Enhanced Inter-Battery Power Sharing in DC Nanogrids Using Adaptive Fuzzy Droop Control

This paper proposes an enhanced control strategy to improve both the accuracy and fairness of power sharing among Battery Energy Units (BEUs) in a DC Nanogrid (DCNG) system. In conventional configurations, variations in line resistance and differences in the State of Charge (SoC) often result in unequal power distribution, thereby reducing overall system efficiency and accelerating battery degradation. In order to address these challenges, the proposed method integrates adaptive droop control based on fuzzy logic with a novel virtual power rating concept. This approach enables precise and equitable power distribution by dynamically responding to system conditions, allowing BEUs with higher SoC to contribute more power while limiting the output of those with lower SoC to extend their service life. The control scheme is specifically designed to maintain a balanced 1:1:1 power-sharing ratio among three BEUs and to ensure DC bus voltage stability via an active voltage restoration mechanism that adapts to load changes. The strategy is validated through comprehensive MATLAB/Simulink simulations under varying load conditions and SoC profiles. Results demonstrate significant improvements over conventional control methods in terms of power-sharing accuracy, voltage regulation, and adaptability to changing operating scenarios. These findings highlight the potential of the proposed approach as an effective solution for optimizing energy management in distributed energy storage systems, particularly in DC nanogrid environments requiring high efficiency, operational reliability, and long-term sustainability.