偏心条件下轴向磁通轮毂电机不平衡弯矩建模与分析

为了分析静态偏心和动态偏心对轴向磁通轮毂电机的影响,首先建立了未偏心时轴向磁通电机气隙磁场的准3D解析模型,该模型分别通过复数相对气隙磁导和径向修正函数考虑了开槽和边缘效应对气隙磁场的影响;然后通过分析静态偏心和动态偏心时气隙长度随时间和空间的变化,建立了偏心条件下轴向磁通电机的气隙磁场解析模型,有限元结果表明该模型可以准确预测偏心条件下任意位置的气隙磁通密度;最后根据该模型分析了偏心对轴向电机气隙磁场和电磁力的影响,提出了计算不平衡弯矩的方法。结果表明:不同于径向电机,偏心除了产生不平衡磁拉力,还会使轴向磁通电机产生与旋转方向正交的弯矩,该弯矩有导致偏心进一步加剧的趋势。

Modeling and Analysis of Unbalanced Moment for an Axial-Flux in-Wheel Motor with Eccentricity

In order to analyze the impact of static and dynamic eccentricity, a quasi-3D analytical model of air-gap magnetic field was firstly built for an axial-flux in-wheel motor (AFWM) without eccentricity, and the slotting effect and fringing effect was taken into account through complex relative air-gap permeance and correction function respectively. Then the analytical model under eccentric condition was gained by means of considering the variation of air gap length, and finite element (FE) analysis results indicate that the model can predict air gap flux density precisely at arbitrary position of the AFWM with both static and dynamic eccentricity. Finally, the effects of eccentricity on magnetic field and electromagnetic force were analyzed via the established model and the method to calculate bending moment was proposed. The results reveal that apart from unbalanced magnetic pull, eccentricity in AFWM will produce extra bending moment, which is quite different from radial-flux motor. The bending moment may cause eccentric degree further deterioration.