The AC battery - A novel approach for integrating batteries into AC systems

This paper presents the so-called AC Battery - a novel modular multilevel parallel converter based split battery system for AC applications, enabling dynamic switching of battery cells in parallel and in series. Each individual battery cell may be interconnected to its neighbors according to operational needs, e.g. to provide optimum source resistance, lowest state-of-charge (SOC) cycling, and balanced aging, rendering separate battery management systems (BMS) unnecessary. Applying the proposed technology in grid scale BSS may fundamentally change existing system architectures, as it merges battery storage system and power converter. This forms the basis for a highly integrated power electronics unit that includes bidirectional grid connection capability, energy storage, and BMS.