Diode-clamped multilevel converter topology for battery cells charging applications

A new charger control strategy for optimum charging of individual battery cells is proposed. The charger can directly charge individual battery cells based on their state-of-charge (SOC) using multilevel converter topology. In multilevel converter, individual cells are connected in series on the DC side of the converter. By choosing switching pattern and their duration in a combined manner, the charging current in each cell of the converter can be controlled very competently. The technique using diode-clamped multilevel converter is an excellent candidate for the unification of the charger and the individual cell current controller. The proposed control technique in balancing the individual cell charging currents is verified for different operating conditions.