Selection of Voltage Levels in DC Microgrids using DC Bus Signaling

DC Bus Signaling (DBS) is reported in the literature as an economical method for power management in DC microgrids, in which, the DC bus voltage is used as an indirect communication signal among the elements present in the microgrid. The bus voltage is regulated at different levels by different microgrid elements depending on the mode of operation. Choice of these voltage levels is guided by the microgrid architecture, type and length of cables, number of elements in the microgrid and acceptable voltage drop. This paper analyzes the factors responsible and the related trade-offs for selection of these voltage levels. Also, the extendibility of DC microgrid with the increase in distances among the elements and increase in number of elements is one major concern in DBS scheme. The DBS scheme discussed in this paper ensures effective power handling irrespective of the power/energy rating and availability of microgrid elements. Detailed simulation results are presented in support of the analysis.