Bifurcation Analysis of Slow-Scale Oscillation in SIDO Boost PFC Converter Using Time-Frequency Characteristic Representation Method

Besides line frequency excitation, strong nonlinear crossing effect amongst three input/output ports exists in single-inductor dual-output (SIDO) boost power factor correction (PFC) converters, which leads to the occurrence of complex behaviors including slow-scale oscillation. In this brief, a nonlinear averaged model is derived to describe the nonlinear time-periodic coupling (NTPC) effect of the SIDO PFC converter, and importantly time-frequency characteristic representation method is proposed to obtain the analytical expression of periodic equilibrium solutions. Furthermore, two types of slow-scale oscillations are identified with the help of the loci movement of Floquet multipliers. It is shown that period-doubling bifurcation and Hopf bifurcation are responsible for type I alternating peak oscillation and type II discontinuous trajectory oscillation, respectively. Especially, Hopf bifurcation results in one incommensurable frequency component with respect to the line frequency, which explains the reason why the system enters one quasi-periodic orbit. Finally, these experimental results are given to verify the theoretical analysis. These above results are beneficial to guide circuit optimal design.