Rotor Modal Suppression in Active Magnetic Bearing System Based on Frequency-Locked-Loop Filter

Modal vibration of rotor seriously affects stability of magnetic bearing system. Once the rotor mode is excited, the vibration intensifies, which is easy to lead to the saturation of the power amplifier and further instability of the rotor system. The paper investigates a rotor modal suppression method based on frequency-locked-loop filter. The dynamic model of single-degree-of-freedom rotor is established. A frequency-locked-loop filter is added to the closed loop control system to estimate the modal frequency and suppress modal vibration. The proposed frequency locked loop can estimate all components of biased sinusoidal signals. Simulation results verify the effectiveness of the proposed method for rotor modal suppression.