Characteristic comparison of PMSM by slot/pole ratio

SPMSM which can realize the high-efficient drive spreads the application field [H. Dohmeki, 2001]. Recently not only steady-state characteristic but also improvement in transient characteristic is required. Especially, the reduction of the torque ripple is indispensable to the smooth rotation. The cogging torque becomes the representative factor, and its minimization is required. By the difference between the slot/pole ratio, the behavior of the cogging torque consisted was examined. The result showed that the slot/pole ratio in which the cogging torque becomes a minimum existed.