A Novel Loop Gain Model of a Single-Phase PFC Based on the D-Q Frame Concept

A proper loop gain design is a good sign of small-signal stability and load transient dynamics. However, the existing quasi-static-based loop gain model for single-phase power factor correction (PFC) converters is imprecise and has application limitations. To address this issue, this article proposes a novel voltage loop gain model based on the
d–q
frame concept. The loop gain model is derived in different formats to be used in a single-phase system, a three-phase three-wire system, and a three-phase four-wire system. The proposed voltage loop gain model is more accurate for the single-phase system than the quasi-static approximation method, which even failed to analyze three-phase systems. The proposed loop gain model reveals the mechanism of how the source dynamics are coupled into the control loops of PFC, filling the gap in analyzing the stability of ac systems with single-phase loads using the loop gain method. The accuracy of the loop gain model is verified through simulations and experiments.