Control device for electric vehicle

Abstract

To suppress generation of vibration noise from a motor during execution of temperature rise processing of a battery.SOLUTION: A determination unit configured to determine whether or not a rotation angle position of the motor in a case where the electric vehicle is stopped and an execution condition of the temperature rise processing is satisfied is within an executable angle range in which a compelling force to the motor generated in a case where the motor is energized in association with execution of the temperature rise processing is equal to or less than a predetermined value; A motor control section that moves the rotation angle position of the motor into the executable angle range after the interruption of the power transmission; and a temperature raising control section that causes the temperature raising device to execute the temperature raising process after the movement of the rotation angle position of the motor into the executable angle range.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device for an electric vehicle. [Background technology]

[0002] There is a vehicle equipped with a heating device that is electrically connected between a battery and a motor to perform a heating process to raise the temperature of the battery and energize the motor in conjunction with the execution of the heating process (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-182013 Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, current flows through the motor when the temperature rise process is performed. This current flow may cause vibration noise from the motor. For example, if such vibration noise occurs while the vehicle is stopped, it may cause discomfort to the driver.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device for an electric vehicle that suppresses the generation of vibration noise from a motor accompanying the execution of a battery temperature raising process. [Means for solving the problem]

[0006] The above object can be achieved by a control device for an electric vehicle having a cut-off mechanism capable of cut-off power transmission from a motor to a wheel, a battery that supplies power to the motor, and a heating device that is electrically connected between the battery and the motor to perform a heating process to heat up the battery and to energize the motor in conjunction with the execution of the heating process, the control device for an electric vehicle including: a determination unit that determines whether the rotational angle position of the motor when the electric vehicle is stopped and an execution condition for the heating process is met is within a feasible angle range in which a force on the motor that is generated when the motor is energized in conjunction with the execution of the heating process is equal to or less than a predetermined value; a cut-off control unit that, if the determination unit makes a negative determination, cuts off the power transmission using the cut-off mechanism; a motor control unit that moves the rotational angle position of the motor within the feasible angle range after the power transmission is cut off; and a heating control unit that causes the heating device to execute the heating process after the rotational angle position of the motor has moved into the feasible angle range. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a control device for an electric vehicle that suppresses the generation of vibration noise from a motor accompanying the execution of a battery temperature raising process. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram of an electric vehicle. [Figure 2] 4 is a flowchart illustrating a battery temperature increase control. [Figure 3] 10 is a graph illustrating an example of a radial force depending on the electrical angle of the motor. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Outline of electric vehicle configuration] 1 is a schematic diagram of an electric vehicle 1. The electric vehicle 1 is an electric vehicle equipped with a motor 2 as a driving power source. The electric vehicle 1 is equipped with the motor 2, a clutch 3, a transmission 4, a differential gear 5, drive wheels 6, a PCU (Power Control Unit) 7, a battery 8, and an ECU (Electric Control Unit) 10.

[0010] The motor 2 functions as an electric motor that outputs torque when supplied with electric power. The motor 2 also functions as a generator that generates electricity when the electric vehicle 1 is braked. The PCU 7 includes an inverter that converts DC power from the battery 8 into AC power and supplies it to the motor 2. The PCU 7 also includes a converter that converts DC power generated by the motor 2 into AC power and charges the battery 8. The ECU 10 controls the PCU 7 to adjust the power exchanged between the motor 2 and the battery 8.

[0011] The motor 2 is connected to drive wheels 6 via a clutch 3, a transmission 4, and a differential gear 5. The torque of the motor 2 is transmitted to the drive wheels 6, causing the electric vehicle 1 to travel. The clutch 3 is engaged when supplied with hydraulic pressure, connecting the power transmission between the motor 2 and the drive wheels 6. The clutch 3 is released when the hydraulic pressure supply is stopped, disconnecting the power transmission between the motor 2 and the drive wheels 6. The clutch 3 is an example of a disconnecting mechanism.

[0012] The ECU 10 includes a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), and a storage device, and performs various controls by executing programs stored in the ROM and the storage device. The ECU 10 is an example of a control device for an electric vehicle, and functionally realizes a determination unit, a shutoff control unit, a motor control unit, and a temperature rise control unit, which will be described in detail later.

[0013] The ECU 10 is electrically connected to an ignition switch 20, a temperature sensor 21, a position sensor 22, and a vehicle speed sensor 23. The ignition switch 20 detects the on / off state of the ignition. The temperature sensor 21 detects the temperature of the battery 8. The position sensor 22 detects the rotational angle position of the motor 2, more specifically, the rotational angle position of the rotor of the motor 2. The position sensor 22 is, for example, a Hall element. The vehicle speed sensor 23 detects the traveling speed of the electric vehicle 1.

[0014] The ECU 10 controls a hydraulic control valve on a hydraulic circuit connected to the clutch 3 to engage or disengage the clutch 3. Furthermore, when a predetermined condition is met, the ECU 10 controls the switching of at least one of the inverter and converter of the PCU 7 to execute a temperature-raising process to raise the temperature of the battery 8. The temperature-raising process is a known method disclosed, for example, in Japanese Patent Application Laid-Open No. 2022-182013 and Japanese Patent No. 5293820. In the temperature-raising process, the PCU 7 supplies current to the battery 8, raising the temperature of the battery 8. In addition, a current also flows to the motor 2 in association with this temperature-raising process. The PCU 7 is an example of a temperature-raising device. The temperature-raising process may be, for example, a process of energizing at least one of the inverter and converter of the PCU 7 and raising the temperature of the battery 8 by the heat generated therefrom. In this case, a current also flows to the motor 2 in association with the energization of the inverter or converter.

