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MULTIRATE STABILIZATION TECHNIQUES APPLIED TO A HYDROGENERATOR-UNIT FOR THE DESIGN OF EXCITATION CONTROLLERS
*Dr. Boglou A. K., Casini E. and Pappas D. I.
An optimal control strategy is used to design, in this paper, a desirable excitation controller of a hydrogenerator system, in order to enhance its dynamic stability characteristics. The proposed control strategy based on Two-Point-Multirate Controllers (TPMRCs) is readily applicable in cases where the state variables of the controlled plant are not available for feedback. In the TPMRCs based scheme, the control is constrained to a certain piecewise constant signal, while each of the controlled plant outputs is detected many times over a fundamental sampling period T0. On the basis on this strategy, the original problem is reduced to an associate discrete-time linear quadratic (LQ) regulation problem for the performance index with cross product terms, for which a fictitious static state feedback controller is needed to be computed. Simulation results for the actual 117 MVA hydrogenerator unit, show the effectiveness of the proposed method which has a quite satisfactory performance.[Full Text Article]