A novel stator structure with soft magnetic composite in one-axis actively positioned single-drive bearingless motor

This paper presents a novel stator structure in 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. Single-drive bearingless motor concept has been adapted. Both torque and active axial force are regulated independently by only one three-phase inverter and one displacement sensor. Only axial z-axis position is actively regulated. The other axes, radial movements and tilting movements, are passively stabilized. A novel stator structure is proposed to increase active axial force. The stator is designed in three-dimensional structure with a soft magnetic composite. A comprehensive voltage equation is derived. As a result, basic equations of the torque and active axial force are presented. In experiment, it is confirmed that the active axial force of the proposed stator structure is enhanced by 39.6 %.