Vehicle control device

Abstract

To more reliably turn off a relay in a state where a current is not flowing.SOLUTION: A vehicle control device is used for a vehicle having: a motor for traveling; an inverter for driving the motor; a power storage device; a step-up converter connected between a first power line from the inverter and a second power line from the power storage device; and a relay attached to the second power line. The vehicle control device includes: a first control section for controlling the inverter and the step-up converter; and a second control section for communicating with the first control section and controlling the relay. When an abnormality occurs in communication with the second control section, the first control section shuts off gates of the inverter and the step-up converter. When an abnormality occurs in communication with the first control section, the second control section turns off the relay on and after elapse of a predetermined time from the occurrence of the abnormality in communication with the first control section.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a control device for a vehicle. [Background technology]

[0002] Conventionally, a vehicle control device of this type has been proposed for use in a vehicle having a motor, an inverter, a battery, and a relay attached to a power line between the battery and the inverter, and includes a first control unit that generates commands to the motor and controls the relay, and a second control unit that communicates with the first control unit and controls the inverter (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-127126 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, a vehicle control device has been proposed in which the relay is controlled by a control unit different from the first control unit. In such a device, it is recognized that an important issue is to turn off the relay in a state where no current is flowing when an abnormality occurs in communication between the first control unit and the control unit that controls the relay.

[0005] A primary object of the vehicle control device disclosed herein is to more reliably turn off the relay when no current is flowing. [Means for solving the problem]

[0006] The vehicle control device of the present disclosure employs the following means to achieve the above-mentioned main object. The vehicle control device of the present disclosure is used in a vehicle having a motor for driving, an inverter for driving the motor, a power storage device, a boost converter connected between a first power line from the inverter and a second power line from the power storage device, and a relay attached to the second power line, and includes a first control unit for controlling the inverter and the boost converter, and a second control unit for communicating with the first control unit and controlling the relay, wherein the first control unit shuts off a gate of the inverter and the boost converter when an abnormality occurs in communication with the second control unit, and the second control unit turns off the relay after a predetermined time has elapsed since the abnormality occurs in communication with the first control unit when an abnormality occurs in communication with the first control unit. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20. [Diagram 2] FIG. 2 is a diagram showing an outline of the configuration of an electric drive system including motors MG1 and MG2. [Diagram 3] 11 is a flowchart showing an example of a processing routine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with a vehicle control device of the present embodiment. Fig. 2 is a schematic diagram showing the configuration of an electric drive system including motors MG1 and MG2. As shown in Fig. 1, the hybrid vehicle 20 of the present embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, a motor ECU 40, inverters 41 and 42, a battery (electricity storage device) 50, a battery ECU (second control unit) 52, and an HVECU (first control unit) 70.

[0009] The engine 22 is configured as an internal combustion engine that outputs power using gasoline, diesel, or the like as fuel. The operation of the engine 22 is controlled by the engine ECU 24. The engine ECU 24 is configured as a microprocessor centered on a CPU, and includes a ROM, a RAM, an input / output port, and a communication port in addition to the CPU. Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 through an input port. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 through an output port. The engine ECU 24 is connected to the HVECU 70 through a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr from a crank position sensor.

[0010] The planetary gear 30 is configured as a single-pinion planetary gear mechanism, with the rotor of the motor MG1 connected to the sun gear, the drive shaft 36 connected to the drive wheels 39a, 39b via a differential gear 38 to the ring gear, and the crankshaft 26 of the engine 22 connected to the carrier.

[0011] The motors MG1 and MG2 are configured as known synchronous generator motors. As shown in Fig. 2, the inverters 41 and 42 are configured with transistors T11-T16 and T21-26, and diodes D11-D16 and D21-D26 connected in parallel in the reverse direction to the transistors T11-T16 and T21-T26. The transistors T11-T16 and T21-T26 are arranged in pairs of two each on the source side and sink side with respect to the positive and negative bus bars of the high-voltage power line (first power line) 54a, and the three-phase coils (U-phase, V-phase, W-phase) of the motors MG1 and MG2 are connected to the connection points between the paired transistors. A smoothing capacitor 57 is connected to the positive and negative bus bars of the high-voltage power line 54a.

[0012] 2, the boost converter 55 is configured as a boost converter including transistors T51 and T52, diodes D51 and D52 connected in parallel in the reverse direction to the transistors T51 and T52, and a reactor L. The transistors T51 and T52 are connected to the positive bus of the high-voltage power line 54a, and the negative bus of the high-voltage power line 54a and the low-voltage power line (second power line) 54b, respectively, and the reactor L is connected to the connection point of the transistors T51 and T52 and the positive bus of the low-voltage power line 54b. Therefore, by turning on and off the transistors T51 and T52, the power of the low-voltage power line 54b can be boosted and supplied to the high-voltage power line 54a, or the power of the high-voltage power line 54a can be reduced and supplied to the low-voltage power line 54b. A smoothing capacitor 58 is connected to the positive bus and the negative bus of the low-voltage power line 54b. A system main relay (relay) SMR is connected to the low-voltage side power line 54b on the battery 50 side from the connection point of the inverter 43.

