A Brushless DC Motor Torque Ripple Reduction Method For Electric Vehicle Drive Motor

With the development of the automobile industry, vehicle exhaust is a problemthat people have to consider. Electric vehicles for its "zero emissions" and attractedwidely attention. In the electric vehicle drive motors, brushless DC motors account fora large part of it. The main goal of this paper is to study the use of the electric vehicledrive brushless DC motor, how to reduce torque ripple charged.At the time of this analysis of the causes of the brushless DC motor commutationtorque ripple, shows brushless DC motor as the motor inductance exists sake, so thatthe motor current cannot be quickly reaches a preset value, the resulting producemotor torque ripple. This article analyzes the commutation process, draw, when theline voltage brushless DC motor is four times when the back EMF commutationtorque ripple minimum. And the conclusion can be verified by Matlab simulationmodel. Because the brushless DC motor is running at steady speed because the load ismutated, only if the brushless DC motor torque ripple optimal control without speedcontrol, brushless DC motor torque ripple will not be lowered, or even dangerousmoments of downtime. Therefore, when the brushless DC motor as an electric vehicledrive motor, the motor speed needs to be controlled. Most of the brushless DC motorspeed control using PI control steady speed, in order to better setting PID values, thispaper presents the PID parameters based on ITAE and overshoot indicators tuningmethod. Matlab function using a nonlinear least squares, according to the PIDparameter optimization ITAE indicators and overshoot, optimized for Kp, Ki and Kdachieve PID parameter tuning. On the basis of the transfer function model of BLDCMestimates BLDCM area method using various parameters and study several PID tuning methods: classical Z-N method, CHR method, Cohen-Coon method, IMCmethod, IST2E optimal PID Act and ITAE method and the optimal settingsITAE-overshoot method. The simulation results showed that:1,the PID parameterscan obtain better closed-loop speed control, speed overshoot is small and fast response.2, when the line voltage is four times the value of the electromotive force canobtained the minimum commutation torque ripple.