The Design Of A Power Line Conducted Interference Test System

With the continuous development of science and technology, all kinds of electrical equipment have been widely used in various fields of national economy and people's daily life. In the normal operation of these devices also launched out electromagnetic energy that may have adverse effects on other equipment, and causes serious harm, which is electromagnetic interference. In recent years, a large number of power electronic devices produce electromagnetic interference emerging, electromagnetic interference (EMI) is increasingly becoming a serious problem in electronic equipment or system, electromagnetic interference measurement has become a number of technical staff and managers attached great importance to the content.Interfere with their transmission route, mainly along the power line, signal line communication transmission interference, and radiation to the surrounding space launch interference. Conducted interference is an electric disturbance on the network coupled to another electrical network through the conductive medium and measured with the interference voltage (terminal voltage). To measure the device's conducted EMI, the major measurement instruments need to have EMI measurement receiver, the line impedance stabilization network LISN, a variety of voltage and current probes, spectrum analyzers and oscilloscopes. Line impedance stabilization network LISN as an important test equipment, is the focus of this study.This article first do more in-depth research on the conducted interference, analysis and description of the mechanism of conduction disturbance, coupled channels, measuring instruments and testing methods; Followed detailed design of the conducted EMI test equipment hardware, so as to make measurement more accurate power supply EMI filter circuit, L/N line selection circuit, ground protection circuit, instantaneous limiter circuit, and the artificial hand circuit are designed. In order to achieve various functions,89C51 microcontroller with USB interface circuit used to achieve lower computer and PC communication. Finally, use MATLAB simulated each functional circuit and simulation results show the effectiveness of these modules.