 901 travels. Alternatively, the vehicle control device 50 directly suppresses the rotation of the MG 60.

Next, main battery abnormality processing by the vehicle control device 50 will be described with reference to FIGS. FIG. 3 shows a main flowchart of this process. FIG. 4 shows a sub-flowchart of this process. In the following description of the flowcharts, the symbol S represents “step”. In the present embodiment, an example is shown in which the CPU executes a vehicle control program stored in a recording medium such as a semiconductor memory and executed by the CPU in the vehicle control device 50, for example.
The vehicle control device 50 is redeioned (S1). Thereafter, the MG-ECU 54 normally controls the inverter 40 (S2). The MG-ECU 54 continues normal control until the battery ECU 52 detects abnormality of the main battery 20 (S3: NO).

When the abnormality of the main battery 20 is detected by the battery ECU 52 (S3: YES), the vehicle control device 50 compares the MG torque Tm at that time with the threshold value Tmth (S4). Then, the vehicle control device 50 determines whether the overall operation state of the MG 60 is a power running operation or a regenerative operation based on the comparison result. If the MG torque Tm is greater than the threshold value Tmth (S4: YES), the overall ECU 51 determines that the operation state of the MG 60 is a power running operation, and proceeds to the process of S5. On the other hand, when the MG torque Tm is equal to or less than the threshold value Tmth (S4: NO), the overall ECU 51 determines that the operation state of the MG 60 is a regenerative operation, and proceeds to the process of S6.

When an abnormality of the main engine battery 20 is detected during the power running operation of the MG 60 (S3: YES, S4: YES), in the vehicle control device 50, the battery ECU 52 turns off the power supply relay 21 (S5). At this time, the capacitor voltage Vc decreases. Therefore, in the normal control of the inverter 40, a diagnosis signal of the voltage sensor is generated. However, in this process, the power supply relay 21 is intentionally turned off. Therefore, the diagnosis signal of the voltage sensor is unnecessary. Therefore, the vehicle control device 50 masks the diagnosis signal of the voltage sensor (S7). Thereafter, the MG-ECU 54 waits for reception of a voltage control command transmitted from the overall ECU 51 (S8: NO). When the MG-ECU 54 receives a voltage control command from the overall ECU 51 (S8: YES), the vehicle control device 50 executes an MG rotation suppression process (S10) and a gate cutoff process (S21) for the inverter 40. That is, the MG rotation suppression process is executed in accordance with an instruction from the overall ECU 51.

On the other hand, when an abnormality of the main battery 20 is detected during the regenerative operation of the MG 60 (S3: YES, S4: NO), in the vehicle control device 50, the battery ECU 52 turns off the power supply relay 21 (S6). At this time, the voltage of the inverter 40 is increased by the power generated by the MG 60. As a result, a load dump in which the capacitor voltage Vc becomes excessive occurs. In order to prevent damage to circuit elements due to overvoltage due to this load dump, it is necessary to immediately shut off the inverter 40. Therefore, the vehicle control device 50 immediately executes the MG rotation suppression process (S10) and the gate cutoff process (S21) while the battery ECU 52 turns off the power supply relay 21.

As shown in FIG. 4, the vehicle control device 50 executes the following processes (a), (b), and (c) in the MG rotation suppression process (S10) (S11). Specifically, the overall ECU 51 turns on the following operation prohibition flags (control flags).
(A) TRC function off operation prohibition flag: ON
(B) MT mode operation prohibition flag: ON
(C) Deceleration blipping operation prohibition flag: ON
Further, the transmission ECU 58 determines whether or not the vehicle speed is greater than a predetermined speed threshold (S12). If the vehicle speed is greater than the speed threshold value (S12: YES), the transmission ECU 58 executes a process of (d) “prohibition of downshift operation” (S13). On the other hand, when the vehicle speed is equal to or lower than the speed threshold (S12: NO), the transmission ECU 58 permits downshifting (S14).

