Application of Epoxy Resin in Synchronous Reluctance Motors with Fluid-Shaped Barriers for E-Mobility

This article deals with the design of a synchronous reluctance (SynRel) 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 requires accurate mechanical analysis in order to assess the rotor robustness at high speed. The article presents the performance of optimized designs without radial ribs and it is focused on the identification of the best properties for an epoxy resin able to enhance the mechanical integrity of the rotor. Moreover, experimental tests on resin cylinder samples have been carried out in order to verify the contact pressure between the resin and a laminated core. The results of this study could be a useful guideline for the designers interested in using this technology for high speed SynRel motors.