A Novel Magnetic Gear Integrated Segmented Rotor SRM with Reduced Rare-Earth Material

Torque density enhancement of electric motors by magnetic gear integration is becoming increasingly popular. However, the cost and supply of high energy density rare-earth permanent magnets are of concern. This paper investigates the feasibility of integration of reduced permanent magnet (PM) and PM free magnetic gears with high power and/or torque electric motors. Two configurations of a rugged magnetic gear integrated segmented rotor switched reluctance motor (SSRM) topology are proposed for a heavy duty electric truck. In this topology, the saliency of the segmented rotor is exploited on both the sides to seamlessly integrate a reluctance magnetic gear with the motor. With this topology, a magnetic gear can be integrated to a SSRM without any design or structural change of the existing SSRM, which is a unique feature. Both the configurations of the proposed topology are designed and simulated by finite element method for performance evaluation. Feasibility and limitations of the said configurations in high power motoring applications are investigated.