The only question was: what sort of light source? For EMI concerns, incandescent works best. That¹s all there is to it. No one I know of is arguing to replace the solar array with some other power source. The power source is the luminary that illuminates the solar array, and that can and should be an incandescent for this application.
Ken Javor Phone: (256) 650-5261 From: Edward Price <[email protected]> Reply-To: Edward Price <[email protected]> Date: Fri, 15 Feb 2019 23:15:30 +0000 To: <[email protected]> Conversation: [PSES] Testing a product with that uses a solar panel Subject: Re: [PSES] Testing a product with that uses a solar panel Ken: A long time ago, I used to think there were many things that were patently obvious. As is usually the case, this question has wandered around a bit. At first, the question was whether a solar panel was really needed; couldn¹t the DC power be sourced from a battery or other clean DC source. That answer splits, depending on whether the inverter is a stand-alone black box or perhaps integrated onto the solar panel. Then, the assertion that ³the panel doesn¹t create EMI.² Well, no, it doesn¹t, but it is an array antenna (everything is an antenna), with lots of little conductors and resonant stubs. If you connect this to the input of a buck switching power supply, the current waveform you draw from that solar panel will be inherently noisy. So lets see, we have a non-linear load drawing current from a distributed array of current sources. And, the inverter may be mounted right to the back of the solar cell array, putting he circuit board of the plastic cased inverter maybe a half-inch from the array of solar cells. Predicting that coupling would be an awesome task. I have no idea what might radiate from that solar panel, but it seems anything but obvious. So yes, you can drive the solar panel with photons from an incandescent light (it might be a little off from honest sunlight but were not worried about efficiency). But, if the architecture places a small inverter onto the solar panel and then gangs that with other panels, I think you will need an array of panels in your EMI chamber. Also, I have no idea where along the power curve the inverters may be noisiest, so you may have to repeat testing at low power, medium power and high power just to find the worst-case emission point. And then here¹s another split; are the inverters truly ³integrated into the test sample²? Does the manufacturer mount the inverter in a specific location and provide the hook-up to the array? Or, is it up to the installer to strap the inverter ³someplace² behind the array and under the frame? Ed Price WB6WSN Chula Vista, CA USA From: Ken Javor [mailto:[email protected]] Sent: Friday, February 15, 2019 9:23 AM To: [email protected] Subject: Re: [PSES] Testing a product with that uses a solar panel But the point is the solar panel is integrated into the test sample and must be used as the power source. The only issue is what to use to illuminate the panel. It seems patently obvious to me that an ordinary incandescent bulb (of sufficient power) is the solution for EMI testing. Ken Javor Phone: (256) 650-5261 - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
