Development of high torque density axial-gap switched reluctance motor for in-wheel direct-drive EV

Switched reluctance (SR) motors attract attention as a machine without rare-earth materials. And it is a candidate technology for electric vehicle application. However, torque density of SR motors is smaller than that of Permanent Magnet Synchronous Machines (PMSMs). Recently, an axial-gap structure is attention on possibility of effective utilization of in-wheel flat motor space. In the paper, a new flat volume axial-gap SR motor as high torque density for in-wheel direct-drive EV is designed. The characteristics of the proto-type machines are measured and compared with FEA results. The characteristics agree with simulation results. Finally, the proto-type machines are mounted on an 8-passenger 2,000 kg vehicle like small bus. The test drive of the in-wheel direct-drive axial gap SR motor vehicle is succeeded.