[0013] The motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM, a RAM, an input / output port, and a communication port in addition to the CPU. Signals necessary for driving and controlling the motors MG1 and MG2 are input to the motor ECU 40 via an input port, such as rotational positions θm1 and θm2 from rotational position detection sensors that detect the rotational positions of the rotors of the motors MG1 and MG2, phase currents applied to the motors MG1 and MG2 detected by current sensors, a voltage (voltage of the high-voltage side power line 54a) VH of the capacitor 57 from a voltage sensor 57a attached between the terminals of the capacitor 57, and a voltage VL of the capacitor 58 from a voltage sensor 58a attached between the terminals of the capacitor 58. The motor ECU 40 outputs switching control signals to the transistors T11 to T16 and T21 to T26 of the inverters 41 and 42, switching control signals to the transistors T51 and T52 of the boost converter 55, and the like, via an output port. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 also calculates the rotation speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position detection sensors.

[0014] The battery 50 is configured as, for example, a lithium ion secondary battery, a nickel hydrogen secondary battery, a capacitor, or the like, and is connected to the inverter 43 and the boost converter 55 via a low-voltage side power line 54b. The battery 50 is managed by a battery ECU 52.

[0015] The battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM, a RAM, an input / output port, and a communication port in addition to the CPU. The battery ECU 52 receives the voltage Vb of the battery 50 from a voltage sensor attached between the terminals of the battery 50, the current Ib of the battery 50 from a current sensor attached to the output terminal of the battery 50, and the like via an input port. The battery ECU 52 outputs a control signal to the system main relay SMR. The battery ECU 52 is connected to the HVECU 70 via a communication port. The battery ECU 52 calculates the power storage percentage SOC of the battery 50 based on an integrated value of the current Ib of the battery 50 from the current sensor. The power storage percentage SOC is the percentage of the amount of power stored (the amount of power that can be discharged from the battery 50) relative to the total capacity of the battery 50.

[0016] The HVECU 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM, a RAM, an input / output port, and a communication port. An ignition signal from an ignition switch 80, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a vehicle speed V from a vehicle speed sensor 88, and the like are input to the HVECU 70 via the input port. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

[0017] The hybrid vehicle 20 of this embodiment configured as described above runs by switching between multiple driving modes, including a motor driving mode (EV driving) mode in which the vehicle runs without operating the engine 22, and a hybrid driving mode (HV driving) mode in which the vehicle runs with the engine 22 operating.

[0018] In the EV driving mode, the HVECU 70 first sets a required torque Td* required for driving based on the accelerator opening Acc and the vehicle speed V, sets a value of 0 to the torque command Tm1* of the motor MG1, sets a torque command Tm2* of the motor MG2 so that the required torque Td* is output to the drive shaft 36, and sets a target voltage VH* of the high-voltage power line 54a so that the motors MG1 and MG2 are driven efficiently. Then, the HVECU 70 transmits the set torque commands Tm1* and Tm2* and target voltage VH* of the motors MG1 and MG2 to the motor ECU 40. The motor ECU 40, which has received the torque commands Tm1* and Tm2* and the target voltage VH*, controls the switching of the transistors of the inverters 41, 42, and 43 so that the motors MG1 and MG2 are driven by the torque commands Tm1* and Tm2*, and controls the switching of the transistors of the boost converter 55 so that the voltage VH of the high-voltage power line 54a becomes the target voltage VH*.

[0019] In the HV driving mode, the HVECU 70 first sets a required torque Td* required for driving based on the accelerator opening Acc and the vehicle speed V, and then sets a required power Pd* required for driving based on the set required torque Td* and the vehicle speed V. Next, the HVECU 70 calculates a required power Pe* required for the vehicle by subtracting a charge / discharge required power Pb* (a positive value when the battery 50 is discharging) of the battery 50 from the required power Pd*, sets a target rotation speed Ne* and target torque Te* of the engine 22, and torque commands Tm1* and Tm2* of the motors MG1 and MG2 so that the required power Pe* is output from the engine 22 and the required torque Td* is output to the drive shaft 36, and sets a target voltage VH* for the high-voltage side power line 54a so that the motors MG1 and MG2 are driven efficiently. Then, the engine ECU 40 transmits the target rotation speed Ne* and target torque Te* of the engine 22 to the engine ECU 24, and also transmits torque commands Tm1*, Tm2* and target voltage VH* of the motors MG1, MG2 to the motor ECU 40. The engine ECU 24 receives the target rotation speed Ne* and target torque Te* and performs intake air amount control, fuel injection control, ignition control, etc. of the engine 22 so that the engine 22 is operated at the target rotation speed Ne* and target torque Te*. The control of the inverters 41, 42 and the boost converter 55 by the motor ECU 40 has been described above.

[0020] Next, a description will be given of the operation of the hybrid vehicle 20 equipped with the vehicle control device of this embodiment configured as described above, in particular, the operation when an abnormality occurs in the communication between the HVECU 70 and the battery ECU 52. Here, an example of the communication abnormality between the HVECU 70 and the battery ECU 52 is an abnormality in which the communication between the HVECU 70 and the battery ECU 52 is interrupted.

