Prediction of 3-D High-Frequency Eddy Current Loss in Rotor Magnets of SPM Machines

This paper proposes a computationally efficient method for accurate prediction of 3-D high-frequency eddy current loss in the rotor magnets of surface mounted permanent magnet machines, employing the imaging method. 2-D finite element analysis (FEA) is used to generate the information on radial and tangential 2-D magnetic field variations (eddy current sources) within the magnet. The diffusion of eddy current sources along the axial plane of the magnet computed analytically is incorporated in the imaging method to establish the 3-D eddy current source variations within the magnet. The modified method is validated with results from 3-D time-stepped FEA for an 8-pole, 18-slot permanent magnet machine, evaluating its magnet loss considering axial and circumferential segmentation.