DESIGN AND ANALYSIS OF INTERNAL MODEL CONTROLLER AND ITS VARIANTS

Abstract

Internal model control (IMC) methodology is an controller design procedure that has acquired wide popularity due to its simple structure and ease of tuning. The work undertaken in this thesis primarily deals with the formulation and proposition of fractional order based control strategies based on the principle of internal model control. The fundamentals of the internal model scheme are revisited and recapitulated briefly. Subsequently, the one degree of freedom fractional order internal model control technique (1-DOF-FO-IMC) is integrated with the concept of model order reduction via Pade approximation for model simplification, and applied for the load frequency control of single area power system with hydro turbine, which is a challenging problem in the realm of power systems control. To further ameliorate the control performance of 1-DOF-FO IMC approach, an additional controller is incorporated in the feedback path of the system for the rejection of disturbance, leading to the proposition of a novel and an innovative two degree of freedom fractional order internal model control procedure (2-DOF-FO-IMC) for nominal and time delayed systems. An enhancement in the system performance tuned via the 2-DOF-FO-IMC technique is observed over the 1-DOF-FO-IMC scheme. Apart from the illustrative examples, the proposed 2-DOF-FO-IMC scheme is also applied for the”load frequency control of power system.” An extensive comparative and robustness analysis is a testimony to the efficacy of the proposed technique.