基于磁极不对称角度优化的内置式永磁无刷直流电动机齿槽转矩削弱方法

齿槽转矩削弱是永磁电机研究的重点和难点之一。本文基于能量法和傅立叶分解的解析分析法，给出了磁极不对称时内置式永磁无刷直流电动机的齿槽转矩解析表达式，据此研究了磁极不对称对齿槽转矩的影响，在此基础上，提出了使齿槽转矩最小的磁极不对称角度的解析确定方法。由于解析法采用了一些假设，忽略了饱和、漏磁等影响，所得到的磁极不对称角度不是最佳值。为使齿槽转矩最小，将全局优化方法、解析法和有限元相结合，把寻优可行域缩小在解析解附近以减小求解时间，利用全局优化算法和有限元进行优化，以获得磁极不对称角度最优解。本文对每极槽数为整数和分数的两台无刷直流电动机分别进行了解析分析和优化，结果表明，该文的优化方法可显著削弱齿槽转矩。

Optimization for the Asymmetric Angles of Magnetic Pole to Reduce Cogging Torque in Inner-buried PM Brushless DC Motors

Cogging torque is one of the main concerns of permanent magnet motor. In this paper, to reduce cogging torque in inner-buried permanent magenet brushless DC Motors, analytical method, which was based on energy method and Fourier expansion, was proposed to obtain the expression of cogging torque with magnetic pole asymmetry. Based on the expression, the effect of magnetic pole shifting on cogging torque was studied. The method for reducing cogging torque by suitable selection of magnetic pole asymmetric angles was proposed. As a result of many assumptions which ignores saturation and flux leakage there were errors in the above method. To minimize the cogging torque, a global optimization algorithm (zooming algorithm) and the finite element method(FEM) were combined to find the best magnetic pole asymmetric angles with the shorten feasible region decided by analytical method . Two motors were analyzed and optimized with the above method and the results show that the cogging torque can be reduced notably.