Effect of change in pole shape design on harmonic contents of PM synchronous motor air gap flux density waveform

This paper utilizes the wavelet packet transform to study the effects of change in the shape of the magnetic pole on the harmonic behavior of air gap flux density waveform. A surface mounted PM motor is used as an example. The original design contains 6 PM poles and 36 stator slots. The rotor and the stator winding are redesigned to have 4, 8, and 12 poles. The air gap flux density waveform is obtained from the finite element solutions. The results have been compared with different pole structure design. It has been found that there is not much difference in the harmonic content due to change in PM pole structure on the air gap flux density waveform.