Multifrequency Vibration Control for Active Magnetic Bearing Rotor System Based on Adaptive Cascaded Notch Filters

This article proposes a control strategy combining adaptive cascaded notch filters and distributed feedforward compensation, which is used to solve the problem of multifrequency vibration suppression and stable critical speed crossing in high-speed active magnetic bearing (AMB) rotor systems. High-speed rotating machinery often faces significant challenges from multifrequency vibrations, which can degrade system performance and stability. The four-degree-of-freedom rigid rotor dynamic model reveals the mechanism of multifrequency disturbance current generation caused by both rotor unbalance and sensor runout. This article introduces a cascaded notch filter topology reconstruction mechanism, which weakens the chattering caused by phase mismatch in the critical speed region by switching the input signal source of the tracking filter. Meanwhile, a dynamic compensation channel for displacement stiffness force is established, which can suppress multifrequency vibration forces without separating fundamental frequency disturbances. Through a cascaded multifrequency suppression structure, the cooperative filtering of 1st to 3rd harmonic disturbances is realized. Extensive simulation and experimental results demonstrate the efficacy of the proposed method: under both constant-speed and acceleration conditions, the strategy significantly reduces the 1st to 3rd harmonic disturbance components, with experimental reductions of up to 62.9%, 58.7%, and 14.4%, respectively at 65 Hz, and effectively improves system stability. This study provides a novel and effective vibration suppression solution for high-performance AMB systems.