永磁轮毂电机磁场解析建模

Exact Analytical Solution of Magnetic Field in Permanent Magnet In-Wheel Motor

利用谐波建模法提出一种可以在永磁电机研究中考虑导磁材料磁导率为有限值的永磁轮毂电机解析模型,分析了电机的电磁性能。在二维极坐标系下,将电机划分为永磁体、气隙、定子齿/槽、定子齿尖/槽开口四个求解域。在各求解域建立泊松方程和拉普拉斯方程,并联立边界条件求得通解中的谐波系数,从而得出各求解域矢量磁位解析表达式。计算了电机气隙磁感应强度、空载反电动势、输出转矩,通过有限元计算和样机实验验证了解析模型的正确性,并利用该模型研究了极弧系数和槽开口宽度对输出转矩的影响规律。

One exact analytical model method for considering the magnetic permeability of magnetically conductive material in a permanent magnetic motor was given by using harmonic modeling, and the electromagnetic performance of the motor was analyzed. In the two-dimensional polar coordinate, the motor was divided into four domains: the permanent magnet, the air gap, the stator tooth/slot and the stator tooth tip/slot opening. The Poisson and Laplace equations were established in each solution domain, and the harmonic coefficients in the general solution were obtained by the boundary conditions, and the analytical expression of vector magnetic potential in each domain was obtained. The electromagnetic performance of air gap magnetic flux density, no-load back EMF, output torque and so on were calculated. The correctness of this analytical model method was verified by comparison with the finite element method and experiment test results.The model was used to study the influence of the pole arc coefficient and slot opening width on the output torque.