Design and analysis of a novel axial actively regulated slotless skew winding bearingless motor

This paper presents a novel axial actively regulated slotless skew winding bearingless motor (SSWBM), which features the toroidal skew winding. This motor can generate both torque and axial suspension force with only q-axis current which can reduce the demagnetization risk compared with the state-of-the-art single-drive/one-axis actively regulated bearingless motor utilizing field weakening and strengthening effect of d-axis current. The axial motion of the rotor is actively regulated and radial and tilting motions are passively stabilized by the repulsive type radial passive magnetic bearing (RPMB). Slotless topology is adopted to promise low losses due to the lack of field fluctuations in the rotor as well as a compact design. Therefore, the SSWBM has the advantages of simple control method, hard demagnetization, and low losses. In this paper, the structure and principle is introduced. The finite element model (FEM) analysis is carried out and simulation results have demonstrated the feasibility of the novel proposed axial actively regulated slotless skew winding bearingless motor.