一种基于电流反馈的分段式PWM控制无刷直流电机转矩波动抑制方法

摘要

The brushless DC motor (BLDCM) servo systems have been widely used in industry applications.But the torque ripple limits the using range of the BLDCM in high precision conditions.This paper propose a novel hybrid PWM control method based on current feedback to reduce the torque ripple in BLDCM with non-ideal back-EMF.The reference current used to produce the target torque is obtained through back-EMF observer,and the proposed control method realizes the torque direct control.Two different PWM control strategies are used to suppress the commutation torque ripple at high and low speeds.The system with the proposed method has the features of low torque ripple and large torque output.Simulation and experimental are set up with Matlab/Simulink to prove the torque control and compare torque ripple.Simulation and experiment results show the proposed method can significantly eliminate the torque ripple and enhance the accuracy of position control for servo system.%无刷直流电机伺服系统具有广泛的应用场合,但转矩波动限制了其在高精度场合的应用.针对非理想反电动势引起的无刷直流电机转矩波动提出了一种基于电流反馈的分段式PWM控制方法.该方法通过线反电动势观测器获得产生目标转矩值的参考电流,以实现对电机转矩的直接控制.同时,针对电机高速与低速运行状态分别采用不同的PWM控制策略来有效消除换相转矩波动,系统具有低转矩波动和高转矩输出的特点.通过在Matlab/Simulink环境下建立系统仿真模型,对该控制方法的转矩直接控制能力进行检验,并对转矩波动进行了对比;搭建实验平台对具有非理想反电动势的无刷直流电机进行了驱动实验.仿真和实验结果表明,该文所提出的控制方法能有效减小转矩波动,提高无刷直流电机伺服系统输出转矩的稳定性和位置控制精确度.