Eddy current loss calculation model for surface mounted permanent magnet motor under pulse width modulation
To solve the problem that the existing analytical model unable to calculate eddy current loss caused by pulse width modulation,an analytical model was proposed.By using the magnetic permea-bility distribution function to obtain the air gap radial magnetic density,the stator slotting and stator harmonic current could be considered simultaneously.The magnetic density change rate in the perma-nent magnet was calculated while ignoring the eddy current reaction and the finite difference method was applied to calculate the eddy current loss.The accuracy of the model was verified by finite element method(FEM),and it was found that with the increase of the number of permanent magnet seg-ments,the eddy current loss decreases,and the eddy current reaction was weakened.Based on that model,the influence of each current harmonic on the eddy current loss was studied,and the conclu-sion is obtained that the eddy current loss of the permanent magnet is mainly caused by the current harmonic near the switching frequency of 1 and 2 times.
pulse width modulation harmonicseddy current losssurface mounted permanent mag-net motorfinite element method
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