Rapid Prediction of Magnetic and Temperature Field Based on Hybrid Subdomain Method and Finite-Difference Method for the Interior Permanent Magnet Synchronous Motor

The solution speed of the finite-element method (FEM) limits the design and analysis of the motors in various physical fields. This article presents a rapid prediction method for the magnetic and temperature field of the U-shaped interior permanent magnet synchronous motor (IPMSM). First, an analytical method combining the magnetomotive force (MMF)-permeance method and the subdomain method is performed to predict the magnetic field distribution. Considering the complex rotor structure, a novel subdivision equivalence method and boundary processing are employed to ensure the minimum loss of shape transformation. It dramatically expands the versatility of the analytical method and has unparalleled computational efficiency. Furthermore, this article introduces an original numerical computing technique to calculate the temperature distribution throughout the motor. The finite-difference method (FDM) is applied to the periodic model, specifically focusing on improving the calculation speed. By classifying the grid points, the temperature distribution can be obtained. The proposed method avoids the limitation of the analytical method in solving the temperature field and offers better computational efficiency than the FEM. Based on these models, the coupling between the two fields is discussed. Finally, a six-pole 36-slot prototype is manufactured. The presented approach is compared with FEM and experiment, demonstrating effectiveness.