A novel magnetic gear for high speed motor system

In the industrial field, the drive system integrated the high speed motor and the gear is required to effectively utilize the limited space. However, mechanical gears often require their lubrication and cooling, they generate whilst noise and vibration. To overcome these problems, the magnetic gears have been expected. Magnetic gears achieve the system with maintenance-free, low noise and low vibration characteristics by contact-less power transformation. However, conventional magnetic gears are not suitable system for high speed motors because the mechanical strength is weak due to permanent magnets of the high speed rotor. This paper presents a novel reluctance magnetic gear and flux switching magnetic gear for the super high speed motor. The high speed rotor of the proposed magnetic gears is constructed by only iron core. Therefore, the structure is very simple and robust and it is possible to rotate in the high speed region. Moreover, the reluctance magnetic gear realizes high efficiency compared with the conventional surface permanent magnet (SPM) magnetic gear because the magnet eddy current loss on high speed rotor is not generated. While, the flux switching magnetic gear realizes the high torque density by utilizing the magnetomotive force of stationary field magnets. In this paper, the performances of these proposed magnetic gears including torque density, the system size, loss and efficiency are evaluated.