Dynamic modeling of a single-switch power factor correction circuit

A PWM switch large signal model for a flyback converter having arbitrary transformer polarity is presented. This model will preserve the input-output property regardless of the transformer polarity. A small signal model for a novel one-stage, switched-mode power factor correction (PFC) converter is also presented in this paper. The model is obtained by applying the small signal perturbation technique to the circuit equations derived from the state-space averaging method. It is shown that this converter exhibits the characteristics of a second order low-pass system for the output-to-input transfer function, and that of a combined second order low-pass and band-pass system for the output-to-control transfer function. The validity of the derived mathematical model was verified by the given experimental results.