Design of multiphase exterior rotor switched reluctance motor for traction applications

Interest in using magnet-less motor such as switched reluctance motors (SRMs) for electric and hybrid electric vehicles (EV/HEVs) continues to gain popularity, owing to their lower costs and robustness. This paper presents design procedures and comparisons between three different multiphase SRMs for a specific traction application using finite elements analysis (FEA). Four-phase, five-phase, and six-phase SRMs have been studied and compared based on the given constrains and conditions. The desired application torque-speed characteristic has been provided in this paper and it is shown that all three designs meet all requirements. By considering just the design aspect, FEA shows that the five-phase SRM is the best candidate for this application, but considering the converter and control complexity the four-phase SRM is selected and was built. The experimental tests were performed for a few operating points of torque-speed characteristic and also the motor phase current and voltage at rated speed are presented.