Implementation of an interleaved resonant converter for high-voltage applications

An interleaved resonant converter for high voltage application is presented in this paper. There are two half-bridge legs connected in series and two split capacitors in the adopted circuit to limit the voltage stress of each active switch at one-half of input voltage. Thus MOSFETs with 600V voltage rating can be adopted for 1200V input voltage application. For each half-bridge leg, two series resonant circuits are operated with interleaved one-half of switching period. The secondary windings of two transformers are connected in series in order to balance the transformer primary currents and to share the input current. Thus the sizes of the transformer core and bobbin are reduced. The centre-tapped rectifier is used on the output side to reduce the conduction loss with one diode voltage drop. Based on the resonant behaviour, MOSFETs are turned on at ZVS, and rectifier diodes can be turned off at ZCS if the switching frequency is less than the series resonant frequency. Two half-bridge legs are operated with one-fourth of switching period such that the ripple currents at input and output sides arc reduced. Finally, experiments with a 960W prototype, verifying the effectiveness of the proposed converter, are described.