The work in this paper is based on evaluating the optimum design parameters for an LLC converter with topology morphing and synchronous rectification for maximizing overall efficiency. A time domain model is developed for a FB/HB LLC resonant converter with synchronous rectification, and the accuracy is verified against simulation results. A loss model is developed based on the semiconductor and magnetic losses to estimate the converter efficiency. Based on the mathematical model, a design optimization methodology is proposed to maximize efficiency and find optimum converter design parameters (turns ratio, resonant frequency, Q factor, inductance ratio). A design example for an electric vehicle (EV) on-board battery charger (OBC) application is discussed to outline the proposed optimization method.
