Enhanced DAB for Efficiency Preservation Using Adjustable-Tap High-Frequency Transformer
Enhanced DAB for Efficiency Preservation Using Adjustable-Tap High-Frequency Transformer
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DOI：
10.1109/tpel.2019.2958632
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发表时间：
2020-07-01
影响因子：
6.7
通讯作者：
Matioli, Elison
中科院分区：
文献类型：
--
作者：
Jafari, Armin;Nikoo, Mohammad Samizadeh;Matioli, Elison
具有宽范围电压调节的高效DC-DC功率转换对于可持续和鲁棒的电力电子系统至关重要。双有源电桥（DAB）提供直接调节，其Transformer可实现许多应用所需的电压升压/降压，例如电池充电器和直流配电系统的总线转换器。然而，在轻负载下或在远离匝数比的电压增益下工作时失去软开关会严重降低DAB的效率，特别是在高开关频率下。在这篇文章中，我们展示了一种增强型DAB（E-DAB）拓扑结构，该拓扑结构采用可调抽头Transformer，以在更宽的电压增益范围内扩展软开关，并增加功率传输能力。通过适当的抽头调整和单相移调制，所提出的氮化镓（GaN）基转换器实现了97.4%的峰值效率，其总体效率大于传统DAB，电压增益高达2.8倍。采用具有300 kHz集成漏感的准平面矩阵Transformer，可实现10 kW/l的极高功率密度（冷却时为7.5 kW/l）。分接的Transformer不会对拓扑产生额外损耗。推导了E-DAB软开关工作时的增益与功率传输特性，并在宽功率范围内验证了其效率的提高。
Efficient dc-dc power-conversion with wide-span voltage-regulation is crucial to a sustainable and robust power electronics system. Dual-active-bridge (DAB) offers straight-forward regulation and its transformer enables voltage step-up/down required for many applications, such as battery chargers and bus converters for dc distribution systems. However, losing soft-switching at light loads or when operating at voltage gains far from the turns ratio severely degrades the efficiency of DAB, especially at high switching frequencies. In this article, we demonstrate an enhanced DAB (E-DAB) topology which employs an adjustabletap transformer to extend the soft-switching over wider voltage gains and increase the power-transfer capability. By a proper tap adjustment and with single phase-shift modulation, the proposed gallium nitride (GaN)-based converter achieved a peak efficiency of 97.4% with an overall efficiency greater than a conventional DAB for voltage gains of up to 2.8 times higher. Employing a quasi-planar matrix transformer with integrated leakage inductance at 300 kHz allowed for an extremely high power density of 10 kW/l (7.5 kW/l with cooling). The tapped transformer did not incur extra losses to the topology. The gain versus power-transfer characteristic for soft-switching operation was derived for the E-DAB and its improvement in efficiency was experimentally verified over a wide power range.