Comparing Electric Motors: An Analysis Using Four Standard Driving Schedules

Permanent magnets with rare-earth materials are widely used in interior permanent magnet synchronous motors (IPMSMs) in hybrid electric vehicles (HEVs). The recent price increase in rare-earth materials has become a serious concern. A switched reluctance motor (SRM) is one of the candidates for HE V rare-earth-free motors. An SRM has been developed with dimensions, maximum torque, operating area, and maximum efficiency that all compete with the IPMSM. The efficiency map of the designed SRM is different from that of the IPMSM; thus, direct comparisons have been rather difficult. In this article, a comparison of the energy consumption between the SRM and the IPMSM using four standard driving schedules is carried out. In the Highway Fuel Economy Driving Schedule (HWFET) and the New European Driving Cycle (NEDC), the SRM is found to have better efficiency because its efficiency is high at the high rotational speed region.