Optimization methodology for efficient LLC resonant converter with power factor correction circuit

High efficiency is required in power conversion circuits. A systematic optimization procedure is presented in this paper to optimize LLC series resonant converter efficiency where the effect of LLC input voltage variation cased by power factor correction circuit is considered. A mode solver technique is proposed to handle LLC converter steady-state solutions under different input voltage conditions. Loss models are provided to calculate total component losses using the current and voltage information derived from the mode solver. A prototype 300W 12V output LLC converter is built using the optimization results. Experimental results are presented.