Robust and Reliable Voltage Regulation in Modern Power Systems Using Second-Order Sliding Mode Controller
Abstract
In the present study, a novel sliding mode controller (SMC) is proposed for robust and reliable voltage regulation in modern power systems. The proposed SMC is designed for a nonlinear model of an automatic voltage regulator (AVR) system having limiters in line with IEEE recommendations. The mathematical derivation of the control input is described in detail, and the asymptotic stability is guaranteed by Lyapunov stability theorem. The number of the controller parameters is reduced from four to two, and the control input is simplified without sacrificing the performance of the controller. This feature simplifies the control signal and makes the controller easy to optimize. It has been revealed that the number of controller parameters in the proposed study is less than the number ranging from three to seven in other AVR controller studies in the literature. The SMC algorithm differs from design-oriented studies in the literature in that it simplifies the control signal without affecting the controller’s performance. In the optimization stage of the study, the Sine Cosine Optimization Algorithm is conducted and its performance is evaluated with respect to a different number of agents and iterations. The results showed that the proposed controller parameters need very few simulations to find their optimum values. It can be easily seen that ten iterations with five agents are sufficient for the optimization of the proposed controller. It was clearly seen that the total number of simulations with 50 simulations in the proposed study was significantly less than the number of simulations in other related studies in the literature. The resulting optimum controller parameters were obtained as ksw = 744.5885 and k3 = 0.0711. A 0.5% overshoot at the output of the generator is allowed in the objective function of the optimization. Simulation results show that the proposed controller is robust and reliable against parameter uncertainties and various types of output disturbances.