Reduction In EMI Of DC-DC Switching Converter Using Chaos Theory

The study of nonlinear chaos phenomena in DC-DC switching converters is now becoming more and more popular in Electrical and Electronics field. Do some research for this complex and mysterious phenomena will not only be especially worthy, but have a profound significance in industrial application. Since the limited research method of chaos analysis in Power Electronics, the advantages of chaos application can not be shown well for us. As a result of that, this paper has studied deeply in the aspects of the S-switching chaotic modeling, analysis of bifurcation, control of chaos and discussion of some applications of chaos in DC-DC Buck converters, such as, chaotic self control and improvement of EMC by chaos. Further more, experiment circuit has been done to prove the simulation and analysis.In this paper, firstly, the precised discrete iterate S-switching mathematical map model is proposed for Buck converter under continuous current mode. And the advantages of discrete iterate model have been shown compared with the conventional linear average model.And then, based on the model, the author uses the Simulink module and M. files in the software of Matlab to establish an S-switching iterate model of Buck converter. The stability of the system and phenomena of bifurcation and chaos are studied by using five different classical chaotic stable criterions, which develop the fruit of former researches in this field. In addition, the experiment of Buck converter reveals the correctness of the model.At last, self-excitation-chaos control method is used to suppress EMI in switching converter. This method spreads the power spectrum density of the converter. And the optimized and improved plans, which include chaos orbits stabilization and chaos PWM modulation, are used to avoid the disadvantages performances of Buck converter during the period of self-excitation-chaos. The experiments illustrate that: chaos theory is one of the useful theory to improve the EMC of switching converters. And the circuit even has better performances in the reduction of EMI when it is working in chaos.