State-of-charge balancing control of battery energy storage system based on cascaded H-bridge multilevel inverter

Cascaded H-bridge is a promising topology for high-voltage high-power applications. And in this paper, a cascaded H-bridge multilevel inverter for BESS applications is introduced. In order to manage the state-of-charge (SOC) value of each battery to be equal to avoid the over charge or over discharge, phase-phase SOC-balancing control and inter-phase SOC-balancing control are analyzed in this paper. 2MW/10kV high-voltage BESS based on cascaded H-bridge inverter has been completed and put into operation. Experimental results show the validity of proposed control method.