Influence of slot opening on electromagnetic performances in fractional-slot interior permanent-magnet machines with concentrated windings for EV application

Fractional-slot interior permanent magnet machines with concentrated windings (FSCW-IPM) are more and more popular in electric vehicle researches for their high power density, high torque density and high efficiency. Since FSCW-IPM is sensitive to its structural parameters, this paper focuses on investigating the slot opening influence on electromagnetic performances of FSCW-IPMs, such as the torque density, torque ripple, rotor eddy current loss and overload capability which are key performances for EV electric motors. The optimization process of slot opening is presented with reasonable consideration of the key performances for EV electric motors. In addition, the tip thickness is optimized to maximize the torque density. This paper gives insight into the influence of slot opening and tips on the performance of FWCW-IPMs.