A NOVEL PM SHAPE for Reducing Cogging Torque in AFPMSM

Torque ripple in electrical machines is an important issue which may cause several problems in use. In permanent magnet machines and machines with DC excitation, main part of torque ripple is because of cogging torque. There are several ways to reduce this torque and in permanent magnet machines, optimized shape of permanent magnets is one of them. In this paper, a novel shape of permanent magnet in an Axial Flux Permanent Magnet Synchronous Machine (AFPMSM) is proposed which reduces the motor cogging torque and hence over come the torque ripple. First, reference motor is designed with conventional PM shape and then novel PM shaped AFPMSM is designed. These two machines are analyzed by MAXWELL software and then their torque ripples are computed. Results show 35 percent reduction of cogging torque.