Torque production in permanent-magnet synchronous motors

An analytical method was developed to determine cogging as well as commutating torque in permanent-magnet machines of both buried and surface-mounted magnet types. A detailed analysis of the torque production in a permanent magnet synchronous motor drive with rectangular current excitation is presented. The effect of skewing is considered. The proposed method takes advantage of the knowledge of the flux density distribution in the air gap as a function of design parameters. The equations can be programmed easily and are very useful for parametric studies and optimization.<>