Research on Air Gap Magnetic Field Model of Permanent Magnet Spherical Motor with Armature Reaction

With the development of permanent magnet spherical motor (PMSM), it is important to analyze the air gap magnetic field quickly and accurately. The result of finite element model shows that the harmonic content is increased and complicated when there is armature reaction in motor, which makes it more difficult to analyze the air gap magnetic field. Therefore, this paper first proposed an equivalent model of PMSM’s stator coils based on Euler angle matrix to unified the model forms of the two magnetic sources in PMSM; Then the analytical model of air gap magnetic field based on spherical harmonic function is established and its harmonic composition is analyzed; Finally, compared with the simulation results of finite element model, the difference of the fundamental and main harmonics between the two models is about 10%, proving the effectiveness of the proposed method.