A Symmetrical Control Scheme for a Resonant Switched-Capacitor Converter with Inverted Output Voltage

Resonant switched-capacitor converter (RSCC) is an attractive topology for high power density applications. In this paper, a symmetrical control method is proposed to minimize the inductor RMS current for the RSCC and maintain soft switching for all active switches, which combines phase-shift and frequency modulation control. It reduces the switching frequency under high output power load conditions in comparison to the conventional phase-shift control. Meanwhile, all MOSFETs are turned on with zero-voltage-switching (ZVS) and two of them are turned off with minimal current. As a result, both switching loss and conduction loss can be reduced and it achieves high efficiency and high power density. The experimental results from a 400W prototype show good performance of the proposed control method, and a peak efficiency up to 99.32% is achieved at nominal input and output condition.