Design of a permanent magnet motor with SPWM-shaped magnets for an electric scooter

This paper proposes the novel design of a surface-mounted permanent-magnet (SPM) motor with a magnet surface that is a sinusoidal pulse-width-modulation (SPWM) shape for an electric scooter. The optimal SPWM magnet shape on the SPM motor was designed by maximizing the output torque and efficiency and minimizing the magnet volume, and was verified with finite element analysis. The prototype motors were fabricated with magnets of various shapes, with or without an SPWM surface. The experimental results showed that the prototype motors with SPWM-shaped PMs had a high percentage of fundamental harmonics. The amount of rare-earth magnet material used in the motor with SPWM-shaped PMs was less than the amount used in motors without SPWM-shaped PMs.