Voltage Control and Stabilization of Distributed and Centralized DC Micro Grids

This paper describes a distributed DC micro grid voltage control strategy. Starting point is the small-signal modelling of DC/DC converters interfacing sources and loads to a DC supply bus. Based on this model, a stability analysis of the micro grid can be conducted. Voltage control is realized with a droop control technique. This proposed method is optimized for a DC micro grid with several distributed sources. It is shown, that different droop characteristic curves can influence the grid behavior of the source converters to realize a safe and reliable energy management of distributed resources and a stable operation of the grid. Finally, a proof of concept is being done with a case study on a small experimental grid with two distributed source converters and two loads. The measurement results and the performance of this method are presented.