Fast-Scale Stability Analysis of a DC-DC Boost Converter With a Constant Power Load

This article focuses on analyzing the fast-scale stability in a peak current-mode-controlled boost converter with a constant power load (CPL). Since with this kind of nonlinear loads the analytical expression of the discrete-time model is not available and the existing averaged models are inadequate in describing accurately the fast-scale dynamics of these converters, a piecewise linear switched model is established by approximating the CPL by a composite linear load. The model is first demonstrated to predict accurately the same bifurcation points predicted by the switched model using the nonlinear load. The bifurcation analysis using the Floquet theory and the resulting monodromy matrix and its eigenvalues loci clearly show the effect of system parameters on its stability. The fast-scale stability boundaries in terms of suitable parameters are obtained by using eigenvalues analysis. The effect of the proportional gain of the voltage controller is studied. Finally, experimental results are further given to verify the theoretical analysis and simulation results obtaining a good agreement.