Study On Control Of Chaos And Bifurcation In Current-Mode Controlled SEPIC Converter

In recent years, the study of nonlinear behaviors in DC-DC switching converter has been made many substantive progresses. Through the extensive and in-depth research in theory, simulation and experiment, confirm that DC-DC converter can exhibit abundant dynamic phenomena under some condition, such as bifurcation and chaos. However the study of nonlinear chaos phenomenon in high order SEPIC converter has a late start at home and abroad, and research results of bifurcation and chaos phenomena in SEPIC converter are rarely reported in recent years. In this paper the current-mode controlled SEPIC converter is chosen as research object, and the study of bifurcation, chaos and chaos control in SEPIC converter are carried out, then confirmed by circuit simulation, theoretical analysis, and experiment.To begin with, the background of this research is introduced, and generalizes the research situation of the nonlinear chaos phenomena of SEPIC converter, then points out the deficiency in this research field. Then introduces the commonly used control method and nonlinear analysis method in the nonlinear study of DC-DC converter, and put forward a kind of drawing method of bifurcation diagram. The method is combining simulation data with Matlab to draw the bifurcation diagram which represents nonlinear system dynamic characteristics. Further on the study of current-mode controlled SEPIC converter is carried out, the operating principles of SEPIC converter working in continuous and discontinuous conduction modes are analyzed. Under different conducting mode the discrete time models are established separately, and the stability of fixed point is analyzed. By circuit simulation, circuit experiment and theoretical analysis, bifurcation phenomenon in SEPIC converter under both conduction modes is confirmed. In the process to chaos the occurrence of bifurcation behavior makes SEPIC converter experiences a kind of period-doubling state. The circuit experiences period, double period, quadruple period and then double period, quadruple period, finally entered into chaos. In the end, several kinds of chaos control methods are introduced. The Resonant Parametric Perturbation is applied to control the chaos in continuous conduction mode SEPIC converter, which realizes the control of chaos in SEPIC converter, and the simulation and experiment results are given finally.