Conduction Electromagnetic Compatibility Testing With The Inhibition Of Key Technology Research

With the development of power electrical technology, the EMC problems are more and more acted. In this paper, the conducted EMI noise test and suppression are researched.Firstly, the characteristic conducted EMI noise test equipment which is artificial mains network (AMN) is researched. The coupling is proposed as a standard to judge the crosstalk between live line and neutral line. The method of scatter parameter is also proposed to test the characteristics of AMN which improve the test accuracy of AMN. Meanwhile, the high frequency parasitic model of AMN is modeling based on high frequency parasitic components. The characteristic of AMN is analyzed in different high frequency parasitic impacted.Secondly, investigation on noise discrimination network (NDN) techniques for conducted EMI noise on power line is done in this paper including optimization of network topology, performance improvement of circuit elements and the parameter extraction of NDN by using S-parameter measurement. Results show that insertion loss of NDN can be improved about 3dB and noise rejection ratio about 15dB with these techniques. Additionally, two experiments about noise diagnosis and suppression for both conductive EMI noise of SMPS and radiative noise of power line communication (PLC) system have been completed by applying the new NDN to show the efficiency of techniques.Lastly, in conducted EMI suppression field, the robustness of EMI noise impedance extraction methods which including current method and voltage method are analyzed in this paper. Simulation and experiment analyze the characteristic of current probe as well as the impacts standard impedance exerting on extraction accuracy of CM noise impedance. In the research of DM noise impedance extraction, Simulation and experiment analyze the influence of extraction accuracy producing on coupling capacitive and filter unit. In addition, it has also accomplished the contrastive experiments both CM noise impedance and DM noise impedance. It is proved by the research results that on the issue of different mode of noise impedance should be employed with respect to the realistic conditions. In this way the results could better guide the design of EMI filter so that conducted EMI noise could be inhibited. Meanwhile, EMI noise impedance extracted by power method is proposed in this paper. The EMI noise impedance can be extracted by power loss after the EUT accessing test system. This method has simple operation and does not need to estimates the EMI noise impedance. Simulation and experimental result shown the effectiveness of this method.