Effect of output capacitance time-constant on dynamic characteristics of V2-controlled buck converter

Abstract

The second-order discrete iterative map model of V2-controlled Buck converter is established, based on which, the bifurcation diagrams with variation of output capacitance and its equivalent series resistance (ESR) are obtained, and the effect of output capacitance time-constant on the dynamic characteristics of V2-controlled Buck converter is investigated. It is found that with gradual reduction of output capacitance time-constant, the V2-controlled Buck converter shows the evolutive dynamic behavior from continuous conduction mode (CCM) period-1 to CCM period-2, CCM period-4, CCM period-8, CCM chaos, and discontinuous conduction mode (DCM) chaos. Jacobi matrix at a fixed point is also derived. According to this, the converter stability is analyzed by using characteristic values and maximum Lyapunov exponent, which validates the correctness of bifurcation analysis. Finally, the simulation and experimental circuits are set up, and the correctness of the theoretical analysis is verified by simulation and experimental results.