Investigation on high-power-density design of small PM motors focusing on air gap configuration

Abstract

This paper describes a case study of high-power-density design of small permanent magnet (PM) motors focusing on their air gap configurations. Two types of the PM motors, i.e., a radial air gap type and an axial air gap type, are comparatively discussed. Comparison between the two types has been conducted from the viewpoints of I-T characteristics, N-T characteristics, efficiency maps, torque ripple characteristics, and so forth. It has been clarified that the axial air gap type has significant advantages to achieve the high-power-density under some limited condition.