永磁直线电机端部效应力的解析计算

Analytical Calculation for End Effect Forces in Permanent Magnet Linear Motors

短初级型永磁直线电机的纵向端部效应带来了较大的detent force和法向力波动,恶化了其伺服运行性能。为分析电枢电流为零时端部效应力的特点,文章提出了基于磁通的虚位移原理分析端部效应力的方法。在分析纵向端部边缘磁通变化规律基础上,采用虚位移法推导了端部效应引起的法向力波动和推力波动的解析表达式,揭示端部效应力的波动规律。通过对端部效应力解析表达式的分析,归纳总结了动子长度参数对端部效应力的影响规律。最后,对一台12槽11极电机进行了仿真与实验,仿真、实验结果与解析结果基本一致,验证了基于磁通虚位移法分析端部效应力方法的正确性。

The longitudinal end effect of short primary permanent magnet linear motors brings a great detent force and the normal force fluctuation, and aggravates the servo performances. In order to analyze the features of the end effect force when the armature current is zero, this article proposed a method to analyze the end effect force based on the virtual displacement principle combined with the flux function. On the base of analyzing the changes of flux distribution on the longitudinal end face of the mover, the article used virtual displacement principle to deduce analytical expression of normal force fluctuation and the thrust ripple which was caused by end effects, and revealed the fluctuation law of the end effect force. Through analyzing the analytical expressions of the end effect force, the influence law of mover length on the end effect force was summarized. Finally, simulations and experiments were conducted on a 12 slot 11 pole motor, simulation and experimental results are basically consistent with the analytical results, which verifies the correctness of the method to analyze the end effect force based on the virtual displacement principle combined with the flux function.