Identification of Flexible Rotor Suspended by Magnetic Bearings

Magnetic bearings are widely applied in High Temperature Gas-cooled Reactor (HTGR), where the rotating machineries are running under high purely helium environment. In designing and adjusting a magnetic bearing system, the mathematical model of the rotor plays an important role. Identification is a useful method to obtain the model of a rotor. However, there are some practical difficulties of identifying a magnetic bearing-rotor system without force sensors. This paper proposes an identification method for flexible rotor suspended by magnetic bearings. In this method, two experiments under different bearing stiffness are performed, the models obtained by these two experiments are then transformed to the desired rotor model and the influence of bearing stiffness is eliminated in this transformation. The proposed method is validated on an experimental system with a five degree-of-freedom suspended flexible rotor.