Small-signal Analysis of DC Microgrid and Multi-objective Optimization Segmented Droop Control Suitable for Economic Dispatch

To obtain a larger controllable range of output/input power of droop-control sources, a multi-objective optimization segmented droop control suitable for economic dispatch for a DC microgrid is proposed. According to the small-signal analysis, the worst point of the stability in the droop-control curve is determined through the analysis of a simplified model with multiple droop-control sources. By considering the worst points of stability as constraints, an elitist non-dominated sorting genetic algorithm is used to search the better turning points of the proposed droop-control curves after obtaining the new rated operation points from the system-layer economic dispatch. Simultaneously, optimization objectives, including the influence of eliminating the line resistance and capacity matching, are considered in the search process. Finally, the simulation results of the DC microgrid simulation model based on RT-Lab are presented to support the stability conclusion and proposed droop control.