Quasi-Single-Stage AC-DC Converter Based on Triple-Active-Bridge Structure With Low-iTHD

In the field of AC-DC power supplies, reducing power conversion stages to improve overall efficiency and eliminating zero-crossing distortion in grid-side input current to enhance power factor and grid-side power quality remain challenges for the industry. This paper innovatively proposes a novel AC-DC converter topology based on a triple-active-bridge (TAB) structure, aiming to eliminate grid-side current zerocrossing distortion. Research results demonstrate that the proposed configuration achieves quasi-single-stage conversion, which achieves a grid-side input current total harmonic distortion (THD) as low as 0.3 % under <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$220 \mathrm{V} / 50 \text{Hz} \text{AC}$</tex> input and 200 V DC output conditions. The input current exhibits smooth transitions near the zero-crossing region, significantly improving grid-side power quality and operational efficiency