Averaged switch modeling of active-clamped converters

In this paper, averaged switch modeling is applied to predict the dynamic behavior of converters with active voltage clamp. The procedure for deriving a large-signal averaged model, starting from defining the switch network and its waveforms, is described. As an example, a model is developed for an active-clamped SEPIC. The model can be easily implemented in PSpice. The measured small-signal transfer functions of the converter closely agree with the model predictions. Further, the time-domain simulations accurately reproduce the observed waveforms in a rectifier application.