Small signal modeling and analysis of interleaved active-clamp forward converter with parallel input and series-parallel output

The small signal model of an interleaved active clamp forward converter with parallel input and series-parallel output is presented in this paper. With interleaved control schemes for two phases in the proposed combined converter, the second side windings of the transformers can work in series when the input voltage is low while in parallel when input voltage is high. In order to predict the system dynamic behavior and optimize the loop control, the small signal model is derived in this paper. Based on this model the closed loop compensation is designed and the theoretical dynamic behavior is obtained. Finally, the prototype circuit is built. Both the simulation and experiment results are presented to validate the small signal model.