This chapter presents linear quadratic regulator (LQR) for tuning the parameters of four-term proportional-integral-derivative plus second order derivative controller for controlling terminal voltage of alternator equipped with automatic voltage regulator (AVR) system. Different optimization techniques are considered for juxtaposition with the proposed controller on the basis of terminal voltage response profiles of the AVR system, and Bode plot analysis is carried out for comparing the frequency responses, and through root locus, the stability of the proposed controller is investigated. On-line responses are obtained by implementing a fast performing Sugeno fuzzy logic technique in the controller for working in off-nominal and on-line situations. The controller has undergone an investigation, while having changed system parameters, for the analysis of the robustness of the proposed controller. It is revealed that the performance of the proposed LQR-based controller exhibits a highly improved robust control system for controlling the AVR in power systems.
