The smart energy router (SER) can act a crucial role in the future smart gird system especially when distributed renewable energy resources are taken into consideration. A typical three phase SER consist of three stages, namingly the input stage, the isolation stage and the output stage. Among them, the isolation stage mostly adopts the input-series-output-parallel (ISOP) connected dual active bridge (DAB) topology. In this paper, an accelerated model for the isolation stage of SER is proposed. All the analysis is based on a 1 MVA, 10 kV ac, 750 V dc prototype. The validity of the proposed model is verified by simulation.