凸极式永磁无刷直流电机直接转矩控制研究

Research on Direct Torque Control of Salient PM Brushless DC Motor

提出并分析研究了一种凸极式永磁无刷直流电机定子磁链幅值不控型直接转矩控制策略。结合凸极式永磁无刷直流电机及其两相导通工作特点,全面建立起两相导通时电压矢量对电磁转矩控制理论。采用转矩单环控制,根据转矩滞环比较输出和定子磁链位置给出所施加的电压矢量,实现转矩的快速控制。推导出两相静止坐标系下电磁转矩计算模型,并针对实际无刷电机转子反电势既非理想梯形波,又非正弦波的情况,提出采用查表方式获得转矩观测所必需的转子反电势和转子磁链方法。实验结果表明,所提控制方案具有快速的动态响应和良好的稳态性能。

A novel direct torque control strategy of salient permanent magnetic brushless DC motor （BLDCM） without control for stator flux linkage amplitude was proposed combining with the characteristics of salient BLDCM and its operating mode with two phase conduction. This novel DTC adopts a single hysteresis-controlled torque loop to realize the rapid torque control by voltage vectors according to torque hysteresis comparison output and the position of stator flux linkage. The control theory of electromagnetic torque was set up using voltage vector in two phase conduction mode and the electromagnetic torque calculation mode was deduced in two phase static reference frame. A method of table lookup gaining the rotor back electromotive force （EMF） and flux linkage was applied to calculate torque as the BLDCM rotor back EMF is neither sinusoid nor trapezoid. Experimental results show that the proposed salient BLDCM DTC drive system has a quick dynamic response and good steady performance.