Synergizing pico hydel and battery energy storage with adaptive synchronverter control for frequency regulation of autonomous microgrids

Abstract

The proliferation of renewable energy sources in autonomous microgrids has led to the deterioration of system inertia. In the past decade, the decrease in system inertia was addressed through numerous virtual synchronous generator (VSG) topologies. Synchronverter is one such control technique exhibiting promising performance as that of synchronous machines (SMs). Recently, myriad other modifications were carried out to enhance the capability of the synchronverter for better dynamic response. However, the limitations of fixed virtual inertia and damping coefficient were left untouched, which can be optimized for better frequency regulation of microgrids. Hence, this paper proposes an adaptive synchronverter (ASV) by optimizing OSV parameters through fuzzy logic. Subsequently, the proposed ASV was employed to control a novel pico hydel and battery hybrid energy storage for frequency regulation of the microgrid. The small-signal model of parallel operating ASVs is presented along with the eigenvalue analysis to prove the system stability under parameter variation. The MATLAB/Simulink simulation results revealed that the proposed ASV exhibited a lower rate of change of frequency and frequency nadir compared to the original synchronverter (OSV) and vector control (VC).