A High Step-Up Resonant Converter Based on Current-Fed Voltage Multiplier Technique

An extendable nonisolated resonant dc-dc converter based on current-fed voltage multiplier (VM) technique is proposed in this article for high step-up applications. These VM cells capacitors participate in a resonant network; therefore, no additional elements are required to provide a resonant tank circuit to realize soft switching conditions for power switches. Zero voltage switching and zero current switching conditions are realized here for switches and diodes, respectively. Consequently, mosfets dominant switching losses and the diodes reverse recovery problems are well overcome. Furthermore, the input source current waveform is continuous. Also, using the VM cells reduces the power devices voltage stresses. Accordingly, low voltage rating devices can be used, which reduce conduction losses and cost, and improve the converter efficiency. Also, by using more VM cells, the proposed converter can be used for high-voltage applications, without using extremely high duty cycle values to regulate the output voltage. The operation principles, steady-state analysis, design guidelines, and main characteristics of the proposed converter are given here, in detail. Finally, an 800 W prototype converter, with 80-100 V input voltage and 2 kV output voltage, has been implemented to validate the given analyses, simulation results, as well as to show the proposed converter main advantages.