Design and torque optimization of a PM Synchronous Motor, using an auxiliary winding

Permanent Magnet Synchronous Motors play an important role in performing mechanical torque for propulsion systems and hybrid vehicles. Although the quality of the generated torque is an important issue. Torque fluctuation is a critical problem and should be taken into account in the procedure of designing an electric machine. Several methods and design specifications have been introduced in papers to deal with the problem. In this paper a new method is presented in order to reduce torque fluctuation specially caused by cogging torque. The method is based on application of an auxiliary winding, specifically designated to reduce the cogging torque. The auxiliary winding is placed into stator slots and supplied from a different source. The proposed model is simulated and validated by FEM and two types of results are shown for two different types of stator slots. The application of such winding shows a significant effect on the motor torque quality in both cases.