Wide Voltage Input Full Bridge(FB)/Half Bridge(HB) Morphing-Based LLC DC–DC Converter Using Numerical Optimal Trajectory Control

Full-bridge/half-bridge (FB/HB) morphing topology is very suitable to be used in a wide input voltage range for an LLC dc–dc converter. To improve the dynamic performance in facing the input voltage variation, a numerical optimal trajectory control is presented. The power circuit considering its parasitic parameters is simulated first and the simulated data can be stored in DSP memory. These discrete data can be used to obtain the accurate gain-frequency curve versus different loads by numerical methods. The proposed numerical optimal trajectory (OTC) can achieve a very fast and smooth transition between FB/HB in facing the input voltage variation. A 640 W 220–760 V input/400 V output LLC resonant converter is built. The effectiveness of the proposed numerical OTC has been verified by the simulation and experimental results.