Influence of pole and slot combinations on cogging torque in fractional slot PM motors

Abstract This paper investigates the influence of the pole and slot combinations on cogging torque for motors with a number of slots per pole per phase between 1/2 and 1/4. Criteria for selecting the motor with the lowest cogging torque among any valid pole and slot combinations are proposed. A technique for reducing cogging torque in surface-mounted permanent magnet motors is also presented. The finite-element analysis method is used for the calculation of the cogging torque.