Active DC bus signaling control method for coordinating multiple energy storage devices in DC microgrid

Management of multiple energy storage devices in a DC microgrid is a challenge. Conventional method, such as droop control, cannot ensure accurate current sharing in coordinating multiple battery banks, which limits the DC microgrid system performance. This paper proposed an active DC bus signaling (ADBS) method to coordinate multiple battery banks in a DC microgrid. It has the advantages of accurate current sharing. Using the proposed ADBS method, the master controller can collect State of charge (SoC) of each slave battery bank by actively varying the DC bus voltage levels and monitoring the current change. The master module then sets a working voltage level after decision-making. The proposed method was experimentally evaluated, and the experimental results show that all the possible working voltage levels can be reached and the accuracy of current sharing is guaranteed.