基于换相过程分析的无刷直流电动机机械特性的研究

RESEARCH ON THE MECHANICAL CHARACTERISTIC OF BRUSHLESS DC MOTORS BASED ON THE ANALYSIS OF PHASE COMMUTATION

通过对三相星型六状态工作模式下无刷直流电动机的换相过程进行分析,列出换相过程的微分方程,推导了相绕组导通期间平均电流的解析表达式,并利用该解析表达式,借助Matlab进行仿真计算,深入研究了无刷直流电动机的机械特性。通过与实验数据的对比,验证了该分析计算方法的正确性。指出无刷直流电动机机械特性的计算不能直接套用有刷直流电机的计算方法,是因为绕组电感不能忽略,进而揭示了绕组电感也是影响电压源型直流电源供电的无刷直流电动机机械特性的主要因素,并总结了其影响的规律性,为无刷直流电动机机械特性的改善提供了方法和依据。

The phase commutation of brushless DC motors with three-phase Y-connected windings in six-state operate mode was analyzed. And the analytical expression of the average phase current in conduction state was derived from the differential equations of the phase commutation. Based on the expression of the average phase current, the mechanical characteristic of brushless DC motor was computed using Matlab. And the analysis was validated by experimental results.Since the phase inductance can＇t be neglected, the method of computing the mechanical characteristic of brush-type DC motors can＇t be employed directly to predict the mechanical characteristic of brushless DC motors. The phase inductance has primary effect on the mechanical characteristic of brushless DC motors fed from the voltage source inverter, and how it impacts the mechanical characteristic is analyzed to present the method of improving the mechanical characteristic.