Experimental Investigations of Resonance Vibration Control for Noncollocated AMB Flexible Rotor Systems

The resonance vibration control of active magnetic bearing (AMB) supported flexible rotors is a challenging topic in the industrial applications. This work addresses the two issues on the noncollocated AMB flexible rotor systems while passing through the critical speed. A modal separation scheme is established to enhance the observability of the bending mode, and a damping optimization procedure of the electromagnetic force is proposed to provide the maximum control efficiency. First, the rotor imbalance analysis is carried out, and several possible approaches to minimize the vibration of the flexible rotor are presented. Then, the detailed descriptions of the bending mode extraction scheme using notch filters and phase-lead compensators are discussed for a noncollocated flexible rotor system. The root locii of the closed-loop AMB-rotor system with and without additional phase-lead compensator are also performed. A solution to determining the phase angles between the measured rotor displacements to the bearing forces is established using the physical modeling and experimental identification. Finally, simulation and experimental results on a 10 kW magnetically suspended centrifugal compressor show the effectiveness of the proposed methods.