Vibration Suppression of Active Magnetic Bearing System with Precise Frequency Estimation Method

In the active magnetic bearing systems (AMB), synchronous vibration of rotor is an inherent phenomenon due to the inevitable mass unbalance problem. This paper proposes an active vibration control method with precise frequency estimation for synchronous vibration suppression. Firstly, a universal control model with mass eccentricity is established and analyzed. Then, a frequency estimation strategy based on phase-locked loop (PLL) method is proposed to detect the frequency information precisely without any hardware costs. Besides, the stability of the whole system is strictly proved through the eigenvalues analysis of the characteristic equation. Furthermore, a zero-displacement vibration control method is proposed based on coordinate transformation method (CTM), which achieves high-precision detection of the synchronous component of radial displacement. And the related simulation results show that the synchronous vibration of rotor can be eliminated completely and rapidly with the proposed strategy, which agrees with the theoretical analysis.