One method to optimize LLC converter

This paper introduces the LLC converter optimization based on two level approaches. The first level is to achieve minimum reactive energy in the resonant tank using FHA. The second level is to select LLC set of parameters in the neighborhood of the FHA minimum reactive energy point and maximize efficiency. The key variable used in the optimization is borderline operating frequency fo, between inductive and capacitive mode of the LLC converter. The borderline frequency will be determined as such to provide the minimum RMS currents and conduction losses. LED driver is given as an example.