A Generalized Analytical Gain Model for CLLC Resonant Converter with Asymmetric Parameters

The CLLC resonant converter is a promising high-frequency bidirectional isolated DC/DC topology due to its inherent soft-switching capability and low circulating energy at nominal condition. Nevertheless, up to now, no simple and accurate gain model for $C L L C$ converter with asymmetric resonant tank parameters is available. This paper proposed a simplified analytical gain model for frequency-modulated $C L L C$ converter based on operation modes analysis and charge conservation law. By decoupling the state-space equations, the proposed model can easily extend to asymmetric resonant tank parameters. Furthermore, a straightforward method to determine upper gain boundary is also proposed in this paper. Finally, the proposed gain model was verified by PLECS simulation results and reported experimental results.