Sample-Data Modeling for Active Clamp Flyback Converter in Critical Conduction Mode with PCM and ZVS control at Variable Switching frequency

Critical conduction mode (CrCM) active clamp flyback (ACF) converter is a good candidate to be applied in low power adaptor applications. Based on sample-data model, this paper proposes an accurate small signal model of variable-frequency PCM and discrete ZVS controlled CrCM ACF converter. In the modeling process, the total current close loop model is decomposed to the linear combination of the PCM and ZVS model. The conduction time of power switch is regarded as the control signal, which is different to constant-frequency converter. In addition, the discrete ZVS control strategy is also considered. To verify the proposed sample-data model, the single PCM model, Suntio’s average model, the SIMPlis simulation and experimental result based on CrCM ACF converter are given. The comparison result show that the proposed sample-data model can fit well with the simulation and experimental result.