分布式驱动用永磁同步电机电磁转矩的解析计算

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—外转子表贴式永磁同步电机6k阶（ ）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。

Analytical calculation of electromagnetic torque in permanent magnet synchronous machine in distributed drive

for 6k order torque ripple of PMSM which causes the body structure vibration and noise in distributed drive electric vehicle, a new calculation method of the electromagnetic torque for PMSM in distributed drive is presented. According to distortion of field in PMSM, radial flux density of permanent magnet in uniform air gap is expanded to Fourier Series. By means of calculation of magnetic flux linkage and voltages, analytic expression of electromagnetic torque is finally obtained. Therefore, this paper explains in theory 6k order（ ）vibration of PMSM for distributed drive. According to spectrum analysis and order analysis, it proves that torque tipple frequency tends to be proportional to pole pairs and rotate speed. At the last, the analytic calculation result is tested and verified by means of the finite element.