Demonstration of Ultra-High-Speed Magnetic Gear

In recent years, electrification has rapidly advanced in various fields toward realizing a decarbonized society, and the performance improvement of electric motors is strongly required. The development of high-speed motors over 50,000 rpm has been desired to reduce the size and weight and increase the power density. Magnetic gears can change speed and torque without mechanical contact. Thus, they have low vibration, acoustic noise, wear, and friction heating. These features are desirable for high-speed applications. Among various types of magnetic gears, a flux-modulated type magnetic gear has larger torque. This paper describes an ultra-high-speed flux-modulated type magnetic gear that can operate at 80,000 rpm and has a high-power density. The prototype test results show that the maximum efficiency of the prototype magnetic gear is 94.9% in the low-speed region, and 85% even at 80,000 rpm. Moreover, the power density of the prototype magnetic gear achieves about 4.5 kW/kg.