Research On Integrated Suppression Method Of Mixed EMI Noise Based On Conducted Disturbance And Radiated Disturbance

With the constant development and advancement of high-frequency electronic devices in recent years, the issue of high-frequency electromagnetic interference(EMI)in power cable lines tends to be more prominent. Hence, designing high-performance filters becomes the challenge to me meet. Based on practical engineering EMI rectification cases, this paper proposes a new idea of integrated mixed noise suppression,which differs from previous separate studies on conducted EMI disturbances and radiated EMI disturbances. Theoretical analysis and application research on integrated EMI filters used in power cable lines are conducted as follows.(1)Basic theoretical research on integrated EMI filters used in power cable lines is conducted. Through analysis of both conducted EMI and radiated EMI models,mechanism of suppression of these two kinds of interference is obtained. Power lines in complicated electronic devices are classified as AC power lines, DC power lined,digital control lines and sensor lines. Mechanism of radiated EMI noise of these four types of power lines is obtained and corresponding far-field models are established.Due to coupling effects, all sorts of radiated EMI noise generally overlay on the AC power lines. For this reason, AC power line becomes the effective and feasible rectification spot and main filter spot.(2)The structure of integrated EMI filters used in power cable lines is designed, in which an radiation filter is added to the conduction filter. For radiation filters, frequency of EMI noise is divided into three spectrum, i.e low-frequency, medium-frequency and high-frequency, and structures of a combination of inductors and capacitors, magnet ring and metal tubes are used correspondingly to suppress the EMI noise.(3)Comprehensive application research are conducted on the integrated EMI filter applied on power supply cables. Based on the proposed idea in this paper, three electronic products are experimentally verified through the integrated filter design. A-nalysis and suppression process of conducted and radiated EMI disturbances are descr ibed in detail respectively. In the case of Sodium sulfur storage converter communication module, a capacitor is adopted. In the case of Sputum aspirator, an integrated filter made up of inductors, capacitors and magnetic rings is installed. In the case of Meridian guiding therapeutic instrument, an integrated filter made up of capacitors, magnetic rings and metal casing is installed. Testing results of the above three rectifications meet corresponding standards and prove to be effective and feasible,which lays the foundation and provides theoretical and practical references for future engineering application of conducted EMI noise suppression.