A New Trans-Inverse Coupled-Inductor High Step-Up DC/DC Converter with Low Voltage Tensions

This paper presents a new single-switch DC-DC converter with ultra-high voltage gain, low input current ripple, and low voltage stresses. This circuit combines a three-winding coupled inductor (TWCI) with a vertical Cockcroft–Walton Voltage Multiplier (CW-VM) to achieve ultra-high voltage gain without requiring a large duty cycle. Unlike typical coupled-inductor-based converters, the proposed topology employs a trans-inverse configuration that enables higher voltage gains through reduction of the TWCI's secondary turns ratio toward zero. Furthermore, the adjustable turns ratios of the TWCI enhance design flexibility, enabling greater voltage gain optimization compared to conventional topologies. Additionally, a regenerative clamp capacitor effectively constrains the maximum voltage stress across the power switch. The TWCI's leakage inductances enable soft-switching performance for the power switch and also mitigate diode reverse-recovery losses, collectively improving conversion efficiency. Moreover, the TWCI's leakage inductance is actively employed to form a resonant cell, significantly reducing switching losses. The paper presents a comprehensive analysis of operation principles, steady-state performance, and comparative evaluation with similar counterparts. Theoretical findings are experimentally verified using a 250W, 25V-to-400V prototype. From the experimental results, the proposed converter can provide a voltage gain of 16 under an input current ripple of 25% with an efficiency of 96.3%.