A new method to extend the soft-switching area of three-phase Dual-Active-Bridge converters

This paper presents a new modulation method aiming to extend the soft-switching area of a three-phase Dual-Active-Bridge (DAB) converter. The converter includes three single-phase transformers connecting in Y-Y fashion. A new degree of freedom is introduced to both inverters to make the current discontinuous. Unlike other customized modulation methods that cause the transformer voltages and currents asymmetric, the propose method can maintain the symmetrical form of the voltages and currents. Thanks to that, the switching stress and dissipation arc distributed equally among transistors. Experimental results confirm the proposed modulation technique.