Transduction Of The Key Issues Of Intelligent Diagnostic Analysis System Electromagnetic Interference

Electromagnetic compatibility is a key research direction in electrical and electronic engineering areas. Though many mature EMC testing standards and suppression methods have been introduced in recent years, numerous conducted EMI problems have been appearing and have not been effectively solved in practical application. In this paper, some key technologies for intelligent conducted EMI diagnosis processing system are researched, and the analysis on conducted EMI noise and processing are combined, in which integrated intelligent process included noise measurement, noise diagnosis, noise analysis, noise suppression and processing is realized. Therefore, research contents in this paper have certain significance in both study and application.Firstly, in this paper, the characteristics of independent component noise measurement network which is used to separate common mode noise and differential mode noise from total noise are researched, and the network is realized by high-frequency transformer or power phase splitter and power combiner (0°/180°) in hardware method. Then, on the basis of index for insert loss (IL) characteristic, common mode rejection ratio(CMRR) characteristic, differential mode rejection ratio (DMRR) characteristic and their frequency response range, noise mode separation technology is improved and optimized, which makes the separation technology stable and reliable and have high technical performance and low economic cost.Secondly, the key technologies for mixed mode noise measurement and extraction in EUT is researched in this paper, which include LISN application and independent component noise measurement network separating different mode noise from total noise in the original transmission line. And on the basis of above devices, noise receiver which is called spectrum analyzer, numerical switching power supply which is noise source and other devices are combined to establish a set of intelligent conducted EMI diagnosis processing system to measure, analyze, calculate EMI noise and realize power filter design.At last, intelligent conducted EMI diagnosis and analysis machine is completed in this paper. In which the main hardware are analog modules which are used to obtain total noise measured by LISN, and get common mode component and differential mode component by independent component noise measurement network, and the digital modules are used to deal with noise signals. Labview virtual instrument development platform of American NI Company is applied to realize software, which include communication function, data acquisition function, EMI noise analysis function, EMI filter design function, EMI noise measurement result input function and testing report printing function. Besides, the practical measurement application on the basis of intelligent conducted EMI diagnosis and analysis machine is realized, and the measuring results verify the effectiveness of the proposed methods in this paper.