Simulation of magnetic bearings rotor s critical characteristics by active variable supports
                                                  LANG Cheng ye, HU Xiong xin, XU Fang
(Key Laboratory of E&M., Ministry of Education & Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, China)

Abstract: Aiming at the excessive amplitude vibration and instability when rotor pass through the critical speed, and the method of the rotor system smoothly pass through the first critical speed were researched. Anew method of active variable support magnetic bearings rotor system for passing through the first critical speed was described in this paper. Firstly, the mathematical model of variable support magnetic bearings rotor system were established, and the response characteristics of the rotor supported by two and three magnetic bearings were analysed. Then, the simulation model was established by ADAMS, and the model co simulation was accomplished by using ADAMS and Matlab. The results indicate that when pass through the first critical speed the damping effect of variable support magnetic suspension rotor system is obvious, and the response amplitude can be reduced by 52.3% comparing with the traditional two bearing rotor system.

Key words: variable support; magnetic bearings; active control; critical speed