组合磁化无槽永磁电机磁场分析与优化研究

Magnetic field analysis and optimization of slotless permanent magnet machines with combined magnetization

永磁电机气隙磁场分布与采用的磁化方式密切相关,设计永磁的磁化类型是电机磁场分析的重要环节。在传统永磁电机采用常规单一充磁类型的基础上,提出由不同磁化方式组合后形成一种崭新的混合磁化方式。首先,采用二维解析法,通过求解拉普拉斯方程和准泊松方程,并依据磁场的边界条件,获得无槽永磁电机的空载气隙磁密精确解析式。然后,利用解析法快速计算的特点,在保证永磁体每极磁化区域单位体积平均剩磁相同的前提下,分析两种组合磁化方式的气隙磁场分布。接着,对永磁厚度进行优化分析。通过计算得出,组合磁化方式可增加气隙磁密径向分量基波幅值,降低气隙磁密中谐波成分,同时能够减小永磁体积,降低电机制造成本。最后,二维有限元法与二维解析法计算结果的一致性,验证了组合磁化解析模型的准确性。

Air-gap magnetic field distribution in the permanent magnet( PM) machines is closely related to the magnetization mode. Selecting a reasonable magnetization mode is of great significance to improve the magnetic field distribution. Based on the analysis of the single magnetization mode,proposing a new hybrid magnetization method formed by combining different magnetization methods. First,the no-load airgap flux density was analytically derived by solving Laplacian and quasi-Poissonian equations and applying the boundary conditions. Second,considering the analytical method with the advantage of little computation time,the air-gap magnetic field was analyzed for two kinds of combined magnetization in terms of the equal average magnet remanence per unit volume in one pole magnetization region. Third,the PM thickness optimization was performed and the optimization results show that the combined magnetization can improve the air-gap flux density and decrease the PM material and the manufacture cost. Finally,the results by the two-dimensional( 2-D) finite element method are in accordance with those by the 2-D analytical models.