Inter-module SoC balancing control for CHB based BESS using multi-dimensional modulation

State of Charge (SoC) imbalance between battery modules is unavoidable in high capacity Battery Energy Storage Systems (BESS). This paper investigates a module level SoC balancing control in cascaded H-bridge inverter (CHB) based BESS using multi-dimensional modulation technique. Multi-dimensional modulation is a generalized modulation strategy for cascaded H-bridge inverters. With the proposed control strategy, SoC can be equalized between the battery modules in a phase leg of CHB. The performance of the proposed control strategy under faulty cell operation is also studied. The multi-dimensional modulation strategy and the SoC balancing control are explained and the simulation results are given in this paper.