IMBALANCE COMPENSATION AND AUTOMATION BALANCING IN MAGNETIC BEARING SYSTEMS USING THE Q-PARAMETERIZATION THEORY

This paper utilizes the e-parameterization theory to design a controll er which solves the problem of imbalance in magnetic bearing systems, The e-parameterization theory characterizes the set of all stabilizing controllers of a given plant in terms of a free parameter Q which is chosen such that design goals are achieved, Due to imbalance in the ro tor of rotating machinery, sinusoidal disturbance forces are generated which cause undesirable vibrations, The problem caused by imbalance i n rotating machinery can be solved using actively controlled magnetic bearing systems, There are two methods to solve this problem using fee dback control, The first method is to compensate for the imbalance for ces by generating opposing forces on the bearing surface. The second m ethod is to make the rotor rotate around its axis of inertia (automati c balancing); in this case no imbalance forces will be generated, Firs t, the dynamics of the magnetic bearing are described in state-space f orm using airgap displacement, velocity, and airgap Aux as state varia bles, Second, the system which is unstable in nature is stabilized usi ng the e-parameterization theory, To compensate for the imbalance dist urbance forces, the controller e-parameter is chosen such that rejecti on of sinusoidal disturbances is achieved, To achieve automatic balanc ing, the imbalance is assumed as a sinusoidal noise in the measured si gnal, and the controller e-parameter is chosen such that rejection of sinusoidal noise is achieved, In both cases the frequency of the sinus oidal disturbance/noise is assumed to be equal to the rotational speed , Simulation results are presented and show the robustness of the prop osed controllers and that the rejection of sinusoidal disturbances is achieved, The rotation of the rotor around its axis of inertia is also achieved.