用半解析法计算永磁无刷直流电机齿槽定位转矩

Semi-Analytical Approach for Cogging Torque of Surface Permanent Magnet Brushless Motors

采用半解析法计算表贴式永磁无刷电机的气隙磁场及其齿槽定位转矩。永磁体和气隙区域用解析法求解,槽形区域用差分法计算。两区域共有部分的磁场计算结果可作为另一场域的边界条件。能真实反映气隙磁场的径向分量和切向分量,由此可准确计算定子开槽时的齿槽定位转矩,实例计算与有限元分析结果吻合较好,证明了此方法的正确性。

A semi-analytical approach was applied for cogging torque analysis of surface permanent magnet brushless motors. The field region was divided into permanent magnet,air-gap and slot sub-regions. Permanent magnet and air-gap could be considered as a same region. The semi-analytical method which combines analytical method with finite differential method was applied to calculate this region. The analytical solution was applied to air-gap field equation and permanent magnet field equation while the difference method to solve the field equation in slot region. Two regions had common parts in which each field calculated result could be used as the boundary condition for another. On the effect of stator slot opening in open-circuit air gap field distribution could be individually presented in radial and tangent directions. The proposed approach was exemplified by using practical permanent magnet brushless DC machines and verified by comparing with the finite element method, which proved the proposed method was correct and effective.