分布式驱动用永磁同步电机电磁转矩的解析计算

摘要

针对分布式驱动电动汽车车身阶次振动和车内噪声的主要振源一外转子表贴式永磁同步电机6k阶(k∈N)转矩波动,提出了一种分布式驱动用永磁同步电机电磁转矩的解析计算方法.基于永磁同步电机磁场畸变,对永磁磁极在均匀气隙中的径向分量进行了傅里叶级数分解,通过磁链、电压的计算,最终得到电磁转矩的解析解,为永磁同步电机的阶次振动与振源识别提供了理论基础.当不考虑电流谐波的影响时,对电磁转矩做了阶次分析,论证了由永磁体磁场谐波引起的电磁转矩波动频率是电源频率的6k倍频.最后,通过有限元计算验证了该解析计算结果.%In regard to the 6k order torque ripple of PMSM which causes the body structure vibration and noise in distributed drive electric vehicle, a new calculation method for the electromagnetic torque of PMSM in distributed drive was presented. According to the distortion of field in PMSM, the radial flux density of permanent magnet in uniform air gap was expanded to Fourier series. By means of the calculation of magnetic flux linkage and voltages, an analytic expression of electromagnetic torque was finally obtained. The 6k order (k ∈ N) vibration component of PMSM in distributed drive was explained theoretically. According to the spectrum analysis and order analysis, it proves that the torque ripple frequency tends to be proportional to the number of pole pairs and the rotating speed. The analytic calculation result was tested and verified by means of the finite element method.