CORE LOSSES IN PERMANENT-MAGNET MOTORS

The conventional approach to core loss prediction using the Fourier series of the space wave of air gap flux density is not applicable for surface mounted permanent magnet motors. This paper presents an alternate approach based on the concept that eddy current losses are proportional to the square of the time rate of change of flux density. Expressions are derived for predicting hysteresis and eddy current losses in the stator teeth and yoke. Prediction of core losses are compared with losses measured on a 4-pole PM motor confirming the applicability of the proposed approach. © 1990 IEEE