Small signal parameter of LLC converter

This paper presents the influence of circuit parameters on the small signal characteristics of the control to output transfer function of the LLC current resonant converter. The equivalent source model is employed for the analysis. To derive the dc gain and the internal resistance, circuit simulator is used. The iron loss that increases as the output current increases is considered in order to obtain more accurate results. The experiments are conducted that are in good agreements with the analytical ones. As a result, the major influence of the characteristic impedance on the internal resistance is found out.