A decoupling method for current regulation in bearingless motors using AC suspension current

This paper introduces a novel decoupling method for current regulation in high-speed bearingless motors using AC suspension current. The frequency of the suspension current increases in proportion to rotating speed in the bearingless motors using AC suspension current, and regulating the suspension current is difficult at high speeds rotation. In previous research, a current regulation method is used that convert AC to DC using a rotating coordinate system. However, that method has interference voltages which make the system unstable. In this paper, we propose a novel decoupling method for the suspension current regulation. In the experiment, stable levitation of the bearingless motor is achieved at 30000 min^-1 by using the proposed decoupling controller.