Design and Control of Battery Energy Storage System Based on Cascaded Multilevel Converter with Reduced Low-Frequency Battery Current Ripple

A novel battery energy storage system (BESS) topology is proposed in this paper which is based on the combination of cascade multilevel converter (CMC) and power switch multiplexing technique. The low-frequency ripple in battery current which is pulsating at twice the output frequency can be significantly reduced. While only four power switches are required in each submodule, and no extra power decoupling circuits are needed. This topology possesses the advantages of lower number of power switches, simpler circuit structure, and higher reliability. The circuit configuration and operation principle are analyzed. The individual phase current control (IPCC) is also presented which can make BESS adapted to unbalanced conditions automatically. Finally, simulation results performed in PSCAD/EMTDC can verify the circuit performance and control strategy.