EMI-filter-based electromagnetic interference noise measuring and suppressing system

Abstract

The invention discloses an EMI-filter-based electromagnetic interference noise measuring and suppressing system. The system comprises a linear impedance stabilization network, a signal selection module, a noise amplification module, a filter module, an A/D sampling module, a central control module and a serial port communication module, wherein an extraction signal output end of the linear impedance stabilization network passes through the signal selection module and is input into the input end of the noise amplification module; the output end of the noise amplification module sequentially passes through the filter module and the A/D sampling module and is in two-way connection with the central control module; the central control module communicates with an upper computer by virtue of the serial port communication module; the signal selection module comprises a noise separation circuit and an external relay normally-closed contact K1-1, a relay normally-opened contact K1-2 and a relay normally-opened contact K2-1; the relay normally-closed contact K1-1 and the relay normally-opened contact K1-2 serve as mutually reverse action contacts. The EMI-filter-based electromagnetic interference noise measuring and suppressing system has the advantages that the data can be sampled and regulated, the noise modal is quickly and accurately separated, the external interference is resisted, and the interference of the system on other devices can be simultaneously suppressed.

Description

technical field [0001] The invention relates to an electromagnetic interference noise measurement and suppression system based on an EMI filter, and belongs to the technical field of electromagnetic interference noise processing. Background technique [0002] At present, in power lines and electrical equipment, electromagnetic interference (EMI) is mainly divided into two categories, namely radiated interference and conducted interference. Radiated interference means that the interference source is relatively far away, and the interference emitted by the interference source is absorbed in the form of electromagnetic waves, while conducted interference means that the interference source is relatively close, and the interference source enters the interfered device through coupling capacitance, coupling inductance and public impedance. In the low frequency range, the main form of electromagnetic interference is conducted interference. Interference signals are mainly harmonic c...

AI Technical Summary

Problems solved by technology

Conducted electromagnetic interference measurement system in accordance with international standards adopts linear impedance stabilization network (LISN), which can only provide mixed interference signals of common mode and differential mode superimposed on each other on the power line, because different mode signals determine different filtering performance and topology Therefore, the linear impedance stabilization network used at this stage is not very helpful for the interference suppression of the reagent power line filter

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