I. Introduction
High-speed permanent magnet synchronous motors (PMSMs) have outstanding advantages such as high power density, high efficiency, and good control characteristics, and have been widely used in electric drive systems [1]. In recent years, there has been an increasing focus within the research community on PMSMs with fractional-slot concentrated-winding (FSCW) stators because of their easy manufacturability, wide constant power speed range, and low torque ripple [2]. Furthermore, the configuration of FSCW with tooth-wound coils is more conducive to improving volumetric power density because of shorter end winding [3].