A New Control Method of a Resonant Switched-Capacitor Converter and its Application to Balancing of the Split DC Voltages in a Multilevel Inverter

This paper proposes a new voltage-balancing circuit for the split dc voltages in a diode-clamped five-level inverter. The proposed circuit is based on a resonant switched-capacitor converter (RSCC), which consists of two half-bridge inverters, a resonant inductor and a resonant capacitor. A new phase-shift control of the RSCC is proposed to improve voltage balancing performance. As a result, it is possible to reduce the inductor to one tenth in volume as compared to a conventional voltage-balancing circuit based on a buck-boost converter. Experimental results are shown to verify the viability of the RSCC-based voltage balancing circuit.