Coexisting Fast-Scale and Slow-Scale Instability in Current-Mode Controlled DC/DC Converters: Analysis, Simulation and Experimental Results

This paper investigates the coexisting fast-scale and slow-scale bifurcations in simple dc/dc converters under peak current-mode control operating in continuous conduction mode. Our focus is the boost converter as it is a representative form of dc/dc converter requiring current-mode control. Effects of varying the input voltage and some chosen parameters on the qualitative behavior of the system are studied in detail. Analysis based on a nonlinear simplified discrete-time model, which takes into account the effects of parasitics, is performed to investigate the coexistence of fast-scale and slow-scale bifurcations, and to identify the different types of bifurcation. Boundaries of stable region, slow-scale bifurcation region, fast-scale bifurcation region, coexisting fast and slow-scale bifurcation region are identified. Experimental measurements of the boost converter are provided for verification of the analytical results.