Optimal LCL-filter Design for a Single-Phase Grid-Connected Inverter Using Metaheuristic Algorithms

The inductor-capacitor-inductor (LCL) filter is used to lower the high-frequency switching noise of a grid-connected inverter (GCI). However, a robust design of the LCL filter is a challenge due to its complex model, variations in the operating conditions of the grid, and its stability gain margin. Therefore, this paper designs an optimal LCL filter for GCI and considers the changing grid conditions. This paper utilized four metaheuristic optimization algorithms, including the Whale Optimization Algorithm, the Circle Search Algorithm, the Particle Swarm Optimization, and the gray Wolf Optimization. These algorithms are applied to minimize the total harmonic distortion (THD) and the error between the reference and real grid current. The robustness of the optimal LCL filter is investigated under transient and steady states of the grid by using MATLAB/SIMULINK and real-time simulations. The obtained results revealed that the optimal LCL filter is capable of reducing the THD under different grid variations.