The above-described processing is executed for the following purpose.
(A) TRC function OFF operation prohibition process In TRC, when a wheel has an extremely high rotational speed compared to other wheels, it is determined that the wheel is idling and control is performed so that rotation of the wheel is suppressed. To do. If this function is stopped, the rotation of the idle wheel is transmitted, and the MG rotation speed Nm may increase. Therefore, in the present embodiment, the overall ECU 51 prohibits the “TRC function off” operation, which can be an increase factor of the MG rotation speed Nm, based on the operation prohibition flag.
(B) MT Mode Operation Prohibition Process In the MT mode, the MG rotation speed Nm may increase due to the driver's manual operation beyond the range that the vehicle control device 50 can control. Therefore, in the present embodiment, the transmission ECU 58 prohibits the “MT mode” operation, which can be an increase factor of the MG rotation speed Nm, based on the operation prohibition flag.

(C) Processing prohibition processing of blipping at the time of deceleration It is assumed that at the time of the deceleration shift, the driver depresses the accelerator and performs the deceleration blipping to increase the engine speed Ne. In this case, the transmission of the engine rotation Ne may increase the MG rotation speed Nm. Thus, in the present embodiment, the engine ECU 57 prohibits the operation of “deceleration blipping” that can be an increase factor of the MG rotation speed Nm, regardless of the vehicle speed, based on the operation prohibition flag.
(D) Downshift prohibition processing during high speed traveling The vehicle 901 may travel faster than a preset speed threshold. During such high speed traveling, it is preferable to prohibit downshifting by the transmission 84 itself. Therefore, in the present embodiment, the transmission ECU 58 prohibits “downshift” for the transmission 84 based on the determination result of the vehicle speed. Thereby, in the vehicle control apparatus 50, the increase in the engine speed Ne accompanying a downshift and the increase in the MG speed Nm accompanying it can be prevented.
Thus, in the vehicle control device 50, in the MG rotation suppression process, the operation of at least one of the factors that increase the MG rotation speed Nm due to the operation of the vehicle 901 is prohibited. Thereby, the vehicle control device 50 eliminates at least one of the factors that increase the MG rotation speed Nm.

Returning to the description of FIG. S21 to S24 are processes relating to switching of inverter control.
In the vehicle control device 50, the MG-ECU 54 gates the inverter 40 (S21). That is, immediately after the power supply relay 21 is turned off (S5 or S6), the inverter 40 is once gate-cut.
Next, in the vehicle control device 50, the MG-ECU 54 determines whether or not a predetermined voltage control execution condition is met (S22). In this voltage control execution condition, the MG rotation speed Nm is within the range between the upper limit value and the lower limit value (within a predetermined rotation speed range), and the capacitor voltage Vc is within the range between the upper limit value and the lower limit value ( In the predetermined voltage range), it is determined that the condition is satisfied. Here, the upper limit value of the MG rotation speed Nm is expressed as NmH, and the lower limit value is expressed as NmL. The upper limit value of the capacitor voltage Vc is expressed as VcH, and the lower limit value is expressed as VcL. In this case, the MG-ECU 54 determines that the voltage control execution condition is satisfied when the expressions (1) and (2) are satisfied. That is, an affirmative determination is made in S22 (S22: YES).
NmL ≦ Nm ≦ NmH (1)
VcL ≦ Vc ≦ VcH (2)

When it is determined that the voltage control execution condition is not satisfied (S22: NO), the MG-ECU 54 continues to block the gate (S21).
When it is determined that the voltage control execution condition is satisfied (S22: YES), the MG-ECU 54 determines whether or not it is ready-off (S23). As a result, when it is determined that the vehicle is ready-off (S23: YES), the vehicle control device 50 ends the processing routine. On the other hand, when it determines with not being ready-off (S23: NO), the vehicle control apparatus 50 transfers to the process of S24.
The MG-ECU 54 drives the inverter 40 and executes voltage control (S24). Thereafter, the vehicle control device 50 repeatedly determines whether or not the voltage control execution condition is satisfied (S22).

As shown in FIG. 5, when the gate is cut off, the MG rotation speed Nm and the capacitor voltage Vc have a positive correlation. The capacitor voltage Vc increases as the MG rotation speed Nm increases.
On the other hand, voltage control can be executed within the range of voltage control execution conditions. Specifically, the present invention can be executed within a range in which the MG rotation speed Nm is between the lower limit value NmL and the upper limit value NmH, and the capacitor voltage Vc is between the lower limit value VcL and the upper limit value VcH. In this range, the capacitor voltage Vc is controlled in accordance with a command from the MG-ECU 54.

