A Novel Stator Structure for Active Axial Force Improvement in a One-Axis Actively Positioned Single-Drive Bearingless Motor

This paper presents a novel stator structure in an actively positioned bearingless motor with 1-degree of freedom. The single-drive bearingless motor concept has been adapted so that the torque and active axial force are regulated independently by the q- and d-axis currents, respectively, with only one three-phase inverter. The axial z-axis position is actively regulated, but the other axes (i.e., the radial and tilting movements) are passively stabilized. A novel stator structure has been proposed to enhance the active axial force. The stator is designed with soft magnetic composites. Experiments confirmed that the active axial force is enhanced by 50%.