DC-DC converters with interphase transformer are commonly used to achieve high power density levels and high efficiency. The interleaving technique produces an increment in the ripple frequencies, reducing passive components weight and size; while an increment of phases leads to a higher power density; nevertheless, a controller is required to prevent current imbalances. As a preliminary step in the development of the control of such complex designs and to understand the dynamical limitations of a highly interleaved converters, a model should be obtained. In this paper, two average models of a six-phase dual-interleaved Buck-Boost converter are developed using an averaged switch circuit approach. Time domain tests along the frequency response of the system are used to evaluate the performance of the models using Saber simulations as a reference. The models are evaluated under nominal and extreme operating conditions.