Different Frequency Instabilities of Averaged Current Controlled Boost PFC AC-DC Regulators

In this paper we use a new discrete time model of a boost power factor correction (PFC) AC-DC circuit under fixed frequency average current control to obtain dynamical behaviors of the system at different scales of frequency. This system is characterized by two different forcing periods and thus by two different scales of time. Four different kinds of standard instability phenomena are possible depending on the parameters of the circuit. All these instabilities are detectable by using the obtained nonlinear discrete time models. A combination of more than one instability phenomenon is also possible. We put in evidence most of the nonlinear phenomena that could occur in the system by using the switched circuit-based model and we give a unified discrete time model that is able to predict accurately these phenomena. This model is presented to study the stability of the system at different scales of time