Synchronous Rectification and Parameter Design Based on Accurate Time-Domain Model for Asymmetrical CLLC Resonant Converter

The asymmetrical CLLC resonant converter is a bidirectional isolated DC/DC converter with excellent soft-switching characteristics. However, traditional CLLC converters commonly employ symmetrical analytical methods for synchronous rectification (SR) realization and parameter design, which are not suitable for asymmetrical CLLC resonant converters. Therefore, this paper proposes an accurate time-domain modeling method suitable for asymmetrical CLLC resonant converters to achieve precise SR and wide voltage regulation range parameter design. This time-domain modeling method can accurately compute converter parameters such as SR angles and voltage gain for an asymmetrical CLLC resonant converter under various operating modes. The accurate SR angle data obtained through the time-domain model guarantees that the CLLC resonant converter can achieve SR under different operating conditions. Furthermore, the proposed parameter design methodology ensures that the asymmetrical CLLC converter maintains a wide voltage regulation range while preserving favorable soft-switching characteristics. Finally, the feasibility of the proposed SR method and parameter design methodology based on the time-domain model was validated through a 2kW CLLC resonant converter experimental test bench.