凸形不等厚磁极永磁电机建模与分析

Modeling and Analysis of Permanent Magnet Machines with Salient Shape Unequal Thickness Magnets

在永磁电机设计中,转子磁极形状对永磁电机的电磁性能产生较大的影响。该文提出两种凸形不等厚磁极的永磁电机,分别为凸半圆形和凸梯形。对这两种凸形不等厚磁极的永磁电机进行建模,采用精确的子域模型方法,通过边界条件求解每个子域中的拉普拉斯方程和准泊松方程,从而得到气隙磁场的解析式,并得到空载感应电动势、电磁转矩以及齿槽转矩等电磁性能参数的解析式。与永磁用量相同的传统表贴式永磁电机相比,结果表明:两种凸形不等厚磁极的永磁电机不仅空载感应电动势基波幅值较高,谐波含量较低,而且电磁转矩较大、齿槽转矩较小。此外,还分析了两种凸形不等厚永磁结构参数对永磁电机电磁性能的影响。最后,利用有限元法对解析模型的正确性进行了验证。

The shape of magnets directly influences the electromagnetic performance of permanent magnet(PM) machines significantly. Two kinds of novel PM machines with salient shape unequal thickness magnets were presented. Two salient shape unequal thickness magnets were modeled. The airgap magnetic field in the machines was analytically obtained by a subdomain model method with solving the Laplacian and quasi-Poissonian equations in each subdomain and applying the boundary conditions. Besides, the back electromotive force(EMF), electromagnetic torque and cogging torque were analytically obtained. Compared with the conventional structure with equal thickness magnets, the machines with salient shape unequal thickness magnets can improve the electromagnetic performance with the equal magnet usage. In addition, the influences of the parameters of salient shapes on the electromagnetic performance were also investigated. Finally, the correctness of the analytical models was verified by a finite element method(FEM).