Adaptive Droop Control to Reduce Steady-State Power Imbalances in DC Microgrids

DC Microgrids (DCMGs) are gaining significant attention in the field of power electronics due to their superior reliability, efficiency, and adaptability in comparison to AC microgrids. Several types of control are employed in DCMGs, with droop control emerging as the predominant choice. However, the mismatch of line impedances leads to power-sharing errors that are not fixed by the conventional droop approach. This paper presents a novel adaptive droop control to address the steady-state power-sharing imbalance among grid-forming converters in DCMGs. The DCMG under examination comprises two battery banks that form the energy storage system (ESS) serving as grid-forming units, alongside distributed generation (DG) units, and loads. These systems are connected to a common bus through DC-DC converters. Based on the proposed technique, an operational procedure is delineated to acquire real-time data based on the existing line impedance mismatches. The proposed technique considers only the output power of the elements to adjust the droop coefficient, thus mitigating the steady-state power imbalances among the ESS units. A section conducting an in-depth analysis of the method under different droop gain adjustments is also presented. Simulation results are presented to showcase the system's operation under different operation scenarios. The findings indicate the feasibility and effectiveness of the proposed approach.