Practically, there is a problem of preventing hunting when the MG rotation speed Nm changes over the upper limit value NmH in the range of the voltage control execution condition. Therefore, in the present embodiment, as shown in FIG. 6, a hysteresis for switching the control mode is set for the MG rotation speed Nm.
Specifically, the MG rotation speed Nm increases, and the rotation speed switching speed Nx + for switching from voltage control to gate cutoff is set to a value equal to or lower than the upper limit value NmH. On the other hand, the rotational speed Nx− of the deceleration switching that is switched from the gate cutoff to the voltage control when the MG rotational speed Nm decreases is set to a value smaller than the rotational speed Nx + of the acceleration switching. Thereby, in vehicle control device 50, when MG rotation speed Nm is in the vicinity of upper limit value NmH, it is possible to prevent control from becoming unstable due to frequent switching between voltage control and gate cutoff.

Subsequently, an operation example of the main battery abnormality process by the vehicle control device 50 will be described with reference to FIGS. Times t0, t1, and t3 indicated by common symbols on the time axes in the drawings mean the same timing. Moreover, the broken-line arrow in the vertical direction in each figure indicates the relevance of the state change. FIGS. 7 and 8 also show “TRC function off operation prohibition” and “MT mode operation prohibition” in common in the MG rotation suppression processing described above. On the other hand, “downshift prohibition at high speed travel” is shown only in FIG. In the vehicle control device 50, although not shown, an MG rotation suppression process such as “prohibition of deceleration blipping operation” may be executed instead of or in addition to these operation prohibition processes.

FIG. 7 shows a first operation example of the main battery abnormality process. In FIG. 7, as a comparative example with the first operation, an operation in the case where “prohibition of downshift at high speed” is not executed is indicated by a two-dot chain line. That is, in the comparative example, it is possible to downshift during high speed traveling.
In the initial stage before time t0, the inverter 40 is normally controlled. The capacitor voltage Vc is between the lower limit value VcL and the upper limit value VcH. MG rotation speed Nm is between lower limit value NmL and upper limit value NmH. The position of the transmission gear at this time is “5th speed”.

It is assumed that an abnormality has occurred in the main battery 20 at time t0. In this case, the power relay 21 is turned off. Thereafter, due to the discharge of the capacitor 25, the capacitor voltage Vc falls below the lower limit value VcL and falls to zero.
Assume that the MG 60 was in a powering operation before time t0. In this case, at time t1, MG-ECU 54 receives a voltage control command. And the vehicle control apparatus 50 prohibits each operation | movement of TRC function off and MT mode as MG rotation suppression processing. As a result, the vehicle control device 50 eliminates at least two factors that increase the MG rotation speed Nm accompanying the operation of the vehicle 901.
At this time, the MG-ECU 54 switches the inverter control mode from normal control to gate cutoff.

After time t1, the capacitor voltage Vc rises from zero by regenerative power generation of the MG 60. At time t3, the capacitor voltage Vc reaches the lower limit value VcL. The MG rotation speed Nm is between the lower limit value NmL and the upper limit value NmH. Therefore, the voltage control execution condition is satisfied. Therefore, MG-ECU 54 switches the inverter control mode from gate cutoff to voltage control.
Thereafter, the vehicle speed starts to decrease at time t5. At this time, in the comparative example, the clutch is released from the engaged state, the transmission gear is downshifted from, for example, “5-speed” to “3-speed”, and then the clutch is engaged again.
On the other hand, in the first operation example of the present embodiment, as shown in S12 of FIG. 4, if the vehicle speed is larger than the speed threshold value (during high speed traveling), the downshift of the transmission gear is prohibited. In the first operation example, the transmission gear is maintained at “5th speed” while the engine side clutch 81 is engaged.

As described above, in the comparative example, it is possible to downshift during high speed traveling. Therefore, in the comparative example, with the downshift, the MG rotation speed Nm increases before and after time t5 and exceeds the upper limit value NmH. Then, the capacitor voltage Vc rises and exceeds the upper limit value VcH. As a result, in the comparative example, an overvoltage is applied to the inverter 40 and the element may be damaged.
On the other hand, in the first operation example of the present embodiment, the downshift of the transmission gear during high speed traveling is prohibited. Thereby, in the 1st operation example of this embodiment, the increase in MG rotation speed Nm is suppressed and the raise of the capacitor voltage Vc can be prevented. Therefore, the vehicle control device 50 can protect the elements of the inverter 40 from overvoltage.

