Cooperative Control Strategy of DC Microgrid Clusters Based on Adaptive Droop Control

In DC microgrid clusters, the access of multiple microgrids with large differences and fluctuations will affect the stable operation of the microgrid clusters. To solve this problem, first of all, an adaptive sagging control strategy is proposed. Energy storage can be controlled according to its own state of charge(SOC) and capacity are used for power distribution, which effectively avoids overcharge and overdischarge of energy storage battery. Meanwhile, line impedance and voltage drop compensation are added to eliminate power balance deviation caused by line impedance and voltage deviation caused by droop control. Secondly, the cooperative control strategy of three operating modes, namely, autonomy of microgrid, mutual aid between clusters and collaboration of clusters and grid, is constructed, in which the cooperative coefficient is introduced, and combined with the improved droop control, the voltage exceeds the limit can be connected to the grid, so as to ensure the stable operation of microgrid clusters. Finally, three typical scenarios are used to verify the effectiveness of the proposed cooperative control strategy.