Electromagnetic–Thermal Coupling Analysis of Permanent Magnet Synchronous Machines for Electric Vehicle Applications Based on Improved ( ) Evolution Strategy

Coupling field analysis is a powerful tool to analyze and calculate electromagnetic and thermal performances of permanent magnet synchronous machines (PMSMs). However, most coupling analysis methods are based on the time-consuming recursive algorithm. To overcome this deficiency, this paper presents an electromagnetic-thermal coupling analysis method of PMSMs by introducing an improved (μ + 1) evolution strategy. Combining electromagnetic finite-element analysis with thermal resistance network, electromagnetic and thermal performances of PMSMs are comparatively studied under different working conditions by this improved coupling analysis method. Furthermore, the losses of PMSMs with skewed-slot stator core are investigated. By comparing with the conventional method, the result shows that the improved coupling analysis method has advantages in the calculation efficiency and accuracy. Finally, experiments are performed on a prototype and the accuracy of the improved coupling analysis method is proved.