Droop Based Power Programmable Algorithm in DC Microgrids

This paper studies a droop based control algorithm for DC microgrids which aims at tracking the power and stabling the bus voltage. The proposed algorithm consists of three different timescale control levels, that is, the primary control applies the traditional droop control to achieve the power share, the secondary control compensates the voltage deviation caused by droop control and the tertiary control adopts the PI controller to track the reference power. The proposed strategy implements the programmability of DG output power, which is compatible with various upper layer power scheduling algorithms, but also the sharing of power fluctuation due to contingencies and/or load variations. Simulation studies on several cases demonstrate its effectiveness.