An Optimal Design Method for the Minimization of Cogging Torques of a Permanent Magnet Motor Using FEM and Genetic Algorithm

Uneven distribution of permanent magnets (PM) is an effective way to minimize the cogging torques of PM motors. In this paper a novel and efficient finite element method (FEM) is proposed to calculate the cogging torque of PM motors when the PM distribution is uneven. With the proposed algorithm, the computing time required to solving the cogging torque problem is significantly reduced to only 0.06% of that required by using general FEM. Because of the significant reduction in computing time on performance computation of PM motors, it now becomes feasible to use genetic algorithm (GA) to optimize the distribution of the PMs and hence minimizing the cogging torque of the motor.