Switching frequency influence of flyback converter´s nonlinear phenomena

This paper investigates the nonlinear behaviors when the switching frequency changed in the UC3842 current-mode controlled flyback converter. First, State equations of the flyback converter are derived. The converter in continuous conduction mode (CCM) is then considered. Second, MATLAB/SIMULINK is used to construct simulation of the converter whose operation under varying switching frequency parameters. The output voltage, inductor current waveforms and phase-plane portraits are observed. It can be seen that the system exhibits nonlinear dynamics from period-one operation through period-doubling to chaos phenomena as the switching frequency are changed. From the simulation results, it is clearly evident that SIMULINK provide consistent results and verify the mathematical models and able to really understand the nonlinear behavior of the flyback converter.