Study On The Dynamics Of Boost Converter Based On Chaotic Control Method

In nonlinear systems,chaotic phenomena often occur.However,according to the actual situation,sometimes for the stability of the system needs to weaken or eliminate chaos,and sometimes in order to widen the spectrum characteristics need to enhance or produce chaos,these two cases are called chaotic control and chaotic anti-control.Since chaotic control and chaotic anti-control have been widely used in nonlinear power electronic systems,secure communication,social economics,medical and biological,people have been very interested in the direction of related fields.Since Ott et al.proposed the OGY perturbation control method in 1990,how to control and utilize chaos research set off a boom in the chaotic world.Since then,scholars have shown great passion for chaotic control and obtained a lot of research results.This thesis is mainly based on the previous research of chaotic control and chaotic anti-control methods to optimize and innovate.As a typical switching system,Boost converter is often used as an important research object of nonlinear behavior,so this paper revolves around the Boost converter,and researchs through the composition of different circuit topologies to optimize chaotic and control chaotic systems,respectively,the concrete work is as follows:(1)Ramp compensation is usually used as a means of bifurcation and chaos control,where the ramp introduced is negative ramp.This paper extends it to the chaotic anti-control of the Boost converter,that is,to introduce a positive compensation ramp in order to induce or enhance the chaotic state of the converter system,so as to effectively suppress the electromagnetic pollution phenomenon of the switching power supply.In addition,the system idealized chaotic anti-control is realized by the delay time optimization circuit.Firstly,the amplitude of perturbation ramp is simulated,and analyzed,which mainly includes the evolution of bifurcation phenomenon to chaotic behavior,then the results are verified by discrete iterative mapping;finally the amplitude parameters under better conditions are found according to the simulation data,and the validity of the approach is proved by power spectrum method.(2)On the basis of(1),the fast-scale bifurcation phenomenon of PFC Boost converter is discussed,and the control method is given.Firstly,a simple overview of ramp compensation and ramp formula derivation are introduced;Then,from the point of view of predicting the position of bifurcation point,the ?m of unknown critical phase angle is set on the basis of the known ramp expression,and the corresponding amplitude is calculated according to the ?m.(3)From the perspective of improving power factor,this paper will design a sine wave compensation.The ramp of the sine wave is minimized by tracking the expected working point position of the inductor current through the variable delay phase.At this point,the fast-scale bifurcation behavior in the circuit gets the best control.To verify the optimization of power factor,the waves is simulated separately,ramp compensation and sine wave compensation.The power factor comparison diagram of T changes with converter switching period is analyzed and compared with the power factor uncompensation,ramp compensation and sine wave compensation.