Boundary control of boost-derived PFCs using the Natural Switching Surface: Derivation and enhanced properties

This work presents the application of the Natural Switching Surface (NSS) to control Power Factor Correctors (PFCs). The proposed boundary control scheme provides tight regulation and enhanced dynamic characteristics. The analysis is performed in the normalized geometrical domain to avoid inaccuracies and provide generality. Low frequency ripple effects are included as part of the converter reference to improve its behavior in steady state and load transient operation. In addition to the complete characterization of the system, a method to obtain fixed-frequency operation is presented by employing discrete-step references. The resulting SS provides an excellent dynamic response and low input harmonic distortion, achieving steady state in only a few switching actions under sudden load disturbances. The enhanced qualities of the natural SS are confirmed with experimental results of a 300 W PFC.