Analysis Of Dynamic Characteristics Of The Flyback Converter Closed-Loop Control System

Flyback converter occupies a key position in the development of switching power supply.DC-DC converter working on a periodically switch operating mode and present a strong nonlinear phenomena, such as period-doubling bifurcation, Hopf bifurcation and chaos status. In practical applications, through the design of different types of compensating network constitute a closed-loop system to improve the work performance of the converter system. The selection of controller circuit parameters may have effects on system stability. So, necessary analysis and research would contribute to the optimization of control parameters and reveal the nature of nonlinear phenomena of this kind of converter system.This paper analyzes the dynamic behavior in the PD and PI controller for flyback converter closed-loop control system. Firstly, with the help of the closed-loop transfer function and the characteristic root method, the relationship between the value of control parameters and system stability is derived by Circuit stable gain guidelines criterion and Routh criterion. Secondly, building flyback converter circuit under the PD control circuit model by discrete time mapping method and the improved PI control circuit model by average method. The controller parameters as the bifurcation parameter to analyze changes of the system through period-doubling bifurcation and Hopf bifurcation to chaos status. It will determine control parameters stability value range and defined impact of proportional component on system stability. Finally, it will verify in simulation and experimental platform, confirming the correctness of the theory.