Establishing the Power Factor Limitations for Synchronous Reluctance Machines

This paper discusses a goodness index and introduces a badness factor for electric machines with a special reference to synchronous reluctance motors. This factor is then used in conjunction with a computationally efficient finite-element electromagnetic analysis and a differential evolution optimization algorithm in order to carry out a large-scale design study under comparable specifications with an induction motor. It is shown that for synchronous reluctance machines, careful rotor geometry optimization can improve the performance, and that the inherent limitations, including those for the power factor, can be systematically established. The correlations for specific average torque, copper and core losses, and efficiency are also discussed.