A study of nonlinear controllers for AC/DC boost PFC converters

Front-end AC/DC single-phase converters in typical two-stage AC/DC converters are typically implemented with linear controllers that allow them to perform input power factor correction (PFC). Such conventional PFC controllers generally have a very low bandwidth voltage loop to filter the 2^nd harmonic DC bus ripple, but this loop results in from poor dynamic performance. In this paper, a comparative study of three nonlinear controllers is made. The basic principles of each controller are explained and results from prototypes of converters with each controller are presented. Based on these results, conclusions are made about the effectiveness of each controller relative to the other nonlinear controllers.