Asynchronous gating strategy for auxiliary-free soft switching in parallel-active interleaved buck converter

Conventional interleaved buck converters frequently rely on bulky resonant networks to achieve soft switching. To address this limitation, this paper proposes a novel asynchronous gating strategy that achieves auxiliary-free Zero-Voltage and Zero-Current Switching (ZVS/ZCS) for parallel-active-switch interleaved converters. By utilising active current commutation, the method dynamically eliminates transition overlaps, fundamentally suppressing switching losses and electromagnetic interference (EMI) without added components. The converter's operating principles are mathematically modelled and supported by frequency response analysis. Comparative evaluations demonstrate the topology lowers total diode current stress by up to 92.7%, yielding a 98.28% peak theoretical efficiency. Furthermore, the design exhibits exceptional thermal robustness; peak switch dissipation is restricted to 1.134 W, bounding uncooled junction temperatures to 95.29°C. A 20-year reliability assessment verifies long-term resilience, confirming 76.49% open-circuit and 4.79% short-circuit survival probabilities. Finally, the theoretical framework is comprehensively validated via MATLAB/Simulink simulations and a laboratory hardware prototype. Experimental results confirm sustained ZVS/ZCS realisation and record more than 96% peak operating efficiency. This validates the proposed gating strategy as a highly reliable, structurally simplified, and efficient solution for step-down dc-dc converters.