CN-122029073-A - Method for operating an electric vehicle and control device for an electric vehicle

Abstract

The invention relates to a method for operating an electric vehicle (10), comprising determining (S1) whether a recuperation operation is performed on an electric motor of the electric vehicle during a predetermined monitoring period, providing (S2) or determining a target value for a recuperation torque on the electric motor, determining (S3) a rotational speed of the electric motor that is in recuperation operation during the predetermined monitoring period, determining (S4) a torque of the electric motor that is in recuperation operation during the predetermined monitoring period, determining (S5) a tire torque on at least one drive wheel of the electric vehicle from the rotational speed and the torque of the electric motor that is in recuperation operation, optimizing (S6) the tire torque according to a predetermined process, and adjusting (S7) the rotational speed and/or the torque of the electric motor based on this, wherein the tire torque is kept outside the locking condition of the at least one drive wheel.

Inventors

• P. Oborowski

Assignees

• 罗伯特·博世有限公司

Dates

Publication Date

20260512

Application Date

20241008

Priority Date

20231018

Claims (10)

1. 1. A method for operating an electric vehicle (10), comprising the steps of: -determining (S1) whether a recovery operation is performed on the electric machine of the electric vehicle during a predetermined monitoring period; -providing (S2) or finding a target value of the recuperation torque on the electric machine; -determining (S3) the rotational speed of the motor in the recovery operation during the predetermined monitoring period; -determining (S4) the torque of the electric machine in the recovery operation during the predetermined monitoring period; -determining (S5) a tyre torque on at least one driving wheel of the electric vehicle from the rotational speed and the torque of the motor in the recovery operation; -optimizing (S6) the tyre torque according to a preset process and adjusting (S7) the rotational speed and/or the torque of the motor based thereon, wherein the tyre torque is kept outside the locking condition of the at least one driving wheel.
2. 2. The method of claim 1, implemented on a control device of an inverter of the electric machine.
3. 3. The method according to claim 1 or 2, wherein the target value of the recovery torque is preset by a driver.
4. 4. A method according to any one of claims 1 to 3, wherein the torque is maintained within a predetermined deviation from the target value of the recovered torque.
5. 5. The method according to any one of claims 1 to 4, wherein the tire torque is optimized such that the tire torque has a maximum value according to the wheel slip of the at least one drive wheel.
6. 6. The method of claim 5, wherein the tire torque is optimized such that periodic increases and decreases in the rotational speed are achieved.
7. 7. A method according to claim 6, wherein the rotational speed is reduced until a state is reached in which the subsequent variation of the tire torque is reduced or maintained due to the reduction of the rotational speed, and in which case the rotational speed is subsequently maintained or increased as long as the subsequent tire torque is increased, otherwise the rotational speed is reduced again.
8. 8. Control device (SE) for an electric vehicle, designed to perform the method according to any one of claims 1 to 7.
9. 9. The control device (SE) according to claim 8, being a control device of an inverter of the electric vehicle.
10. 10. Control device (SE) according to claim 8 or 9, which is connected to or comprises a rotational speed sensor and/or a torque sensor of the electric machine.

Description

Method for operating an electric vehicle and control device for an electric vehicle Technical Field The present invention relates to a method for operating an electric vehicle and a control device for an electric vehicle. Background The recuperation function can be performed during operation of the electric vehicle, wherein a deceleration of the vehicle can be achieved by the electric drive train if the driver releases the accelerator pedal and does not actuate the brake pedal. The implementation and control of such recycling functions may be implemented in a vehicle computing device. The vehicle computing device may read the accelerator pedal position and send and preset a target torque to an inverter of the drive system. The maximum deceleration of the vehicle may be limited by recovery via the vehicle computing device and by a preset of target torque. In the case of slippery road surfaces, there is the possibility that the drive wheel may lock up when the tire is no longer transmitting torque to the road surface. In general, monitoring of recovery functions by means of a vehicle stability system computing device (ESP/ABS) can be used in vehicles, wherein locking of the wheels can be detected by means of sensors of the vehicle. If the wheels are subject to locking in the event of a recovery, the system may send a request to the vehicle computing device or directly to the inverter to reduce or completely shut down the recovery torque. A drive train of an all-wheel drivable vehicle is described in WO 2013/083243 A1. Disclosure of Invention The invention provides a method for operating an electric vehicle according to claim 1 and a control device for an electric vehicle according to claim 8. The invention is based on the idea of specifying a method for operating an electric vehicle and a control device for an electric vehicle, wherein the recovery operation can be monitored by a vehicle stability system calculation device. For this purpose, the recovery function can independently prevent the wheel from locking, or at least reduce the probability of locking, wherein only measured variables of the rotational speed and torque of the motor are required, so that the method can be implemented particularly simply in the computing device of the inverter. According to the invention, in a method for operating an electric vehicle, it is determined whether a recuperation operation is performed on a motor of the electric vehicle during a predetermined monitoring period, a target value of a recuperation torque on the motor is provided or determined by a control device, a rotational speed of the motor in recuperation operation during the predetermined monitoring period is determined, a torque of the motor in recuperation operation during the predetermined monitoring period is determined, a tire torque on at least one drive wheel of the electric vehicle is determined from the rotational speed and the torque of the motor in recuperation operation, the tire torque is optimized according to a preset process (and according to a preset condition), for example by a preset setting value for adjusting the rotational speed of the motor, and the rotational speed and/or the torque of the motor is adjusted on the basis of this, wherein the tire torque is kept outside of a locking condition of at least one drive wheel (for example a motor rotational speed change associated with a recuperation torque change). Advantageously, the method makes it possible to achieve the predetermined or desired recovery torque as accurately as possible, while preventing or at least reducing the probability of locking the drive wheel. According to a preferred embodiment of the method, the method is implemented on a control device of an inverter of the electric machine. According to a preferred embodiment of the method, the target value of the maximum recuperation torque is preset by the driver. The driver can preset the maximum recuperation torque by means of the vehicle computing device. If wheel lock-up is possible, the maximum recuperation torque is limited by the control device. According to a preferred embodiment of the method, the torque is maintained within a predetermined deviation from a target value of the recovered torque. According to a preferred embodiment of the method, the tire torque is optimized such that it has a maximum value according to the wheel slip of the at least one driving wheel. According to a preferred embodiment of the method, the tire torque is optimized such that periodic increases and decreases of the rotational speed are achieved. According to a preferred embodiment of the method, the rotational speed is reduced until a state is reached in which the subsequent change in the tire torque is reduced or remains unchanged as a result of the reduction in rotational speed, and in this case the rotational speed is subsequently maintained or increased as long as the subsequent tire torque is increased, otherwise the rotational speed