无刷直流电机离散滑模观测器直接转矩控制

摘要

The reason of electromagnetic torque ripples for brushless DC motors (BLDCM) with the noni-deal back electromotive force (back-EMF) adopting the traditional pulse width modulation current control was analyzed. For ease of computer control,discrete-time sliding mode observers (DSMO) were used to obtain the back EMF to estimate electromagnetic torque, and the sliding and convergence condition for DSMO were proved. Based on this,the direct torque control for BLDCM was proposed. Voltage space vectors were decided by both the hysteresis-controlled torque loop output and position of magnetic poles. Electromagnetic torque ripples produced by both the nonideal back-EMF and low-speed current commutation could be restrained effectively. Simulated results validate the theory.%分析了非理想反电势下无刷直流电机传统脉宽调制电流控制产生电磁转矩脉动的原因.为便于计算机控制,采用离散滑模观测器获取无刷直流电机反电势,进而完成电磁转矩的估算,并证明了离散滑模观测器的到达条件和稳定条件.在此基础上,提出无刷直流电机直接转矩控制.该方法采用转矩滞环的输出和磁极位置来选择电压空间矢量,可有效抑制非理想反电势和低速换相电磁转矩脉动.仿真结果证明了其正确性.