Analysis and Evaluation of Unbalance Resonance Vibration and Bearing Reaction Force for Active Magnetic Bearing Equipped Flexible Rotor.

Active magnetic bearing (AMB) equipped rotating machinery requires control for low unbalance vibration at low driving power. In order to estimate both the unbalance resonance vibration and the bearing reaction force, an unbalance response analysis program considering the bearing reaction force is developed. Using this program, the optimum control technique is evaluated for flexible rotors supported by AMBs, regarding the following four means: PID, Ncross, Ncut+Ncross and Feed Forward (FF) Excitation. FF Excitation is recommended with respect to low resonance amplitude and low control current in order to pass the first bending critical speed.