Dynamic Modeling of the Active Magnetic Bearing System Operating in Base Motion Condition

Active magnetic bearing (AMB) has been increasingly applied in high-speed rotating machinery applications because of the inherent merit of providing contactless magnetic force to levitate rotor. Generally, rotor AMB systems are applied in the static base situation whereas the recent work has also demonstrated their applicability in moving base conditions. Compared with traditional static base condition, the base motion condition is more complicated for rotor AMB system. For a better controller design and dynamic analysis, the dynamic modeling of AMB system operating in base motion condition is critical. However, the dynamics modeling of AMB system working in base motion condition has been rarely reported. Particularly, the rotational base motions are always neglected. Herein, in this work, based on a double-gimbal system model, we propose and develop a dynamic modeling method for AMB system considering both translational and rotational base motions. The derivation reveals that the translational base motion is equivalent to the external force applied to the rotor and the rotational base motion is equivalent to the external torque applied to the rotor. Furthermore, making use of the proposed dynamic model, we also analyze the dynamics of rotor displacement in the impact base motion condition from the aspects of excitation amplitude, pulse width and supporting parameters.