PERMANENT-MAGNET SYNCHRONOUS MOTOR

摘要

Provided is a permanent-magnet synchronous motor whereby a 12f component of torque ripple can be minimized when using a radial anisotropic ring magnet in a small-diameter motor. Said synchronous motor has Z annular stators with wire windings and a permanent magnet with 2P poles, Z/(3·2P) being either 2/5 or 2/7 (3 being the number of phases). If a radial anisotropic ring magnet is used as the permanent magnet, a 12f component of torque ripple can be minimized by magnetizing the radial anisotropic ring magnet such that the ratio of a flat region to a transition region in the magnetization waveform of one magnetic pole has an appropriate value given tw/h, where h is the tip width of flange parts constituting the tip sections of the stators and tw is the base width of said flange parts.