Due to the development of electric vehicles (EVs), recently the research pays more attention to converters in the EV systems. Among the converters, the wide input voltage range converter implemented between the EV battery pack and the auxiliary circuits are discussed. The SiC-based wide input voltage range converter with boost function is implemented in the thesis. Moreover, the operating principles of the resonant converter are studied. In addition, the voltage stress on the resonant capacitor and the current stress through the resonant tank are also analyzed in detail. Finally, the laboratory prototype of wide input range full-bridge (FB) DC-to-DC resonant converter with active-boost rectifier based on SiC power transistors with the input voltage 200-400 V, output voltage 48 V, and rated power 1 kW is implemented. As the experimental results demonstrate, this converter can be operated in wide input voltage range, and the highest efficiency is 91.07%.