Analysis of LLC Resonant Converter for constant voltage applications

With the development of power electronics devices, resonant converter is proved to be more efficient than conventional converter as it employs soft switching technique. Among the three basic configuration of resonant converter, Series Resonant Converter (SRC), Parallel Resonant Converter (PRC) and Series Parallel Resonant Converter (SPRC), the LLC configuration under SPRC is proved to be most efficient providing narrow switching frequency range for wide range of load variation, improved efficiency and provides ZVS capability even with no load. In the proposed system, an hysteresis controller is used along with LLC converter to provide constant output voltage despite wide input voltage variation. The simulation and analysis has been done for full bridge configuration of LLC converter for both open loop and closed loop operation and the results are presented.