A New Interleaved Series Input Parallel Output Zero-Voltage-Switching Forward Converter

A new interleaved soft-switching forward converter is proposed in this paper. Two active-clamp forward converters are connected in series input and parallel output structure to share the input voltage and output current. The output capacitance of switches and the resonant inductance are utilized to realize the resonance at the transition interval of switches such that the zero-voltage-switching (ZVS) operation for all switches can be achieved. The current-doubler rectifier with ripple current cancellation is used to reduce the current stress of the transformer secondary winding. The interleaved PWM operation also diminishes the current ripple in the output capacitor to reduce the size of the output filter. All these features make the proposed converter suitable for high input voltage, high output current and high efficiency applications. The operating principles, steady-state analysis and design considerations of the proposed converter are presented. Finally, experimental results based on a 240 W (12V/ 20A) prototype are provided to verify the effectiveness of the proposed converter.