Design of a High-Speed Single-Drive Bearingless Motor

This paper presents a novel design of high-speed single-drive bearingless motor. Only axial direction is actively positioned, and then, radial and tilting directions are passively stabilized. The active axial force and rotational torque are generated by d-and q-axis currents, respectively. In order to reduce required d-axis current at start-up, comparisons of the magnetic suspension performances are carried out by 3D-FEM analysis in three structures. In addition, the stator stack length is minimized to reduce the motor volume. Consequently, both a torque density and a power density are enhanced.