Designing the Robust Fuzzy PI and Fuzzy Type-2 PI Controllers by Metaheuristic Optimizing Algorithms for AVR System

Abstract

In this paper, two robust controllers have been designed to automatically regulate the synchronous generator voltage for an extensive domain of the system parameters in a single-machine infinite bus (SMIB) framework. These two controllers are based on the fuzzy set, and the type-2 fuzzy logic plus the proportional–integral (PI) operation, respectively. The Fuzzy and Type-2 fuzzy logic decisions are independent of the system parameters which increase the system robustness against the uncertainties and disturbances, and the PI controller can eliminate the terminal voltage steady-state error. The performance of the controllers has been optimized by adjustment of the four coefficients of each controller through Artificial Bee Colony, Imperialistic Competitive Algorithm, and Particle Swarm Optimization (PSO). Five scenarios with four different patterns for reference input and disturbances have been considered to show the competency of the designed controllers. The simulations which have been done by PSO optimization results show the higher robustness of these controlling combination against the load fluctuations, the sequence of the input voltage, and changes in the system parameters, such as the gains and time constants of the amplifier, exciter, and generator in contrast to optimized PID with metaheuristic algorithms.