Modeling closed-loop input and output impedances of DC-DC power converters operating inside dc distribution systems

This paper derives closed-loop input and output impedances of a number of dc-dc power electronic converters when operating in a dc distribution network. The derived impedances can be used for stability analysis and control design for dc distribution networks. In this paper, first the small-signal model of a power converter operating in a dc power system is introduced and the open-loop transfer functions are derived. Next, the closed-loop model of the converter is assembled based on the open-loop model and the type of the control scheme. Then, the closed-loop impedances are derived from the resulting closed-loop model. Finally, the derived impedances are verified using an experimental prototype converter.