A 2D-3D hybrid FEM approach for fast analysis of eddy current loss in magnets of PMSM driven by a PWM inverter

Abstract

A 2D-3D hybrid finite element method (FEM) approach is proposed for fast analysis of eddy current loss in magnets of permanent magnetic synchronous motors (PMSM) driven by a pulse width modulation (PWM) inverter. A voltage-source PWM inverter circuit coupled 3D FEM model of a PMSM was built with the commercial FEM code JMAG and the eddy current loss in the magnets of the PMSM was calculated which was extremely time-consuming. As the eddy current loss in magnets is relatively small compared with the power capacity of the motor, a voltage-source PWM inverter circuit coupled 2D FEM model is built to calculate the current waveforms ignoring the division of permanent magnets along the axial direction. Applying the calculated current waveforms from the 2D calculation to a current-source circuit coupled 3D FEM model, the eddy current loss in the magnets can be obtained which needs much less computation time. The result is very close to that obtained directly from the voltage-source PWM inverter circuit coupled 3D FEM model.