Demagnetization Analysis of Surface-Mounted Permanent-Magnet Synchronous Machine Based on Subdomain Model

We present a model of demagnetization of surface-mounted permanent-magnet (PM) machines (SMPMMs) based on a subdomain model. The PM volume demagnetization percentage is calculated at different current densities and rotation angles. In this research, we study the demagnetization error as a function of the size of the matrix resulting from the subdomain model and the finite element method (FEM) to evaluate the advantage of the subdomain model in terms of computational resources. In our machine, compared with the FEM, the matrix size decreases by 15 times and the average error of the subdomain model is less than 1.2%. The subdomain model is hence a helpful tool for quick preoptimization of SMPMMs.