Efficiency Optimization Design of L-LLC Resonant Bidirectional DC-DC Converter

The new type of L-LLC resonant bidirectional DC-DC converter (L-LLC-BDC) has merits high efficiency, high-power density and wide gain power ranges, it is suitable for energy interface between storage systems DC micro grid. However, the resonances are sensitive to parasitic parameters, which will deteriorate efficiency. This paper investigates intrinsic mechanism parameters on L-LLC-BDC operating principle working characteristics based analysis modes resonance tank. By taking oscillation produced in stage freewheeling into consideration, a parameter optimization method proposed reduce current while maintaining characteristic natural soft switching. experiment results not only validated design method, but also testified improvement efficiency through minimization conduction switching loss.