High Speed Synchronous Reluctance Motors for Electric Vehicles: a Focus on Rotor Mechanical Design

This paper deals with the design of high-speed Synchronous Reluctance motors for electric vehicle applications. The need to enhance power density and lowering costs leads to the design of high speed motors with a reduced amount of rare earth. Pure synchronous reluctance motors potentially operate at high speed and exhibit a low cost rotor compared to PM and induction motors. Nevertheless, they present reduced performances in deep flux weakening operations in particular when the so-called radial ribs are introduced to increase the mechanical robustness of the rotor. In this paper the adoption of the radial ribs in the related design challenges are investigated and discussed. The adoption of a suitable commercial optimization tool able to optimize the placement and the sizing of the radial ribs is presented. The approach leads to an original positioning of the radial ribs able to preserve the performances of the motor at high operating speed enhancing the mechanical integrity of the rotor.