Motor counter electromotive force sampling module and sampling method

Abstract

The invention discloses a motor counter electromotive force sampling module, which comprises: a motor driving unit for outputting PWM to a driving circuit according to a control duty ratio, wherein the driving circuit outputs a preset waveform motor driving voltage, stops outputting PWM after receiving a counter electromotive force sampling interrupt signal and continues for Tbreak duration, and outputs PWM to recover the preset waveform motor driving voltage after the Tbreak duration is finished; a motor control unit for calculating the required control duty ratio according to a target rotating speed and the actual rotating speed calculated by counter electromotive force, transmitting the duty ratio to the motor driving unit, and generating a counter electromotive force sampling interruptsignal to the motor driving unit and a sampling interrupt unit at an interval (Twork + Tbreak); and the sampling interrupt unit for performing motor end voltage sampling after timing Twait duration.The invention also discloses a motor counter electromotive force sampling method. According to the invention, the motor counter electromotive force sampling is not limited by the counter electromotiveforce sampling frequency and the duty ratio any more, and more space is provided for solving the NVH problem of a vehicle body stabilizing system.

Description

technical field [0001] The invention relates to the field of automobiles, in particular to a motor back EMF sampling module used for a DC brushed motor in a body stabilization system. The invention also relates to a motor back electromotive force sampling method for a DC brushed motor of a vehicle body stabilization system. Background technique [0002] The body stabilization system (ESC) is composed of a controller, a valve block, and a motor. There are two oil inlets on the valve block, which communicate with the two chambers of the brake master cylinder respectively, and four oil outlets, respectively connected with the four chambers of the brake master cylinder. Brake wheel cylinder connection of the wheel, refer to figure 1 shown. The main working principle of the body stabilization system is to judge the vehicle stability based on driver input (brake pedal, steering wheel angle) and sensor signals (master cylinder pressure, wheel speed, acceleration, yaw rate). At t...

AI Technical Summary

Problems solved by technology

This method has two disadvantages. One is that the motor control PWM frequency cannot be higher than 1 / Twait, otherwise the motor terminal voltage cannot be restored to a stable back EMF within Toff time; the second is that the motor control PWM duty cycle cannot be higher than Ton / ( Ton+Twait), otherwise it will also cause the terminal voltage to fail to recover to a stable back EMF, which affects the performance of motor control

With the improvement of the NVH (Noise, Vibration and Harshness) requirements of the body stabilization system, the frequency of the motor control PWM is also gradually increased, and the traditional back EMF sampling method can no longer meet the needs of high-frequency control.

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