Distributed Adaptive Droop Control Method for Flexibility Enhancement of Islanded DC Microgrids Including Electric Springs

DC Microgrids (DC-MGs) are gaining attention as they pave the way for merging various means of energy resources with DC outputs. In the context of islanded DC-MGs, the intermittent nature of renewable energy resources and the uncertainty in demand profiles across various timescales pose prominent challenges for ensuring continuous power supply. To overcome this concern, a combination of generation units and energy storage systems are conventionally employed. However, in this paper, the storage system is replaced by the electric spring, which is a more effective demand-side management technique, aimed at enhancing flexibility in response to potential uncertainties and regulating the common bus voltage of standalone DC-MGs. To provide proper energy-sharing coordination between different resources, a distributed adaptive droop control strategy is employed. An adaptive droop method seems inevitable because voltage regulation or current-sharing accuracy can be significantly affected by line impedances, especially under high-load states. The effectiveness of the presented method has been verified through simulation scenarios using MATLAB®/Simulink.