Interleaved resonant converter with flying capacitor

This paper presents a new DC/DC converter for high input voltage and high load current applications. In order to adopt low voltage rating power devices in high voltage applications, two split capacitors with four active switches are used in the primary side to reduce the voltage stress of power switches at V_in/2. Two flying capacitances are used in order to automatically balance two split capacitor voltages in every switching cycle. The proposed converter includes two resonant circuits to share the load current and to reduce the current stress of passive components. If the switching frequency is less than the series resonant frequency, power switches can be turned on under zero voltage switching and rectifier diodes can be turned off under zero current switching. Therefore, the switching losses on power semiconductors are reduced. The interleaved pulse-width modulation is adopted to further reduce the ripple current at output side. Thus, the output filter inductances can be reduced. Finally, experiments with a 1.2kW prototype are provided to verify the effectiveness of the proposed converter.