Electrical Parametric Design of Permanent Magnet Machine for High Power Urban Electric Vehicles

This paper proposes a methodology for the selection and parametric design of Permanent Magnet (PM) based Machines for high-performance Electric Vehicle (EV) application. A system-level design approach has been adopted to obtain the desired torque-speed envelope of PM machines based on the vehicle specifications and driving conditions. The electrical machine parameters namely flux linkage and inductances are determined from the desired torque-speed envelope. A minimum limit on the stator resistance per phase is also obtained using the short circuit analysis in generation mode and the demagnetisation characteristics of the PM. The proposed design procedure also provides an inherent selection criterion among Interior Permanent Magnet Synchronous Machines (IPMSM) and Permanent Magnet assisted Synchronous Reluctance Motor (PMaSynRM) for given EV performance specifications. Henceforth, this can form the basis for the selection and electromagnetic design of PM machines. The analytically obtained machine parameters are used to develop a simulation model for the vector control drive of the PM motor and the desired torque-speed envelope is validated.