Torque Density and Efficiency Improvements of a Switched Reluctance Motor Without Rare-Earth Material for Hybrid Vehicles

A machine design of a switched reluctance motor having competitive torque and efficiency as well as compactness with respect to an interior permanent-magnet (IPM) synchronous motor (IPMSM) in a hybrid electric vehicle (Toyota Prius 2003) has been investigated. A torque of 400 N·m is set as a target with an outer diameter of 269 mm with an axial length of 156 mm, including coil end lengths. In addition, a 50-kW field weakening capability must be competitive to the IPMSM. The highest efficiency of 95% is also aimed. Stator and rotor structures and iron material are investigated. Test machines are built. Static and light load tests are carried out.