Analysis of LLC resonant converter with current-doubler rectification circuit

Abstract

In this paper, LLC series resonant converter with current-doubler as a rectification circuit for secondary side is proposed. The current-doubler circuit is generally used for the high voltage input and low voltage output application to get high efficiency characteristics with reduced transformer turn ratio. However, an inductive circuit is not used in a secondary side for the LLC series resonant converter generally. When there is inductive circuit like current-double on the secondary side, the resonant characteristics are changed. In this paper, LLC converter with the current-doubler using coupled inductor is proposed. We verify that the secondary side current-doubler using coupled inductor is not affect to the resonant characteristic of primary LLC by the mathematical analysis. Finally, the analysis results are proved by the simulation and experiments.