A High Step-Up Soft-Switched Converter Based on Coupled Inductor and Current-Fed Voltage Multiplier

In this paper, a novel non-isolated DC-DC converter that combines coupled inductor (CI) and voltage multiplier (VM) techniques is proposed. The leakage energy of the CI is effectively recycled, and soft-switching conditions are achieved for all switches and diodes. Resonance between the leakage inductor of the CI and VM capacitors provides soft-switching conditions, without requiring a separate resonant tank. The use of VM stages not only lowers the voltage stress on semiconductor components but also allows for the use of low-voltage-rated devices, leading to reduced conduction losses, lower cost, and improved efficiency. High voltage gain can be achieved by appropriately adjusting the switching duty cycle, the CI turn ratio, and the number of VM stages—offering three design degrees of freedom. The operation principles, steady-state analysis, component stresses, design guidelines and performance comparison are presented in detail. Finally, a 500 W prototype converter with an input voltage range of 40–50 V and an output voltage of 1 kV at 200 kHz switching frequency is implemented and tested under worst-case conditions to validate the proposed converter.