Development of a control strategy for interconnection of islanded direct current microgrids

This study presents a control strategy for interconnection of a cluster of direct current (DC) microgrids operating at different grid voltages in islanded mode. In this study, two neighbouring DC microgrids (DCMGs) are interconnected through a bidirectional DC-DC converter (BDC) and DC cable. The BDC has been placed near to the low-voltage DCMG. The DCMGs consist of wind turbines, solar-photovoltaic systems, solid oxide fuel cell, micro-turbine generators, battery energy storage systems and varying DC and three-phase as well as single-phase alternating current loads. The proposed control strategy of the BDC is aimed at managing the bidirectional flow of power between the DCMGs to balance the power under various operating scenarios and fault conditions, while maintaining constant DC voltages of both the DCMGs. Simulations are carried out to verify the robustness of the proposed control strategy under different operating conditions including fault scenario.