Adaptive Observer-Based Frequency-Locked Loops for Renewable Energy Systems: A Comparative Analysis

Fast and accurate grid synchronization is very important to integrate renewable energy systems to traditional electric power grid. In this context, frequency-locked loop (FLL) became very popular in recent time as a grid synchronization technique. Numerous FLL techniques are available in the literature. Out of them, adaptive observer-based FLL technique have attracted significant attention in the last few years. In this paper, we present comparative analysis of three recently proposed adaptive observer-based FLLs. By systematically tuning the FLLs, we present a benchmark study for adaptive observer-based FLLs. Through numerical simulation, it has been demonstrated that the performance of these techniques are very similar, however, they have their own merits and demerits. Results presented in this paper can be useful as a guideline for practitioners and academic community in the grid synchronization topic.