Analysis of PFC converter stability using energy balance theory

Abstract

In this paper, the stability problem is studied from the energy balance point of view. For any periodic system, the balance must be occurring in every period, and for any disturbance which occurs the system must operate in the direction of damping this disturbance. One of the most practical examples is the boost PFC converter with average-current-mode control. It is suitable structure to draw input current with a near unity power factor. The main feature of this circuit is the bulk capacitance and using two control loops and multiplier in control circuit that assures its nonlinearity. PFC stability is interpreted as a condition in which the system operating in the expected periodic regime. Then, all those Subharmonic, quasi-periodic, period doubling, chaos considered undesirable and should be avoided. Two nonlinear phenomena are counted in PFC circuit, period doubling bifurcation (occurs first) and chaos. This paper addresses a study for the borderline between the stable and unstable regimes based on energy balance theory. The details of the proposed method are introduced and its validity is proved with simulation, experiment and mathematical analysis.