This paper investigated the influence of two typical manufacturing tolerances on electromagnetic performance in interior permanent magnet (IPM) machines.Exemplified by a 12-slot/8-pole IPM machine,modern manufacturing techniques were firstly introduced and the machine performance under ideal conditions was obtained by the finite element (FE) method.With the tolerances of PM diversity and tooth-bulges considered,lower orders of additional cogging torque components were introduced,which could not be effectively reduced by the step-skew methods.To identify the most sensitive cases of different tolerances and evaluate the maximum additional cogging torques,a vector diagram method was proposed,with the effectiveness verified by FE analyses.In addition to the cogging torque,the back electromotive force (EMF) and rated torque were also investigated and compared accounting for the aforementioned most sensitive cases.Finally,prototypes were fabricated and tested to verify the additional cogging torques.%针对内置式永磁电机生产过程中2种典型的工艺误差,研究了它对电机主要电磁性能的影响.以12槽8极设计为例,首先介绍了定转子的生产工艺,并通过有限元方法计算出理想情况下的电机性能.由于永磁体的不一致性和定子铁心内圆度偏差的存在,在齿槽转矩中引入了低阶次的附加谐波成分,无法通过传统的分段斜极方式削除.进一步,用一种向量图的方法,来明确上述工艺误差最敏感的分布以及所引入的附加齿槽转矩最大值,并通过有限元进行验证.此外,还分析了上述误差分布对反电势和电磁转矩性能的影响.最后,制作了样机并进行试验验证.
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