The need for controlling the energy more efficiently has motivated the development of more compact, modular and efficient power converters such as the Dual Active Bridge (DAB). This dc-dc converter has been suggested as an important part of several power conditioning systems, such as the Solid-State Transformer (SST) to control the power flow between two power sources. Several topologies have been suggested to operate more efficiently the DAB as the switching frequency increases. An accurate representation of the DAB is required in order to design the control strategy that regulated the power flow. In this paper two DAB topologies, named: phase-controlled CLLC (Capacitor-Inductor-Inductor-Capacitor) and CLC (Capacitor Inductor Capacitor) Resonant Dual Active Bridge (RDAB), are studied and compared. Extensive time-domain simulations are carry out in order to compare and validate the functionality of each model under different operating conditions.