双凸极永磁电机中五种PWM控制方式下的电流拖尾现象

基于12/8极转子斜槽式双凸极永磁电机,简要介绍了其基本工作原理,然后分别在五种基本的PWM控制方式下,对一周期每工作区间内关断相绕组的工作情况进行了研究.研究表明,除PWM双斩控制方式外,其余四种PWM单斩控制方式下,均会在关断相绕组中出现一类特殊的电流拖尾现象.本文对电流拖尾产生机理进行了详细推导和阐述,给出了不同PWM控制方式下绕组电流的典型波形及分析,探讨了电流拖尾对电机运行的影响.基于四种PWM单斩方式下电流拖尾产生机理的相似性,文末以单斩桥臂上管的H_pwm-L_on型控制方式为例,给出相关实验结果,验证了理论分析及结论的正确性.

Mechanism of Current Lag Under Five PWM Control Strategies in Doubly Salient Permanent Magnet Motors

For a 9kW, 12/8-pole skewed slot doubly salient permanent magnet motor, working principle of its three-phase full-bridge power inverter is first described, then five basic PWM control strategies are discussed. Theoretical analysis reveals that under four kinds of single-chopping PWM control strategies, non-conducting winding that should have no current appears special current lag for every working region. The mechanism of the current lag is deduced, which is quite different from chopping current and winding current during commutation. Based on above analysis, typical winding currents under five basic PWM control strategies are given. Also, the influence of current lag on motor performance is illustrated, including torque output, and torque ripple. Finally, experimental results under H_pwm-L_on control strategy are given to verify the correctness of the analysis.