Research On Nonlinear Behaviors And Their Control In Switched-inductor Buck-Boost Converter

With the fast development of power electronics techniques,the nonlinear behaviors and their control in power electronic switching converters have aroused widespread concern.Scholars both from domestic and overseas have endeavored a huge amount of researches on the nonlinear chaos and bifurcation behaviors and their control in power electronic switching converters,and made a series of great academic value achievements.In this thesis,swithed-inductor Buck-Boost converter and their multi-level cascade/parallel type system's nonlinear behaviors and their control are investigated based on scholars from various countries research methods.Swithed-inductor Buck-Boost converter,as a novel switching converter,was proposed in recent years.(1)According to the stroboscopic mapping method,the discrete mapping model of swithed-inductor Buck-Boost converter is derived.Through Matlab numerical simulation,the bifurcation diagram and the poincare section diagram of this circuit system are obatined.With the change of circuit parameters,the evolution law of circuit system's nonlinear dynamic behavior is gained based on the analysis of system Matlab numerical simulation results.Maximum lyapunov exponent spectrum and jacobian matrix eigenvalue are acquired by using Matlab numerical stimulation.According to the structural stability theory of nonlinear system dynamics,the circuit system's stability is analyzed by maximum lyapunov exponent spectrum and jacobian matrix eigenvalue based on the discrete mapping model of system.Simulation module of circuit system is made in Simulink.In order to verify the correctness of the discrete mapping model of circuit system,the corresponding time-domain circuit simulation is taken in Simulink.(2)The discrete mapping model of multi-level cascade/parallel type swithed-inductor Buck-Boost converter is deduced by using stroboscopic mapping method based on individually swithed-inductor Buck-Boost converter's the discrete mapping model.Two-level,three-level,and four-level cascade/parallel type swithed-inductor converter are taken as specific examples.With the increase of the cascade number,variation regulation of system's nonlinear behaviors and their stability are analyzed via methods of Matlab numerical simulation.The corresponding Simulink time-domain circuit simulation of three-level cascade/parallel type converter is made.(3)The nonlinear chaos behavior of swithed-inductor Buck-Boost converter is controled by using two methods currently used in engineering,namely,parametric perturbation method and ramp compensation method.The suitable parameters of pertubation amplitude,pertubation phase angle and ramp compensation current slope are calculated based on methods of theoretical analysis,and Matlab numerical simulation.Finally,the effectiveness of two chaos behavior control methods is demonstrated through Simulink simulations.In conclusion,the results of the nonlinear behaviors and their control in swithed-inductor converter in this thesis have important guidance and reference significance to the design of power electronic switching converter circuits system and the study on the nonlinear behaviors and their control of other types of converter.