A Dual Active Bridge DC–DC-Based Single Stage AC–DC Converter With Seamless Mode Transition and High Power Factor
Jiankun Zhang, Deshang Sha, Peisong Ma
Abstract
In this article, a dual active bridge (DAB) based single-stage isolated ac–dc converter is studied. By analyzing the root mean square value of the leakage inductor current, the high-frequency transformer turns ratio is optimized for higher conversion efficiency. Three operating modes of the DAB converter are utilized in the control strategy. The current and the voltage waveforms of these operating modes are analyzed. The control variables, including the phase-shift ratio <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ϕ</i> , the primary side duty cycle <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> , and the secondary side duty cycle <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> are combined based on instantaneous calculation according to achieve boundary zero voltage switching (ZVS). The mode transition is seamless while the switching frequency is constant. Furthermore, the magnetizing inductor of the transformer is designed to help the secondary side switches to achieve ZVS. ZVS conditions and parameter design are given in this article. Besides, a 1 kW prototype was fabricated to verify the effectiveness of the design and the control strategy.