Analysis and basic design of the magnetically levitated motor with five actively controlled degrees of freedom

Abstract

A magnetically levitated motor can realize non-contact support and rotation of the rotor using magnetic force. Therefore, it has many advantages over conventional mechanical bearings. This paper proposed new magnetically levitated motor (Maglev motor). The proposed maglev motor uses a radial bearingless motor to control both of radial translation (x and y) motion and rotation (θz), and axial magnetic bearings to control both of axial translation (z) and tilt motion (θx and θy). Moreover, stators were installed on the inner side of the rotor, such that the flux path of the axial magnetic bearing and radial bearingless motor are partially-shared. Therefore, the proposed magnetic levitated motor is small, while achieving five degrees of freedom active control. The prototype machine was designed using FEM magnetic analysis. According to this analysis, the device had sufficient magnetic force to control the rotor within a designed airgap. In addition, axial directional dynamic characteristics were measured.