Novel DC-AC Converter Topology for Multilevel Battery Energy Storage Systems

This paper presents a novel DC-AC converter circuit, especially for the application in multilevel battery energy storage systems (BESS), see fig. 1c. A drawback of the commonly used cascaded H-bridge is that the RMS values of the battery currents can reach multiples of the mean DC battery currents. Additional DC-DC converters in the cells can reduce the AC components of the battery currents, but cause additional semiconductor losses and require large inductors. The circuit presented in this paper reduces these AC contents with less semiconductor losses and smaller inductors than standard DC-DC converters connected to H-bridges.