FIG. 8 shows a second operation example of the main battery abnormality process. It is assumed that an abnormality has occurred in the main battery 20 at time t0. In this case, at time t1, the vehicle control device 50 prohibits the TRC function off and the MT mode operations. Then, the vehicle control device 50 switches the inverter control mode from normal control to gate cutoff. The operation so far is the same as the first operation example of FIG. Therefore, the description is omitted here.
After time t1, the capacitor voltage Vc rises from zero by regenerative power generation of the MG 60. However, in the second operation example, MG rotation speed Nm exceeds upper limit value NmH at time t2 earlier than time t3 when capacitor voltage Vc reaches lower limit value VcL. Therefore, the voltage control execution condition is not satisfied even at time t3. Therefore, the inverter control mode is continued with the gate shut off.

At time t2 when the MG rotational speed Nm exceeds the upper limit value NmH, in the vehicle control device 50, the transmission ECU 58 places the engine-side clutch 81 in a half-engaged state in order to reduce the MG rotational speed Nm. That is, the engine side clutch 81 is slipped. Thereby, the power from engine 70 is not sufficiently transmitted to MG 60. Then, at time t4 when the MG rotation speed Nm falls below the upper limit value NmH, the transmission ECU 58 brings the engine side clutch 81 into the engaged state again. In the second operation example, the transmission ECU 58 may control the engine-side clutch 81 so as to intermittently repeat the engaged state and the semi-engaged state between time t2 and time t4.

After time t3, the capacitor voltage Vc is kept between the lower limit value VcL and the upper limit value VcH. Thereby, in vehicle control device 50, the element of inverter 40 can be protected from overvoltage.
At time t4, MG rotation speed Nm falls below upper limit value NmH. Therefore, the voltage control execution condition is satisfied. Therefore, MG-ECU 54 switches the inverter control mode from gate cutoff to voltage control.

As shown in FIG. 1, in the vehicle control system 10 to which the DCDC converter 30 is connected in parallel with the inverter 40, the DCDC converter 30 is driven simultaneously with the start of the voltage control. As a result, the vehicle control system 10 can supply low-voltage power to the auxiliary battery 32. As a result, in the vehicle control system 10, even if the main engine battery 20 is abnormal, the auxiliary machine load 33 can be driven using the regenerative power by the MG 60.
Therefore, the vehicle control system 10 can continue to supply power from the auxiliary battery 32 to the auxiliary load 33 such as a starter or an electric power steering device during the retreat travel when the main battery 20 is abnormal.

(Second Embodiment)
A second embodiment of the technology of the present disclosure will be described with reference to FIGS. 9 and 10. The second embodiment is applied to an axle split type vehicle 902 in which a wheel connected to the engine 70 and a wheel connected to the MG 60 are separated.
As shown in FIG. 9, the output shaft 71 of the engine 70 is connected to the drive shaft 91 via the transmission 83. The driving force transmitted to the drive shaft 91 is transmitted to the axle 93 via the differential gear 92. As a result, the front wheel 97 that is the driving wheel rotates. The MG 60 is connected to the rear wheel 98 via the axle 96. The inverter 40 converts the power of the main battery 20 and supplies it to the MG 60.
Note that the configuration of the present embodiment is not limited to the configuration shown in FIG. As another configuration, for example, the engine 70 may be disposed on the rear wheel side and the MG 60 may be disposed on the front wheel side.

In the present embodiment, as in the first embodiment, the vehicle control device 50 communicates with the main engine battery 20, the power relay 21, the inverter 40, the MG 60, the engine 70, the transmission 83, etc., and inputs various information. And output command signals.
In the axle split type vehicle 902, when the main engine battery 20 becomes abnormal and the power running operation of the MG 60 is stopped, the front wheel 97 is driven by the engine 70 to cause the vehicle 902 to travel. As a result, the rear wheel 98 is rotated by the traveling associated with the driving of the front wheel 97. As a result, the MG 60 generates regenerative power. If the voltage generated at this time becomes excessive (when a load dump occurs), the elements of the inverter 40 may be damaged by the overvoltage. Therefore, in the present embodiment, the vehicle control device 50 executes the MG rotation suppression process.

