Comparison of Five Topologies for an Interior Permanent-Magnet Machine for a Hybrid Electric Vehicle

This paper presents a detailed comparison of the characteristics of five different rotor topologies for a distributed winding permanent-magnet (PM) machine for high-performance traction applications, including hybrid electric vehicles. These rotor topologies include one surface PM topology and four single-layer interior PM topologies (conventional, segmented, V shape, and W̅ shape). The performance characteristics, which include the back-electromotive force and its harmonics, magnet mass, iron loss, and ripple torque are compared and analyzed. A 7.5-kW interior permanent-magnetic (IPM) prototype using the conventional rotor topology was tested and the finite-element analysis results were compared. The aim of the paper is to give some guidance and reference for machine designers who are interested in IPM machine selection for high-performance traction applications.