LAUSR

This paper presents a novel axial vibration suppression method in two-axis actively positioned permanent magnet bearingless motors. Only radial directions are actively positioned. The axial and tilting directions are passively stabilized by the magnetic attraction force between the stator core and the rotor permanent magnet. Generally, a damping force is considerably low in the axial and tilting directions. Therefore, when an axial disturbance force is applied to the rotor, the axial vibration is generated, and then, the vibration cannot be suppressed at a critical speed. In this paper, a novel axial vibration suppression method by d -axis current is proposed. The damping force is generated by d -axis current regulation. In this proposed method, the rotor axial position is estimated from the flux linkage variation in the motor winding. Therefore, an additional displacement sensor is not necessary. In experiments, it is confirmed that the rotor axial vibration is successfully suppressed by the proposed method.