Small-Signal Modeling of LLC Resonant Converters

Owing to the advantages of high efficiency and high power density, LLC resonant converters have been widely used. Generally, in order to design the closed-loop regulator, the small-signal model is necessary. Nevertheless, the small-signal model of LLC resonant converter is usually complex and inconvenient to be used to design regulators. In this paper, a third-order small-signal model of LLC resonant converter is derived, which is simple enough to obtain analytical expressions and conducive to be utilized to design the closed-up regulator. Finally, the accuracy of the model is confirmed by the simulation results.