[0021] When the HVECU 70 determines that an abnormality has occurred in the communication with the battery ECU 52, the HVECU 70 transmits the target rotation speed Ne* of the engine 22 to the engine ECU 24 and transmits a gate shutoff command for the inverters 41, 42 and the boost converter 55 to the motor ECU 40. The target rotation speed Ne* is a value determined in advance by experiment, analysis, machine learning, etc. as the rotation speed Ne of the engine 22 when an abnormality has occurred in the communication between the HVECU 70 and the battery ECU 52. The engine ECU 24 that has received the target rotation speed Ne* controls the operation of the engine 22 so that the rotation speed Ne of the engine 22 becomes the target rotation speed Ne*. The motor ECU 40 that has received the gate shutoff command shuts off the gates of the inverters 41, 42 (turns off the transistors T11 to T16, T21 to T26) and shuts off the gates of the boost converter 55 (turns off the transistors T51, T52). When the gates of inverters 41, 42 are cut off while the vehicle is running, motors MG1, MG2 are rotating, and so current flows to high-voltage power line 54a via diodes D11-D16, D21-D26 of inverters 41, 42. In this embodiment, the gate of boost converter 55 is cut off to prevent current from flowing to low-voltage power line 54b.

[0022] FIG. 3 is a flowchart showing an example of a processing routine executed by the battery ECU 52. This routine is executed when the battery ECU 52 determines that an abnormality has occurred in communication with the HVECU 70. When the processing routine is executed, the CPU of the battery ECU 52 determines whether or not a predetermined time tref has elapsed since it was determined that an abnormality has occurred in communication with the HVECU 70 (S100). The predetermined time tref is a time determined in advance by experiment, analysis, machine learning, or the like as a time until the current flowing through the low-voltage side power line 54b becomes zero after the HVECU 70 transmits a gate interruption command to the inverters 41 and 42 and the boost converter 55, or a time slightly longer than the time until the current flowing through the low-voltage side power line 54b becomes zero. Therefore, the processing of S100 is a processing for determining whether or not the current flowing through the low-voltage side power line 54b becomes zero.

[0023] If the predetermined time tref has not elapsed since it was determined in S100 that an abnormality has occurred in communication with the HVECU 70, the routine waits until the predetermined time tref has elapsed since it was determined that an abnormality has occurred in communication with the HVECU 70, turns off the system main relay SMR at a predetermined timing after the predetermined time tref has elapsed since it was determined that an abnormality has occurred in communication with the HVECU 70 (S110), and ends this routine. This makes it possible to turn off the system main relay SMR when the current flowing through the low-voltage side power line 54b becomes zero. Therefore, it is possible to more reliably turn off the system main relay SMR in a state where no current is flowing.

[0024] According to the hybrid vehicle 20 equipped with the vehicle control device of the present embodiment described above, when an abnormality occurs in communication with the battery ECU 52, the HVECU 70 and the motor ECU 40 gate-off the inverters 41, 42 and the boost converter 55, and when an abnormality occurs in communication with the battery ECU 52, the battery ECU 52 turns off the system main relay SMR after a predetermined time tref has elapsed since the abnormality occurred in communication with the HVECU 70, so that the system main relay SMR can be more reliably turned off when no current is flowing.

[0025] In the above-described embodiment, the hybrid vehicle 20 includes the boost converter 55. However, in a hybrid vehicle 20 that does not include the boost converter 55 and has a system main relay SMR attached to the power line between the battery 50 and the inverter 41, when the HVECU 70 determines that an abnormality has occurred in the communication with the battery ECU 52, the HVECU 70 may control the inverters 41, 42 so that the currents of the motors MG1, MG2 become zero. In this way, the system main relay SMR can be turned off with the current flowing through the power line between the battery 50 and the inverter 41 being set to zero.

[0026] In the above-described embodiment, the inverters 41, 42 and the boost converter 55 are controlled in cooperation with the motor ECU 40 and the HVEU 70, but they may be controlled only by the HVEU 70. The present disclosure may also be applied to a so-called one-motor hybrid vehicle in which the engine and the motor are connected via a clutch, or an electric vehicle that is not equipped with an engine and runs on power from a motor.

[0027] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the embodiment is an example for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the Means for Solving the Problem column.

[0028] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure. [Explanation of symbols]

[0029] 52 Battery ECU, 70 HVECU.

Claims

[Claim 1] A vehicle control device is used in a vehicle having a motor for driving the motor, an inverter for driving the motor, a power storage device, a boost converter connected between a first power line from the inverter and a second power line from the power storage device, and a relay attached to the second power line, the vehicle control device comprising: a first control unit for controlling the inverter and the boost converter; and a second control unit for communicating with the first control unit and controlling the relay, the first control unit cuts off gates of the inverter and the boost converter when an abnormality occurs in communication with the second control unit; When an abnormality occurs in communication with the first control unit, the second control unit turns off the relay after a predetermined time has elapsed since the abnormality occurred in communication with the first control unit. Vehicle control device.

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