[0015] [Battery temperature rise control] 2 is a flowchart illustrating the battery temperature increase control. This control is repeatedly executed while the ignition is on. The ECU 10 determines whether the electric vehicle 1 is stopped based on the detection value of the vehicle speed sensor 23 (step S1).

[0016] If the answer is Yes in step S1, the ECU 10 determines whether or not a condition for executing the temperature raising process for the battery 8 is met (step S2). The condition for executing the temperature raising process for the battery 8 is, for example, when the temperature of the battery 8 detected by the temperature sensor 21 is equal to or lower than a predetermined temperature indicating a low temperature. If the answer is No in step S1 or S2, this control ends.

[0017] If the answer is Yes in step S2, the ECU 10 determines whether the rotational angle position of the motor 2 is within the feasible angle range based on the detection value of the position sensor 22 (step S3). Steps S1 to S3 are an example of processing executed by the determination unit.

[0018] FIG. 3 is a graph illustrating the radial coercive force [N] as a function of the electrical angle [deg] of the motor 2. The radial coercive force varies depending on the electrical angle, i.e., the rotational angle position, of the motor 2. FIG. 3 also shows feasible angular ranges R1 and R2. The feasible angular ranges R1 and R2 are angular ranges within which the radial coercive force is equal to or less than a predetermined value P. The predetermined value P is set to a radial coercive force that does not cause the driver to notice the vibration noise of the motor 2 when the heating process is performed while the vehicle is stopped. Therefore, if the rotational angle position of the motor 2 is within the feasible angular ranges R1 and R2, the driver will not notice the vibration noise of the motor 2 even when the heating process is performed while the vehicle is stopped. The radial coercive force is calculated in advance through experiments, and the feasible angular ranges R1 and R2 are set based on the experimental results. If the rotational angle position of the motor 2 falls within either the feasible angular ranges R1 or R2, the determination is Yes. If the rotational angle position of the motor 2 does not belong to either the feasible angle range R1 or R2, the determination is No.

[0019] If the answer is No in step S3, the ECU 10 releases the clutch 3 (step S4). This interrupts the power transmission between the motor 2 and the drive wheels 6. Note that if the power of the motor 2 is not being transmitted to the drive wheels 6, the clutch 3 may be allowed to slip. Step S4 is an example of processing executed by the interruption control unit.

[0020] Next, the ECU 10 drives the motor 2 so as to move the rotational angle position of the motor 2 into either the feasible angle range R1 or R2 (step S5). For example, if the rotational angle position of the motor 2 is closer to the feasible angle range R1 than to the feasible angle range R2, the rotational angle position of the motor 2 is moved into the feasible angle range R1. If the rotational angle position of the motor 2 is closer to the feasible angle range R2 than to the feasible angle range R1, the rotational angle position of the motor 2 is moved into the feasible angle range R2. Step S5 is an example of processing executed by the motor control unit.

[0021] Next, the ECU 10 engages the clutch 3 (step S6). Next, the ECU 10 executes the temperature increase process (step S7). In this way, the temperature increase process is executed after the rotational angle position of the motor 2 is moved to either the executable angle range R1 or R2. Therefore, it is possible to suppress the vibration noise of the motor 2 that accompanies the execution of the temperature increase process. Step S7 is an example of the process executed by the temperature increase control unit. Note that the temperature increase process may be executed without executing step S6. Also, if the answer to step S3 is Yes, the temperature increase process is executed (step S7) without executing the above-mentioned steps S4 to S6.

[0022] In the above embodiment, the electric vehicle 1 is an electric vehicle, but this is not intended to be limiting. For example, the electric vehicle may be a hybrid vehicle equipped with an engine and a motor as a driving power source. Furthermore, while two feasible angle ranges R1 and R2 are shown in the example of FIG. 3 , there may be one feasible angle range or three or more feasible angle ranges. While the clutch 3 is described as an example of a disconnection mechanism, the disconnection mechanism may be, for example, a lock-up clutch provided in a torque converter. The map in FIG. 3 may be selected from multiple maps based on, for example, the temperatures of the motor 2 and the battery 8. Furthermore, in the above embodiment, the feasible angle ranges R1 and R2 are defined as angle ranges in which the radial force is equal to or less than a predetermined value P. However, this is not intended to be limiting. For example, if the force in the thrust direction or the circumferential direction is a problem with vibration noise from the motor 2, the feasible angle range may be an angle range in which the force in the thrust direction or the circumferential direction is equal to or less than a predetermined value, rather than the radial direction.

[0023] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0024] 1 Electric vehicles 2 motors 3. Clutch 7 PCU (heating unit) 10 ECU (electric vehicle control device, judgment unit, shutoff control unit, motor control unit, temperature rise control unit)

Claims

[Claim 1] A control device for an electric vehicle including a cut-off mechanism capable of cutting off power transmission from a motor to wheels, a battery that supplies power to the motor, and a heating device that is electrically connected between the battery and the motor, that executes a heating process to heat up the battery, and that energizes the motor in conjunction with the execution of the heating process, a determination unit that determines whether a rotational angle position of the motor when the electric vehicle is stopped and the execution condition of the temperature increase process is satisfied is within an executable angle range in which a force acting on the motor, which is generated when the motor is energized in association with the execution of the temperature increase process, is equal to or less than a predetermined value; a cutoff control unit that cuts off the power transmission by the cutoff mechanism when a negative determination is made by the determination unit; a motor control unit that moves a rotational angle position of the motor within the feasible angle range after the power transmission is interrupted; a temperature rise control unit that causes the temperature rise device to perform the temperature rise process after the rotational angle position of the motor is moved into the feasible angle range; A control device for an electric vehicle comprising:

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