My understanding of radiation coupling is that it is not a distinctive source separate from SMPS harmonics, but rather a bypass mechanism that can happen if the filter elements are not laid out carefully. The best fix for this, likely only available in a military design, is an EMI doghouse, a metal container over the inside of the power connector that mounts EMI filter elements such that noise generated within or outside the equipment cannot bypass the filter elements.
---------- >From: "Muriel Bittencourt de Liz" <[email protected]> >To: "Lista de EMC da IEEE" <[email protected]> >Subject: EMI Radiation Coupling in SMPSs >Date: Wed, Jul 24, 2002, 9:04 AM > > > Group, > > I was doing some tests of conducted EMI measurements according to CISPR 22, > Class B. This standard uses the 150kHz to 30MHz frequency range. > > The equipments under test (EUT) that I tipically use are switched mode power > supplies (SMPS), mainly with flyback topology. In a number of these SMPS > that I've tested, I found that there are strong peaks about 10MHz-30MHz > frequency range. According to some bibliographic references (books, Web, > papers) these peaks are due to radiation coupling between the elements of > the SMPS, and not due to harmonics of the switching frequency. Another > explanation could be a resonance between accidental L and C (probably > parasitic elements). > > My question is: Would someone give me some advice on these informations?? > Past experiences, papers, comments, WWW addresses... all information is > welcome. > > Thanks! > > Muriel > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > http://ieeepstc.mindcruiser.com/ > Click on "browse" and then "emc-pstc mailing list" > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
