Improved Accurate Subdomain Model for Magnetic Field Analysis of Surface-Mounted PMSMs with Modular Stator Cores Considering Tooth-tips Saturation Effect and Assembly Clearance

This paper proposes an improved accurate subdomain model for magnet field analysis of surface-mounted permanent magnet motors considering the assembly clearance between modular stator cores and tooth-tips saturation effect. Based on the principle of area equivalence, the improved model incorporates the assembly clearance as an additional subdomain within the traditional model. Then, the relationship between the size of the assembly clearance and the harmonic distortion (THD) rate and amplitude of the back electromotive force (EMF) is studied. Particularly, the proposed model equates the tooth-tips saturation effect to an increase in the effective slot opening width angle. Finally, a 16-pole 18-slot prototype is manufactured and tested. The effectiveness of the proposed analytical model is validated by both the nonlinear finite element method (FEM) and experiment. Compared with the traditional analytical model, the computation errors of the proposed model in terms of back EMF and electromagnetic torque are reduced by about 3%.