Structure and Principle in a Novel compact One-Axis Actively Positioned Single-Drive Bearingless Motor

Abstract

This paper presents a novel one degree-of-freedom (1DOF) actively positioned bearingless motor. The advantages of the proposed bearingless motor are a compact axial length and high radial stiffness compared with conventional 1DOF bearingless motors. In the proposed bearingless motor, single-drive bearingless motor (SDBM) concept has been adapted. Both torque and axial suspension force are regulated independently by only one three-phase inverter and one displacement sensor. Therefore, the single-drive bearingless motor is low cost and small size. Only axial direction z-axis is actively positioned. The other axes, radial movements x and y, and tilting movements θ_x and θ_y, are passively stabilized. In this paper, a structure and principle of the active axial force generation in a novel bearingless motor are presented.