The Research To Reduce EMI Level Of New Closed-Loop DC/DC Boost Converter By Controlling Chaos

The EMC problem is a important factor must be considered when a switched —mode power supply is designed. In this thesis we investigate the way to depress EMI in switched—mode power supply in the sourse stage according to. the inherent chaotic phenomenon in itAt the beginning of the thesis , we introduce several usual methods simply to depress EMI and ameliorat EMC of switched-mode power supply. At the same time we analyze the limitation of some traditional methods and the potential goodness of control of chaos to depress EMI of switch-mode power supply.Secondly, we regard DC/DC Boost converter as research object and analyze the harmonic comepoment distribution relationship individually in period, double-period and chaos state.Referring to the spectrum character -ristic of converter through period-doubling bifurcation to the chaos.we confirm the concept in theory that the converter in chaos state has a lower EMI level than that in period state.Thirdly,through the circuit experiment,we analyze and compare the EMI level among new(with maximum-minimum current limited control), prototype(only with maximum current limited control)and constant frequency controlled DC/DC Boost converters.The experimental result demonstrate samely that the new converter works in the chaotic state has a better function to depress EMI.At last, we design a experiential circuit of new closed-loop DC/DC Boost converter with voltage feedback.The analysis of simulation result indicate that the new closed-loop converter can work in chaos state with a stable output voltage.The converter with both voltage and current feedback in this thesis not only has a lower EMI lever, but can keep the output voltage steady. So the analysis result put the research to reduce EMI level of new closed—loop DC/DC Boost converter by controlling chaos on the...