In this embodiment, the following method is mentioned as one of MG rotation suppression processes. For example, the vehicle control device 50 reduces the rotational speed of the front wheels 97 driven by the engine 70 to reduce the vehicle speed. Thereby, there is a method of reducing the MG rotation speed Nm. As another method, it is also effective to directly suppress the rotation of MG60.
FIGS. 10A to 10C show a configuration example for realizing MG rotation suppression in the axle split type vehicle 902. 10A to 10C, the driving configuration of the front wheels 97 by the engine 70 is the same as in FIG. Therefore, illustration is omitted and only the configuration on the rear wheel 98 side connected to the MG 60 is illustrated.

In the vehicle 902 having the configuration shown in FIG. 10A, a clutch 82 is provided on the drive shaft 94 that connects the MG 60 and the differential gear 95. For example, it is assumed that the vehicle 902 is traveling at a constant speed by driving the engine 70. In this state, vehicle control device 50 slips clutch 82 and reduces MG rotation speed Nm to upper limit value NmH or less. Thereafter, the vehicle control device 50 performs voltage control on the inverter 40 in the inverter control mode.

In the vehicle 902 having the configuration shown in FIG. 10B, a clutch 82 and a transmission 84 are provided on the drive shaft 94 that connects the MG 60 and the differential gear 95. For example, it is assumed that the vehicle 902 is traveling at a constant speed by driving the engine 70. In this state, vehicle control device 50 shifts the transmission gear to H (high), and reduces MG rotation speed Nm to an upper limit value NmH or less. Thereafter, the vehicle control device 50 performs voltage control on the inverter 40 in the inverter control mode.

In the vehicle 902 having the configuration shown in FIG. 10C, a clutch 82 is provided on each axle 96 that connects the MG 60 and the left and right rear wheels 98. For example, it is assumed that the vehicle 902 is traveling at a constant speed by driving the engine 70. In this state, vehicle control device 50 slips clutch 82 and reduces MG rotation speed Nm to upper limit value NmH or less. Thereafter, the vehicle control device 50 performs voltage control on the inverter 40 in the inverter control mode.
Thus, also in this embodiment, the same effect as the first embodiment can be obtained.

(Other embodiments)
(1) The MG rotation suppression process of the present disclosure is not limited to the content exemplified in the above embodiment. The MG rotation suppression process of the present disclosure includes all processes that exclude “a factor that increases the MG rotation speed Nm due to the operation of the vehicle”. That is, the MG rotation suppression process of the present disclosure includes all processes for suppressing the rotation of the MG 60 by prohibiting the operation of at least one of the factors that increase the MG rotation speed Nm due to the operation of the vehicle. It is.

(2) The vehicle control device of the present disclosure is not applied only to a vehicle control system including one motor generator. The vehicle control device of the present disclosure may be applied to a vehicle control system including, for example, two motor generators connected by a power split mechanism. Further, the vehicle control device of the present disclosure can be applied to a vehicle control system in which a part of regenerative power is supplied by a fuel cell.
As mentioned above, the technique of this indication is not limited to the content of the said embodiment. The technology of the present disclosure can be implemented in various forms without departing from the spirit of the disclosure.

10 ... Vehicle control system 20 ... Main machine battery (main machine power supply),
21 ... Power relay,
40: Inverter,
50 ... Vehicle control device,
60 ... MG (motor generator),
70 ... Engine,
81, 82 ... Clutch 84 ... Transmission,
901, 902 ... vehicle,
96 ... Axle.

