Distributed Cooperative Control of DC Microgrids, Current Regulation and Voltage Tracking

A hierarchical control strategy is designed to control the current and voltage deviations of power nodes in a ring-based DC Isolated Micro-Grid (DCIMG), where each power node consists of Distributed Energy Resources (DERs). In the primary control level, a droop-based control scheme is employed to locally control the voltage deviations over DERs. In the secondary control level, a graph-based distributed cooperative control strategy is employed to globally control the current and voltage deviations over the power nodes. Where, in the case of current control, the nodes are regulated, and in the case of voltage control and optimisation, all the nodes are regulated as well as synced to a pinned node (leader) owning the minimum oscillation and deviation from the desired voltage of DCIMG. Accordingly, the leader and the followers are dynamically homogeneous as it facilitates to achieve the global voltage synchronisation of DCIMG. Simulation results of the proposed secondary current and voltage control are presented and discussed.