A permanent-magnet machine with improved torque density based on a single layer winding layout for electric vehicle applications

This paper proposes a novel single layer winding layout for a permanent magnet machine with improved torque density for electric vehicle applications. In this paper, two permanent-magnet (PM) machines with outer rotors and single layer fractional slot concentrated windings are compared based on two different slot/pole combinations, namely 20 slots/18 poles and 20 slots/22 poles. The two machines are inherently five-phase machines; however, a winding layout is employed to create three-phase stator terminals. Hence, the proposed machines exploit the advantages of multiphase machines while providing three phase terminals allowing for standard three-phase converters. Two machines are designed with same rotor and stator dimensions and same stator winding layout but with different number of rotor poles. The comparison is carried out using finite element analysis.