A novel modulation strategy for improving the voltage gain of a dual-active-bridge converter is proposed herein. Under the strategy, the converter performs a high-voltage gain under a low transformer turns ratio, thereby improving the transmission efficiency of the transformer because the large turns ratio typically results in large parasitic parameters, such as leakage inductance or distributed capacitance. In addition, voltage spikes can be avoided as the energy caused by leakage inductance is recycled to the output side. The operating principle of the proposed modulation strategy is discussed in detail herein. Moreover, the zero-voltage switching conditions in both buck and boost modes are analysed and derived. Finally, a prototype with a 350 V high voltage, 48 V low voltage, and 1 kW output power is established, and the conversion efficiencies of 94.2% in buck mode and 93.2% in boost mode are obtained. Experimental results verify the validity of the proposed modulation strategy.

中文翻译：

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改善双有源桥转换器电压增益的调制策略

本文提出了一种用于改善双有源桥转换器的电压增益的新颖的调制策略。在该策略下，转换器在低变压器匝数比下执行高压增益，从而提高了变压器的传输效率，因为大匝数比通常会产生较大的寄生参数，例如漏感或分布电容。另外，由于漏感引起的能量被循环到输出侧，因此可以避免电压尖峰。本文详细讨论了所提出的调制策略的工作原理。此外，分析并推导了降压和升压模式下的零电压开关条件。最后，建立了一个具有350 V高压，48 V低压和1 kW输出功率的原型，降压模式下的转换效率为94.2％，升压模式下的转换效率为93.2％。实验结果验证了所提出的调制策略的有效性。