Control of Magnetic Bearings for Rotor Unbalance With Plug In Time Varying Resonators

Abstract

Rotor unbalance, common phenomenon of rotational systems, manifests itself as a periodic disturbance synchronized with the rotor's angular velocity. In active magnetic bearing (AMB) systems, feedback control is required to stabilize the openloop unstable electromagnetic levitation. Further, feedback action can be added to suppress the repeatable runout but maintain closedloop stability. In this paper, a plugin timevarying resonator is designed by inverting cascaded notch filters. This formulation allows flexibility in designing the internal model for appropriate disturbance rejection. The plugin structure ensures that stability can be maintained for varying rotor speeds. Experimental results of an AMB–rotor system are presented.