Development of a Consequent Pole PM Type Axial-Gap Motor with DC Field Winding

Permanent magnet synchronous motors (PMSM) for electric vehicles (EV) requires three properties; high torque, high efficiency at low torque region, and constant output in wide speed range. However, these have a relation of a trade-off at magnitude of field magnetic flux. In this paper, consequent pole PM type axial-gap motor with the ferrite PMs and the field windings, which has structure variable field magnetic flux, is introduced. Also, in order to examine operation characteristics of the proposed motor, a prototype is produced and tested. Experimental results show that the proposed structure is effective in realizing all of three properties; high torque, high efficiency at low torque region, and constant output in wide speed range.