Comparative Study of an Optimal Control Scheme in Different Magnetic Bearings' Geometries

Active Magnetic Bearings (AMB) are devices that support a shaft, showing the advantage of having no contact with any rotating parts, thus eliminating wear and the need of lubrication. Intrinsically, these equipments are unstable and, therefore, a control strategy is necessary in order to stabilize the system. One of the most used state-space feedback method is the Linear Quadratic Regulator (LQR). This paper aims to simulate and compare the eight, four and three-pole AMB with the centralized, decentralized and two-parameter decentralized LQR control strategies. After deducting the reluctance force equations and the system dynamics equations for each of the geometries, several simulations were performed. The results were conclusive and indicated the preference to use the two-parameter decentralized controller, due to the shorter stabilization time and the control variables decoupling, among other factors.