Identification and analysis of nonlinear phenomena in boost PFC converter using bifurcation maps

Abstract

Power-factor-correction (PFC) boost converter is the common choice for a pure sinusoidal current with a near unity power factor. The dynamics of PFC converter can be periodic with line frequency or switching frequency. This paper describes low-frequency instability, which has the practical effect on power factor values. The converter has been controlled using a conventional average-current-mode control to operate at continuous-conduction-mode (CCM). Computer simulations based on nonlinear analysis are performed to study the system stability under the variation of some chosen parameters such as load, output capacitor and feedback gain. Also, the regions of instability phenomena of the PFC converter are delimited, which is of practical interest for engineering design. The nonlinear analysis is constructed mainly from the state-space equation averaged over the switching frequency only. Based on this analysis, new two-dimensional bifurcation maps are provided to give some general outstanding about stability conditions and to identify the stable regions in the parameters space. Moreover, these maps provide an indication about the PFC converter dynamics such as its power factor values and load regulations. Beside, a prototype design of the PFC circuit is introduced to detect these instability experimentally and confirm the simulated result. Results show a good agreement between the numerical analysis and experiment.