用“软铁磁极”减少永磁电机齿槽转矩的方法
Cogging Torque Reduction for SPMSM by Using a“Soft Iron Pole”

针对表贴式永磁同步电机存在齿槽转矩不易削弱的问题，提出了一种采用“软铁磁极”结构降低齿槽转矩的新方法．阐述降低齿槽转矩的基本原理，并通过数学推导给出了齿槽转矩优化效果与“软铁磁极”宽度选择的一般规律．与同结构采用偏极的方法以及采用斜槽的方法进行仿真对比，针对它们的反电动势、磁通密度分布、齿槽转矩等不同方面进行仿真分析新方法所具有的优势，同时通过样机实验验证结论．结果表明，样机采用“软铁磁极”的方法时，在选取3mm“软铁”宽度时对削弱效果最好的齿槽转矩为30mN？m．
A“soft iron pole”structure was proposed in this paper to reduce the cogging torque in the surface mounted permanent magnet synchronous motor(SPMSM). The basic principle of its optimization was introduced. The best optimized results and general parameter selection rule of width of“soft iron pole”were summed up through mathematical deduction. The correction of this method was verified with finite element method(FEM). A polarization motor and a motor with skew slot were taken as references to simulate with FEM and the advantages of“soft iron pole”structure were analyzed in terms of back electromotive force(back-EMF)，magnetic density distribution， cogging torque and so on. The conclusion was verified through experiments. It is shown that the prototype motor with the“soft iron pole”structure can reduce the cogging torque to only 30mN？m while its width is 3mm