Better EMI filtering/suppression for high power electronics?
Better EMI filtering/suppression for high power electronics?
(OP)
I work for a company that designs and manufactures high power electronics for power conversion/regulation in aircraft. My question was regarding EMI; I wanted to know if there are new, more efficient methods for EMI filtering/suppression. Typically our filtering methods involve adding inductance and capacitance as needed, as well as adding ferrite components as shielding. Weight is a critical point in aviation, so if there are lighter and smaller components/methods, then I'd like to implement them.
Thank you,
Joseph
Thank you,
Joseph





RE: Better EMI filtering/suppression for high power electronics?
2) I assume you are shielding the entire box. If this is the case you may be able to lighten the shield by virtue of the fact that it doesn't need to be solid, but this will require knowledge of the frequency your trying to filter. Think of the shield on the door of your microwave as an example.
3) On the output, you will probably still require a transformer. An Al transformer would be lighter than a Cu one.
4) If increase the switching frequency of your system you can make the magnetic components smaller, but this also increases the losses.
RE: Better EMI filtering/suppression for high power electronics?
RE: Better EMI filtering/suppression for high power electronics?
Would a spread spectrum clock pertain to power electronics for aircraft? I thought that was primarily for telecommunications.
Also, are there any innovative, new ways to handle EMI filtering? We utilize all of the aforementioned methods already, and I'm looking for somthing better.
RE: Better EMI filtering/suppression for high power electronics?
- Curtail it at the source and keep it from leaving your system
- a wide, flat surface will be a lower impedance (inductance) channel than a wire
- don't inadvertently create an antenna.
- high speed signals (as determined by rise/fall time will follow the path of least inductance
- EMI susceptibility is the flip side of the same coin as emissivity. Prevent the latter and you avoid the former
Two great book resources about EMI and noise would be Henry Ott and Howard Johnson's books. Both of these have helped me solve real world EMI and noise issues in an analytical fashion and avoid the guessing games that constitute the normal approach. One thing to remember is that EMI control almost always has to be designed in and it is often times extremely difficult and expensive, if not impossible to correct an EMI issue on a bad design.[li] proper grounding is very important
http://www.amazon.com/Reduction-Techniques-Electro...
and
http://www.amazon.com/High-Speed-Digital-Design-Ha...
RE: Better EMI filtering/suppression for high power electronics?
It's not directly related to the communications technique that shares the name, but there's some common ground in the initial concept of getting away from using a pure carrier/clock.
RE: Better EMI filtering/suppression for high power electronics?
RE: Better EMI filtering/suppression for high power electronics?
Otherwise, I agree with the above sentiment that it is best to use the physical design of the converter to preclude the emission, if not the formation, of EMI in the first place.
RE: Better EMI filtering/suppression for high power electronics?
Detailed design guides with example analysis and data for various shielding materials, apertures, at various frequencies....
You can search and download MIL-HDBK's from the US army Assist webpage.
STF
RE: Better EMI filtering/suppression for high power electronics?
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Better EMI filtering/suppression for high power electronics?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.