A resonant switched-capacitor converter for voltage balancing of series-connected capacitors

This paper describes a resonant switched-capacitor converter (RSCC) for voltage balancing of several capacitor or battery modules connected in series. This voltage balancing circuit transfers electric charge between the capacitor modules with a soft switching operation, resulting in a reduction of power loss and EMI. Moreover, a phase-shift control method enables to improve its voltage-regulation performance. Its current loops are analyzed in a circuit configuration which has more than three capacitor modules. Based on the analysis, a new controller is designed to improve the transient response. Experimental results confirm the validity and effectiveness of the proposed control method.