Synchronous reluctance motors with asymmetric rotor shapes and epoxy resin for electric vehicles

This paper deals with the design of a Synchronous Reluctance motor for full-electric vehicle applications. In particular, the design is focused on premium vehicles and aims at the development of rare-earth free electric motor technologies featuring low cost manufacturing. Different solutions are proposed and compared with focus on the rotor design; the investigated topologies employ asymmetric rotor structures with fluid shaped barriers without radial ribs to maximize the average torque and minimize the torque ripple. As this choice is very critical for the mechanical strength of the rotor core at high speed, it has been decided to fill the flux barriers with epoxy adhesive resin. The use of the resin has required an accurate mechanical analysis in order to assess the rotor robustness at high speed.The paper presents the performances of the optimized design and the efficiency and torque ripple maps: moreover, useful information on the use of the epoxy resin in the synchronous reluctance motor are provided.