Influence of magnet shape on torque behavior in surface-mounted permanent magnet motors

This paper discusses influence of magnet shape on torque behavior in surface-mounted permanent magnet (SPM) motors. The effect of pole embrace optimization, magnet-skew and magnet shaping have been analyzed in different 8-pole, 24-slot, three phase SPM motors which having the same stator configuration. Finite-element method (FEM) is used to predict Back-EMF and torque ripple. The result shows magnet-skew can reduce cogging torque efficiently. Magnet sharping with 3rd harmonic increases average torque compared with sine magnet shaping and lower torque ripple compared with magnet-skew with optimized pole embrace.

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