The half bridge series resonant converter used for low output voltage power supply applications. This system has soft switching implementation without additional device, high efficiency and compact control. These advantages make this converter promising for high power applications such as auxiliary power supply in the EMU train set. The system consists of hard switched boost chopper, soft switched high frequency inverter based on split capacitors in DC link, high frequency transformer and rectifier. This paper describes several aspects relating to the design of resonant DC/DC converter operating at high frequency and converter topologies are discussed. Simulation and Experiment are performed. These results show that the power electronics converter using resonance DC-DC converter is feasible to the power supply system for EMU train set.