System efficiency estimation of redundant cascaded-cell converters in applications with high-power battery energy storage systems

Battery energy storage systems (BESS) become increasingly more important due to the impact of volatile energy sources on the power supply and present a good solution for buffering the power imbalances in the electric grid. Particularly with regard to a future scenario with electrical energy, means have to be taken to ensure a stable and reliable power supply. Redundant BESS allow normal operation, even if parts of the storage system are out of service. The nine-level cascaded cell converter is a promising topology for connecting batteries to the medium-voltage grid. In this paper, the extension of this topology to a redundant system is discussed.