Designing Online Controller using Differential Evolution Optimization Algorithm for Inverter-based Distributed Generation in Islanded Microgrid

In this paper, online controller scheme is proposed for voltage control of inverter-based distributed generations in islanded microgrid (MG). The MG has a completely nonlinear structure and its dynamics is constantly changing. As a result, linear controllers with constant and non-flexible coefficients are unable to provide a proper performance over a wide range of operating conditions. In response to this challenge, the present paper addresses an optimal online and nonlinear controller based on fuzzy logic. To improve the performance of the proposed controller, the differential evolution optimization algorithm is used to optimal tune its coefficient for the different MG operating scenarios. The goal of the proposed scheme is to control the voltage of the islanded MG at the standard level with the least transient state after the island's occurrence, as well as during load changes in island MG. In the proposed control scheme, proportional-resonant controller is used due to the advantages in order to voltage and current control of distributed generation units in the static frame space. The simulation results indicate the changing of the voltage controller coefficients, resulting in a better transient response, the elimination of the steady-state error and less harmonic distortion.