A new ultra-high gain CI-based DC/DC converter with low voltage and current stresses.
By integrating a three-winding coupled inductor (TWCI) with voltage multiplier cells, this study proposes a quadratic DC-DC converter that achieves ultra-high voltage gain while maintaining continuous input current and a common ground. The proposed coupled-inductor topology is specifically engineered to minimize both voltage and current stresses across all circuit components, thereby enhancing overall performance and enabling potential cost reductions. Enhanced design flexibility is a key feature of the proposed configuration, particularly because the secondary winding of the TWCI operates in a semi-trans-inverse manner, allowing high voltage gains to be realized even with a very low turns ratio. Regenerative passive clamp circuits are incorporated to recover the leakage energy of the TWCI and to limit voltage stresses on the active switches, which are driven with simultaneous switching patterns. The converter's vertical structure further alleviates semiconductor voltage stress, while intrinsic current sharing between the TWCI and the input inductor substantially reduces power dissipation in the main power components. Additionally, turn-off switching losses of both active switches are minimized via a quasi-resonant cell. The paper presents a comprehensive steady-state analysis, detailed power loss evaluation, a comparative study with existing topologies, and key design guidelines. All theoretical contributions are conclusively validated through experimental results obtained from a 200 W hardware prototype, converting a 25 V input to a 400 V output.