A robust LQR-FOPIλDµ controller design for output voltage regulation of stand-alone self-excited induction generator

Abstract

This paper presents several optimal controllers compared with a robust control method for the terminal voltage regulation of a stand-alone self-excited induction generator (SEIG) with fixed capacitor and thyristor controlled reactor (FC-TCR). The major challenge of designing process of the controllers is the nonexistence of perfect model of SEIG. Therefore, small-signal based models for the output voltage and frequency are carried out using real input-output data. Accordingly, Linear Quadratic Regulator (LQR), Linear Quadratic Integral (LQI) and Linear Quadratic Fractional Order Integral (LQFOIλ) controllers are designed to regulate output voltage. Moreover, novelty and main contribution of the paper is to design a hybrid controller which combines LQR and Fractional Order Proportional Integral Derivative (LQR-FOPIλDµ) controller to ensure the best tracking dynamics, robustness against disturbances and sensor noise suppression. The proposed hybrid LQR-FOPIλDµ controller is obtained by solving H∞ weighted mixed sensitivity problem. Optimization process of the controller parameters is implemented by using particle swarm optimization (PSO) algorithm. Matlab/Simulink program is used to compare the effectiveness of the proposed controllers. Furthermore, the experimental results show that robust LQR-FOPIλDµ controller has the best tracking dynamics among them with less overshoot, settling time as well as the robust structure against external disturbances and sensor noises.