Calculation and Analysis on PM Thermal Characteristics Influence Performance of PMSM Based on FEM

Abstract

The irreversible demagnetization of Nd-Fe-B permanent magnet (PM) material appears during the use of Nd-Fe-B permanent magnet synchronous motor (PMSM) has been blocking this kind of motor towards the direction of large-scale. Demagnetization of PM is mainly affected by the working temperature and the reverse magnetic field of stator armature, and the accurate calculation for the demagnetization characteristics of PMSM is usually difficult by using the analytical method. In this paper, we derive the calculation formula of the knee point under a working temperature for permanent magnets in PMSM firstly, then calculate and analyze the demagnetization characteristics of PMSM under different working temperatures and loads by using the Finite Element Method (FEM), Thereby more accurately reflect the working characteristics of PM and the overload capability of motor. This paper provides theoretical basis for the selection of PM materials and the calculation of PM thickness in the PMSM design.