An Independent Controller Of Radial Force Subsystem For Super-High-Speed Bearingless Induction Motors

The bearingless machines which combine the magnetic bearing and motor, is a great progress in recent years of research field of the high speed electrical machinery. Among them the bearingless induction motor (BLIM) is quite paid attention to because of its capability of easily weakening flux and high reliability. The BLIM is a strong coupled complicated nonlinear system. For the high accuracy requirement for the real-time control of air gap flux linkages, the various decoupling control algorithms can not realize this motor operating at super high speed at present. In this paper, an independent control strategy of radial force subsystem is proposed to realize the super high speed operation of BLIM. The air gap flux linkages of motor windings and radial force windings which are required can be identified accurately by the method of simpler voltage-model, in which the two only motor parameters-stator resistance and stator leakage are estimated by LSE based on zero-sequence voltage equations simultaneously. The current regulated PWM inverter is replaced by the air gap flux linkages regulated PWM inverter to improve control precision of air gap flux linkages. In order to reduce time delay of control system, the control period of radial force subsystem can be shortened to a great extent through right resource distribution in digital control systems.