Negative Imaginary Theory-Based Proportional Resonant Controller for Voltage Control of Three-Phase Islanded Microgrid

This paper demonstrates the design of robust proportional resonant (PR) controller using negative imaginary (NI) theorem for voltage control of three-phase islanded microgrid (MG) application. While operating MG as the islanded mode, different types of random and unknown load dynamics affect the MG. These loads eventually deteriorate the proper execution of MG-inducing disturbances in voltage and current. Therefore, to improve the performance of the three-phase MG, a simple, second-order controller is designed with the combination of NI theory and PR (NI–PR) controller. This controller is capable of providing higher level of damping as well as excellent stability properties. The stability and effectiveness of this controller are examined through imposing uncertainties, in terms of several load dynamics as well as different fault conditions. The comparison with respect to linear quadratic regulator and model predictive controller also ascertains the robustness of the designed controller. The NI–PR controller and the system are simulated in MATLAB/SIMULINK platform.