Dual-Mode Bidirectional <i>LLC</i>-DAB Converter Based on a Modulated Coupled Inductor
Xiaoying Chen, Guo Xu, Hua Han, Yao Sun, Mei Su
Abstract
The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter and dual-active-bridge (DAB) converter are attractive topologies to be used in bidirectional power applications for their respective advantages. In this letter, a dual-mode bidirectional <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> -DAB converter based on a modulated coupled inductor is proposed to combine the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> and DAB converter into a single converter. By only modulating the PWM signals, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> tank of the converter in two operation modes can be changed without adding any other additional diodes or switches. Meanwhile, by utilizing the modulated coupled inductor, the inductance of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> tank will be different for two operation modes. The small leakage inductance is suitable for resonance with resonant capacitor in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> mode. And the large inductance is adopted to transfer the power in the DAB mode. Therefore, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> tank parameters for two operation modes can be designed separately. The principle of the proposed dual-mode converter based on the modulated coupled inductor is investigated. After that, the parameters design consideration of the converter is given. Finally, a 2000-W prototype is built to verify the effectiveness of the proposed converter.