Imbalance compensation and automation balancing in magnetic bearing systems using the Q-parameterization theory

The problem caused by imbalance in rotating machinery can be solved using actively controlled magnetic bearing systems. There are two methods to solve this problem using feedback control: 1) compensate for the imbalance forces by generating opposing forces on the bearing surface; and 2) make the rotor rotate around its axis of inertia so no imbalance forces will be generated. The dynamics of the magnetic bearing are described in state-space form using airgap displacement, velocity, and airgap flux as state variables. The system which is unstable in nature is stabilized using the Q-parameterization theory. To compensate for the imbalance disturbance forces, the controller Q-parameter is chosen such that rejection of sinusoidal disturbances is achieved. To achieve automatic balancing, the imbalance is assumed as a sinusoidal noise in the measured signal, and the controller Q-parameter is chosen such that rejection of sinusoidal noise is achieved. Simulation results are presented and show the robustness of the proposed controllers and that the rejection of sinusoidal disturbances is achieved. The rotation of the rotor around its axis of inertia is also achieved