Transformer Leakage Inductance Selection for Single-Phase Dual Active Bridge DC/DC Converters

The leakage inductance of the transformer in a dual active bridge (DAB) DC/DC converter directly impacts the ac current waveform, power factor, and its performance. In this paper, an analytical formula is derived to determine the optimal leakage inductance for a DAB power level controller to a given rated power. This leads that the reactive power of the fundamental components is kept to zero in all load conditions. The proposed approach allows the DAB converter to operate more than twice as much power density as conventional methods. The presented method can be applicable to a wide variety of DAB applications such as electric vehicles, asynchronous micro-grid interconnection, and aerospace applications, etc.