| Summary: | 碩士 === 龍華科技大學 === 電機工程系碩士班 === 100 === This study investigates the nonlinear behavior when the switching frequency change in the UC3842 current-mode controlled flyback converter. First, State equations and discrete-time analytic solutions of the flyback converter are derived. The converter in continuous conduction mode is considered. Second, MATLAB/SIMULINK and IsSpice are used to construct simulation of the converter whose operating under vary 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 and IsSpice provide consistent results and verify the mathematical models and able to really understand the nonlinear behavior of the flyback converter.
Finally, the actual circuit is implemented and measured the waveform form the period-doubling bifurcation to chaos by changing the switching frequency of the flyback converters which verified the accuracy of the theory and simulation.
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