Unidirectional Isolated Resonant Switched Capacitor Converter With CDD Auxiliary Circuit

To cope with the requirement of DC-DC converters in the high voltage applications, a unidirectional isolated resonant switched capacitor converter (UI-RSCC) is proposed in this paper. Furthermore, the CDD auxiliary circuit is employed to suppress the voltage oscillation and eliminate duty ratio loss. Voltage self-balancing is achieved of the DC capacitors, which simplify the control. The required switching devices are reduced by multiplexing parts of switching devices. First, the UI-RSCC topology is introduced. Based on the analysis of parasitic capacitance and duty ratio loss, CDD auxiliary circuit is introduced to UI-RSCC to suppress the voltage oscillation, the operation principle and soft switching conditions are discussed. Finally, the rationality and effectiveness of the topology and control method are verified through simulation and experiments. The results showed that compared to U-IRSCC, the average efficiency increases by 0.39% with the adoption of CDD auxiliary circuit.