Fast‐scale bifurcation in single‐stage PFC power supplies operating with DCM boost stage and CCM forward stage

Abstract

Abstract This paper describes the fast‐scale bifurcation phenomena of a single‐stage single‐switch power‐factor‐correction (PFC) regulator comprising a boost stage operating in discontinuous conduction mode (DCM) and a forward stage operating in continuous conduction mode (CCM). The two stages combine into a single stage by sharing one main switch and one control loop. Using ‘exact’ cycle‐by‐cycle computer simulations, the effects of various circuit parameters on fast‐scale instabilities are studied. The results are qualitatively verified by experimental measurements. This work provides a clear picture of how the variation of certain practical parameters can render such a circuit fast‐scale unstable. Copyright © 2006 John Wiley & Sons, Ltd.