A Design Method of an Optimal Parameter Controller for Active Magnetic Bearings-Flexible Rotor Systems

Flexible rotor systems supported by active magnetic bearings (AMBs) have sophisticated vibration characteristics due to the unbalance disturbance and flexible modes. In order to suppress the unbalance vibration of the AMBs-flexible rotor system in the full rotational speed region, an optimal parameter controller is designed. Firstly, the dynamic model of the AMBs-flexible rotor system was built. Then, the optimal parameter controller composed of a PID controller and a PD compensator with a notch filter was proposed. The PD compensator was used to tune the stiffness and damping under different rotational speeds, and the notch filter was used to avoid excessive synchronous control current. The numerical relationships among the compensator parameters, rotor displacements and control currents were built and analyzed. Moreover, a compensator parameter optimization problem was constructed and solved, whose objective function considers the rotor displacements at all nodes, control currents and parameter smoothness under different speeds. Simulation and experimental results confirm that the unbalance vibration and control current peaks can be effectively suppressed by applying the proposed controller compared with the normal PID controller.