Reconfigurable battery energy storage system for utility-scale applications

The application and research interest over utility-scale battery energy storage systems have grown significantly over the last years. To achieve utility-scale, series and/or parallel connection of many battery packs with power rating of a few hundreds kilowatts each is the most viable technology at present. The major challenge regarding the connection of battery packs is charging imbalance. This paper proposes a solution using reconfigurable selection panels and series-connected dual-active-bridges to connect many battery packs directly to a medium voltage level bus. The proposed control algorithm facilitates optimal battery operation by prioritizing the packs to be used based on different operation conditions, so that rest time for each battery pack is guaranteed. It also optimizes the charging/discharging processes of the packs to extend the life of the batteries. Simulation results using MATLAB/Simulink and PLECS confirm the effectiveness of the proposed solution.