At low voltage-to-current ratios and high frequencies, the dual active bridge can suffer significant turn-off losses on the high-current side and typical design rules can lead to inductances on the same order as parasitics, introducing significant unpredictability and loss. In this paper, we propose to control a dual active (half) bridge in boundary conduction mode in which the inductor current returns to zero before switching. The control achieves ZCS on high-current side and ZVS on the high-voltage side, mitigating the effect of parasitic inductance and reducing switching loss. Operation over a wide power range is provided by burst-mode control. Experimental results are shown verifying the efficacy of the proposed strategy on a 1MHz 40W DAHB converter.
