Winding design of series AC inductor for dual active bridge converters

The ac resistance and parasitic capacitance of the inductor are the primary considerations in the winding design for the dual-active bridge converter (DAB). They are dependent of up to four independent structure variables. The interactive restrictions between those variables makes the design difficult. In this paper, the core-related capacitances between the central limb, side limb, yoke and winding are derived, and a local optimization for it is proposed. Moreover, a total winding capacitance design method is proposed by mapping the four dimensional problem into two dimensions. The analysis and design are verified by finite element method simulations and experimental results on a 100 kHz prototype are performed.