Automatic loop shaping of QFT robust controller for load frequency control via nonlinear quadratic inequalities

Abstract

The large scale power systems are liable to performance deterioration due to the presence of sudden small load perturbations and parameter uncertainties. Due to this, modern control aspects are very important in Load Frequency Control (LFC). This paper presents a robust load frequency controller design based on Quantitative Feedback Theory (QFT). QFT is an engineering control design methodology that explicitly emphasizes the use of feedback to simultaneously and quantitatively reduce the effect of plant uncertainty and satisfy performance specifications. This new controller method not only handles the parametric uncertainty in power system, but also covers a wide range of load changes. This paper also presents automatic loop shaping phase in the QFT design, inorder to synthesize an optimal controller.