A two-level SOC balance strategy for a novel hybrid energy storage topology

A novel supercapacitor-battery hybrid energy storage topology is proposed. It has all the advantages of modular multilevel converters but its cost is relatively lower. The paper also proposed a two-level SOC balance strategy to realize SOC balance of batteries and supercapacitors in the whole system. The method composed of the balance strategy for branches and the strategy for SOC balance between phases. And experimental results verified the advantages of the topology and the effect of the proposed equalization method.