A Resonant Switched-Capacitor Converter for Voltage Balancing of Several Capacitors Connected in Series

Abstract

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 carries an electric charge between the capacitor modules with a soft switching operation, resulting in a reduction in power loss and EMI. Moreover, a phase-shift control method is applied to improve the voltage-regulation performance of the RSCC by applying a voltage feedback control. This paper analyzes the relation between the capacitor currents and the resonant currents in the RSCC. Based on the analysis, a new controller is proposed for a circuit configuration having capacitors more than three. The experimental results confirm the validity and effectiveness of the proposed control method.