Abstract: In response to the problem of air gap eccentricity caused by external disturbances such as road excitation and emergency braking during the operation of electric vehicles, which affeced the normal operation of the wheel switched reluctance motor (SRM), the radial magnetic force at different obtained on the stator surface of SRM was firstly determined on the basis of Maxwell stress tensor method. The variation characteristics of radial electromagnetic force and electromagnetic torque under different air gap eccentricity and different angles were analyzed, and the influence rule of air gap eccentricity on the above two was revealed under transient conditions. It was clarified that air gap eccentricity not only increased radial electromagnetic force but also significantly amplified motor torque fluctuations. Secondly, by analyzing the distribution of magnetic flux density in the stator and rotor, it was clear that the width of the stator and rotor salient poles was the main factor affecting radial electromagnetic force and electromagnetic torque. Lastly, the fluctuations of radial electromagnetic force and electromagnetic torque were suppressed through multi-objective optimization of structural parameters, which were reduced by 15.4% and 24.9% respectively. The optimization scheme was improved under different air gap eccentricities.

Key words: vehicle engineering; air gap eccentricity; radial magnetic force; electromagnetic torque; multi-objective optimization

摘要： 针对轮毂开关磁阻电机在电动汽车行驶过程中，因路面激励、紧急制动等外界扰动造成电机产生气隙偏心，进而影响电机正常运行的问题，首先，基于麦克斯韦应力张量法，获取开关磁阻电机定子表面不同位置处的径向电磁力，分析不同气隙偏心量与不同角度下径向电磁力和电磁转矩变化特性，揭示瞬态工况下气隙偏心对二者的影响规律。明确了气隙偏心不仅导致径向电磁力增大，还显著增大电机转矩波动；其次，通过分析定、转子磁通密度分布情况，明晰定、转子凸极宽度是影响径向电磁力和电磁转矩的主要因素；最后，通过结构参数多目标优化，使径向电磁力和电磁转矩的波动得到抑制，其分别降低15.4%和24.9%，且优化方案在不同气隙偏心量下均得到改善。

关键词: 车辆工程；气隙偏心；径向电磁力；电磁转矩；多目标优化