A new step-up quadratic DC/DC converter based on coupled-inductor

This article introduces a novel ultra-high voltage gain DC-DC converter with a low component count, designed for renewable energy applications. In the presented topology, a three-winding coupled-inductor (TWCI) and a switched-capacitor network are embedded within a classic quadratic boost converter. This arrangement yields high voltage gain, ensures continuous low-ripple input current, and preserves a common ground between the source and the load. Due to its trans-inverse feature, the circuit achieves ultra-high voltage gain even with a very low turns ratio in the TWCI. The topology also features current sharing between the TWCI and the main power switch, which significantly reduces power losses in the main power switch and coupled-inductor device. To limit voltage stresses on the active switches, the circuit integrates two passive regenerative clamp circuits, with the switches themselves operated using simultaneous switching patterns. The paper provides detailed steady-state analysis, power loss calculations, comparative evaluation, and design considerations. Finally, a laboratory prototype rated at 200 W has been implemented to verify the theoretical analysis, achieving a very high voltage conversion from 20 V input to 400 V output.