High Performance Boundary Control of Boost-Derived PFCs: Natural Switching Surface Derivation and Properties

This study presents the application of the natural switching surface (NSS) to control single-phase 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 provide valuable graphical insight and 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 switching surface (SS) provides fast output voltage regulation and input current dynamics, 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 simulation and experimental results of a 300 WPFC.