Modelagem e controle ótimo de um mancal magnético de três polos

Abstract

Active Magnetic Bearings promote shaft’s support through magnetic levitation. They are unstable systems and require active control with electromagnets, sensors, power amplifiers, and closed-loop control to become stable. In the literature, the first proposed magnetic bearing geometry was that of eight poles, with independent magnetic fluxes. However, further research has suggested other configurations, such as 4-pole and 3-pole. This work shows the procedure of obtaining the reluctance forces for the magnetic bearings of 8, 4 and 3 poles. These forces have very complex nonlinearities, but since the region of study is close to the point of operation, linearization appears as a valid alternative for the analysis. For the 3-pole bearing, a mechanical dynamics model in state space is proposed, and the first suggestion to stabilize the system is optimum state feedback, with a Quadratic Linear Regulator, a centralized control. The second Control strategy suggested, called decentralized control, is a modification of the first, in an attempt to add more zeros to the feedback gain matrix, but still attending the same performance index.