Behavior Modeling and Design of Winding-Switching Permanent Magnet Synchronous Machine System Based on Normalized Model

Due to the advantages of high torque density and efficiency, permanent magnet synchronous machine (PMSM) systems are widely used in electric vehicles. However, the torque capacity and speed range of the PMSM systems might be contradictory under the voltage and current limits. Compared with the PMSM system equipped with a transmission, the winding-switching PMSM system would be one of the solutions to gain large torque capacity and wide speed range at the same time eliminating mechanical problems. For a better design of the torque-speed characteristics of the winding-switching PMSM system, a normalized model is proposed in this paper using two dimensionless parameters, i.e. saliency ratio and normalized characteristic current, and the appropriate design space of these parameters could be given. Simulation and experiment at the turning speeds verify the effectiveness of the proposed model.