Study on abnormal power failure shutdown control of magnetic suspension centrifugal compressor

Abstract

Abstract The rotor of a magnetic suspension centrifugal compressor is supported by magnetic bearing, and a power failure will cause the high‐speed rotor to fall directly onto the protective bearings, affecting the reliability of the compressor. To solve this problem, this paper proposes an abnormal power failure shutdown control method with semi‐switching modulation of the inverter. Firstly, the overall scheme of abnormal power failure shutdown control is designed, and its feasibility is analysed in detail through mathematical modelling. Secondly, aiming at the non‐linear, time‐varying and gain uncertainty characteristics of the control system, a voltage control strategy based on parametric self‐regulating sliding‐mode variable structure is proposed, and the stability is analysed. Finally, the method proposed in this paper is experimentally verified, the results show that this method does not depend on the electric angle of the motor compared to existing methods, and the rotor can achieve a zero‐drop speed shutdown, which greatly improves the reliability of the magnetic suspension centrifugal compressor.