A novel strategy to design enhanced performance robust controller for standalone VSI

A novel methodology for enhanced performance robust controller design is presented in this paper. The proposed method provides an efficient way to design a controller with an improved performance in terms of higher convergence rate of the system for the allowable uncertainties. The method is applied for the control design of standalone voltage source inverter. The control objective is to regulate its output voltage and frequency with an uncertain RL load. The dynamic equations of the system are used for uncertainty structure modelling. Then using Sylvester's criterion, new uncertainty conditions are developed. Assisting with these conditions and intelligent technique differential evolution (DE), the optimum robust controller is designed. For reference tracking, this robust control law is augmented with integral control, which is also designed using DE. Furthermore, to guarantee the robustness of the augmented control law, a numerical approach is proposed. The effectiveness of the methodology is illustrated by means of simulations and real time hardware in the loop experiments. A comparison of the proposed method with existing robust control design method is also presented to demonstrate the improvement in performance.