Claims

It is applied to a vehicle (901, 902) equipped with an engine (70) and a motor generator (60), which are power sources, and a main power source (20) capable of transferring power to and from the motor generator via an inverter (40). , Controlling the operation of the engine and the motor generator, and at least one of power transmission between the engine and the motor generator and power transmission between the motor generator and the axle (96). A vehicle control device capable of controlling
A power control unit (52) for shutting off a power running operation of the motor generator by shutting off a power relay (21) provided between the main power source and the inverter when an abnormality of the main power source is detected; ,
A rotation suppression process that suppresses rotation of the motor generator by eliminating at least one of the factors that increase the rotation speed (Nm) of the motor generator due to the operation of the vehicle while maintaining vehicle traveling by the engine. A vehicle control device comprising: a main control unit (51) that instructs the other control units (54, 57, 58) to execute the above.
In the rotation suppression process,
Directly transmitted to the motor generator, or indirectly transmitted as the vehicle travels, suppressing rotation of the engine, or
The vehicle control device according to claim 1, wherein rotation of the motor generator is directly suppressed.
It is applied to vehicles that can execute traction control that suppresses the rotation of relatively fast wheels,
In the rotation suppression process,
The vehicle control device according to claim 1, wherein the main control unit prohibits the driver from stopping the traction control.
Applies to vehicles that can switch between automatic transmission mode and manual transmission mode,
The other control unit includes a transmission control unit (58),
In the rotation suppression process,
The vehicle control device according to any one of claims 1 to 3, wherein the transmission control unit prohibits the operation in the manual transmission mode.
The other control unit includes an engine control unit (57),
In the rotation suppression process,
The vehicle control device according to any one of claims 1 to 4, wherein the engine control unit prohibits an operation of deceleration blipping that increases a rotation speed (Ne) of the engine when the vehicle is decelerated.
Applied to a vehicle including a transmission (83, 84) capable of shifting the power transmitted between the engine and the motor generator or between the motor generator and an axle;
The other control unit includes a transmission control unit (58),
In the rotation suppression process,
The vehicle control device according to any one of claims 1 to 5, wherein the transmission control unit prohibits a downshift of the transmission when a vehicle speed is greater than a speed threshold value.
Applied to a vehicle including an engine side clutch (81) for intermittently transmitting power between the engine and the motor generator;
The other control unit includes a transmission control unit (58),
After execution of the rotation suppression process, the transmission control unit
When the rotational speed of the motor generator exceeds a predetermined upper limit (NmH), the engine-side clutch is brought into a half-engaged state,
When the rotational speed of the motor generator is below a predetermined upper limit (NmL), the engine side clutch is engaged,
The vehicle control device according to any one of claims 1 to 6, wherein the engine-side clutch is controlled to repeat the engagement state and the half-engagement state.
The other control unit includes an inverter control unit (54) for controlling the operation of the inverter based on the detected or estimated rotation speed of the motor generator,
The inverter control unit
After the abnormality of the main engine power supply is detected and the power supply relay is cut off, it is determined whether or not a predetermined voltage control execution condition is satisfied,
The voltage across the capacitor (25) provided on the main power supply side of the inverter by operating the operations of the plurality of switching elements (41-46) of the inverter when the voltage control execution condition is satisfied Execute voltage control to control the capacitor voltage (Vc),
The vehicle control device according to any one of claims 1 to 7, wherein when the voltage control execution condition is not satisfied, gate cutoff is performed to turn off the plurality of switching elements of the inverter.
The inverter control unit
9. The vehicle control device according to claim 8, wherein whether or not the rotation speed of the motor generator is within a predetermined rotation speed range and the capacitor voltage is within a predetermined voltage range is determined as the voltage control execution condition. .
In switching between the voltage control and the gate cutoff control mode according to the change in the rotation speed of the motor generator,
The speed change speed (Nx +) at which the control mode is switched when the motor generator speed increases is set to a value equal to or lower than the upper limit value of the motor generator speed,
10. The rotation speed (Nx−) of deceleration switching at which the control mode is switched when the rotation speed of the motor generator decreases is set to a value smaller than the rotation speed of the acceleration switching. The vehicle control device described in 1.
It is applied to a vehicle (901, 902) equipped with an engine (70) and a motor generator (60), which are power sources, and a main power source (20) capable of transferring power to and from the motor generator via an inverter (40). , Controlling the operation of the engine and the motor generator, and at least one of power transmission between the engine and the motor generator and power transmission between the motor generator and the axle (96). A vehicle control method by a vehicle control device capable of controlling
A step (S5, S6) of stopping a power running operation of the motor generator by shutting off a power supply relay (21) provided between the main power supply and the inverter when an abnormality of the main power supply is detected; ,
Suppressing the rotation of the motor generator by eliminating at least one of the factors that increase the rotational speed (Nm) of the motor generator by the operation of the vehicle while maintaining the vehicle running by the engine (S10) And a vehicle control method.
A computer-readable recording medium,
A recording medium storing a vehicle control program for causing a computer to execute the steps of the vehicle control method according to claim 11.