This paper proposes a strategy for state-of-charge equalization of batteries in stationary energy storage systems implemented in a three-phase cascaded multilevel converter. The approach consists of using level-shifted pulse width modulation technique with rotating triangular carriers, assisted by a sorting algorithm. The proposed control technique was verified through simulations in PSCAD/EMTDC software. The results highlight the strategy's potential for battery energy storage systems applications, especially in scenarios involving the integration of renewable energy sources.