A steep slope descent method and device applied to electric vehicles

Abstract

The invention provides a hill descent control method and device applied to an electric automobile. The speed is subjected to derivation to obtain the accelerated speed, an accelerator pedal signal and an accelerated speed signal are monitored, and when the accelerator pedal signal is smaller than a first threshold value and the accelerated speed signal is larger than a second threshold value, the road condition of a steep hill where the automobile is located is judged, and the electric automobile is made to travel stably at a low speed on the steep hill by continuously adjusting output of the reverse torque according to the accelerated speed and the speed. According to the scheme, since the devices such as a slope sensor are not needed, the cost of the finished automobile is lowered; the sampling time of the motor rotating speed is shorter than that of the slope sensor, the sampling precision is high, and the response is sensitive. Meanwhile, the reversed torque can be further used for energy recovery, the utilization rate of energy is improved, and abrasion of a brake system is reduced.

Description

technical field [0001] The present invention relates to the technical field of electric vehicles, and more specifically, relates to a steep slope descent method and device applied to electric vehicles. Background technique [0002] At present, most pure electric vehicles are driven by permanent magnet synchronous motors. They are not equipped with gearboxes and cannot control the downhill speed by changing gears. Therefore, when going down a steep slope, high-speed loss of control is prone to occur. Therefore, the safety protection strategy is mainly designed so that the electric vehicle can run stably at low speed when going down a steep slope, avoiding the phenomenon of high-speed out of control, and improving the safety of the vehicle. The existing safety protection strategy is to detect the slope value through the slope sensor, and control the electric vehicle to drive in different speed ranges according to different slopes. However, the existing security protection str...

AI Technical Summary

Problems solved by technology

However, the existing security protection strategy needs to rely on the slope sensor to detect the slope value, which increases the cost of components, and because the slope sensor has a long sampling time and is easily disturbed by the external environment, the existing security protection strategy is relatively safe. Low

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