Comparison of Two Different Interior Permanent Magnet Type Low-speed Rotor Structures of Axial-Flux Magnetic Gear

Abstract

Magnetic gears have beneficial features such as low vibration and maintenance-free owing to no mechanical contacts. Among the several types of the magnetic gears, a flux-modulated type magnetic gear has a higher torque density than the other types. Thus, it is expected to be put into practical use. Previous studies have verified that an interior permanent magnet (IPM) structure rotor can reduce the eddy current loss in magnets. In this study, IPM rotor structures proper to a flux-modulated type axial-flux magnetic gear (AFMG) were investigated. Two types of IPM low-speed rotor structures, one is a spoke-shape and the other is a segment-shape, were compared in terms of torque and efficiency. Furthermore, to prove the validity of the proposed rotor structure, prototype tests were conducted.