An Isolated High-Voltage-Gain Resonant Converter Utilizing Voltage Quadrupler With Bi-Directional-Switch for Fuel-Cell Applications

This article proposes a high-voltage-gain resonant converter with zero input current ripple for fuel cell applications. The proposed converter comprises an interleaved current-fed bridge and a voltage quadrupler rectifier with a bidirectional switch on the primary and secondary sides of the transformer, respectively, for achieving high-voltage gain and zero input current ripple. Furthermore, it can achieve an additional increase in voltage gain by adjusting the duty cycle of the bidirectional switch, even with a fixed duty cycle of 0.5, which simultaneously ensures ripple-free input current. So, these structural advantages allow the converter to achieve a much higher voltage gain with the least transformer turns-ratio value than existing step-up converters. The voltage quadrupler also makes the output component's voltage stress half the output voltage. In addition, the resonant operation enables all the switches and diodes to fully attain soft switching over the operating voltage range. Thus, the reverse recovery problem of the diodes and the switching loss for all switches can be eliminated. Its operating principles and theoretical derivations of the converter are discussed in detail. The effectiveness and performance of the proposed converter were verified using a 400-W prototype operating under input voltage ranging from 38 to 48 V inputs and an output voltage of 380 V, achieving a peak efficiency of 96.4%.