Investigation of Torque Dependence of Losses in Flux-Modulated-type Magnetic Gear

Abstract

  In recent years, there has been a strong demand for electric motors to be reduced in size and weight and increased their output power density by increasing the rotational speed over tens of thousands of rpm. However, it is challenging to realize mechanical gears that can operate at such ultra-high speed due to mechanical contact. Magnetic gears have been getting attention recently because they can change speed and torque without mechanical contact. Thus, they have low vibration, noise, wear, and friction heating. These features are desirable for ultra-high-speed applications. In particular, a flux-modulated-type magnetic gear is expected to be put into practical use because it has a higher torque density than other kinds of magnetic gears. However, the torque dependence of losses is not fully clarified yet. In this paper, the torque dependence of losses in the prototype magnetic gear is clarified by experiment and finite element method (FEM), and the influence of pole-pairs, an important parameter in determining the gear ratio of magnetic gears, is discussed.