车用永磁轮毂电机解析建模与齿槽转矩削弱
Analytical Modeling and Cogging Torque Weakening of Permanent Magnet In？？Wheel Motor for Electric Vehicles

为了提高永磁电机设计和优化的效率,避免有限元软件建模、计算耗时长的缺点,建立了定子齿上开有辅助槽的表贴式永磁电机的解析模型。在二维极坐标下以矢量磁位为位函数,在各个子域建立拉普拉斯方程或泊松方程,根据分离变量法求解各子域矢量磁位的表达式,并利用各子域的边界条件求得相关的谐波系数,推导了该永磁电机模型空载下的气隙磁通密度、齿槽转矩、磁链和反电动势公式。然后,计算了一台车用轮毂外转子32极48槽永磁电机在空载下的气隙磁通密度、齿槽转矩、磁链和反电动势,并通过有限元法和齿槽转矩实验验证了解析模型的有效性和精确性。此外,基于解析模型优化了该轮毂电机的齿槽转矩,将齿槽转矩削弱了37.2％。
To improve the efficiency of design and optimization of permanent magnet motors and avoid lengthy finite element modeling and computing time, an analytical model of surface？？mounted permanent magnet motor with auxiliary slots is built. The Laplace equations or Poisson equations are established in each subdomain with the vector magnetic bit as a function in the two？？dimensional polar coordinates, and the vector magnetic bit expression of each subdomain is solved according to the separation variable method. The relevant harmonic coefficients are obtained using the boundary conditions of each subdomain. The air gap flux density, cogging torque, flux linkage and back？？electromotive force(EMF) of the model are deduced under no？？load condition, then the air gap flux density, cogging torque, flux linkage and EMF of a 32？？pole？？48？？slot external rotor in？？wheel permanent magnet motor used for electric vehicles are calculated under no？？load condition. The accuracy and validity of the analytical model are verified by finite element method and cogging torque experiment. In addition, the cogging torque of the in？？wheel motor is optimized on the basis of this analytical model, and is consequently reduced by 37.2％