In this paper, an isolated bidirectional converter is proposed for transportation applications such as midsize electrified airplanes. Using time-domain analysis a modulation scheme is suggested that allows the converter to transfer any power level up to the nominal value over the entire wide dc range of terminal voltages. A single robust and low cost passive auxiliary is introduced to guarantee zero voltage switching of all the eight switches for any combination of dc voltage and power levels. Effectiveness of the modulation scheme in achieving zero current switching was experimentally confirmed.