Research On Suppression Of Conducted EMI In Switching Converters

Switching converters are widely used in communication, control, computer and other fields because of the advantages of their small sizes, high efficiency and light weight and a large power factor. However, when switching converter is working in a high frequency state, it can produce a transient pulse containing high frequency harmonics that can emit electromagnetic interference, electromagnetic interference can cause pollution to the network and direct impact to other electrical appliances to work by conduction, radiation, so researching the mechanism of electromagnetic interference with the switching converter and suppression technology is great significance.Taking Boost Converter for the study this paper, analyzed the generation mechanism of conducted electromagnetic interference, this paper work completed:1. Designed the RCD, RC buffer circuit, reduce the higher change rate of voltage and current produced by the switching research technology about suppressing common mode signal by a inductor, reduce voltage and current spikes produced by energy storage inductor, simulation results show that methods can suppress electromagnetic interference effectively.2. Research filter technology of the converter electromagnetic interference.Designed electromagnetic interference filters by estimating the source impedance, impedance matching and insertion loss of the filter to select the appropriate network structure. Experimental results show that electromagnetic interference filters can suppress conducted electromagnetic interference of switching converter to reach the standard value.3. Research the peak current control and the OGY chaos control to suppress electromagnetic interference technology, ensure that the same total energy of the circuit and no affecting the performance of the converter and to reduce levels of electromagnetic interference in taking the initiative from the mechanism.Peak current method by adjusting the Upper and lower reference current,controls the converter work in the chaotic state to suppress electromagnetic interference; OGY control method make the reference model of converter in the chaotic state, through sampling inductor current and the reference sampling model in synchronous, and achieve to reduce the level of electromagnetic interference the goals.