Design and Optimization of Different Integrated Bearingless Motor Topologies for Magnetic-Geared Motors

Magnetic-geared motors have many advantages over mechanical gearboxes, such as reduced maintenance and overload protection. However, the limited life of the mechanical bearings, which hold a high-speed rotor, is problematic in terms of durability. In this paper, a magnetic-geared motor with an integrated bearingless high-speed rotor having a novel structure is proposed to solve this problem. The proposed magnetic-geared motor has an additional three-phase winding to achieve magnetic suspension for the high-speed rotor. In addition, the proposed structure has a consequent-pole high-speed rotor for simplified suspension control, and it can reduce the number of sensors. This paper presents the principles of magnetic suspension and torque generation. In addition, a comparison of the magnetic suspension characteristics and torque capabilities of different motor topologies determined by finite element analysis is discussed.