Small-signal modeling of single-phase power-factor correcting AC/DC converters: a unified approach

A new small-signal model is introduced for single-phase PFC AC/DC converters. The derived small-signal transfer-functions-based on harmonic analysis-are valid up to half the switching-frequency. Thus it can be used to design a feedback-loop for a system requiring its bandwidth well over twice the line-frequency-such as single-stage PFC schemes. The model can also analyze the large-signal line-harmonics of the closed-loop system. Experimental results and comparisons with classical modeling method are given.