Randy-
I've done some testing on the optimizers. If you apply DC to the panel
input leads, the internal switcher will start up and power the internal
microprocessor. However, after that, to put it into operating mode
requires some communications via the output leads from the central
inverter, or a special controller/tool that is not generally available.
Without this command sequence, the optimizer will stay in 'Safe Mode'
where it outputs 1 volt DC. In this mode it is not converting much power
and not generating as much RFI as it normally does in operating mode.
The internal switcher runs at ~200kHz, which explains the spurs commonly
seen at 13.997, 14.197, ... I'm pretty sure this is also the frequency
used on the converter when handling the full load,
Testing in this manner was what allowed me to develop the 3-turn bifilar
choke that is recommended in the QST article. Despite only being able to
test in 'Safe Mode', the chokes were very effective in actual installations.
-Tony, K1KP
On 6/3/2019 12:32 PM, r55stan@gmail.com wrote:
Hi Ed,
I would be interested in anything you discover regarding the interaction
between solar panels and SolarEdge optimizers (DC to DC converters).
I just picked up a SolarEdge optimizer, model P320 on eBay and was planning
to open it up to get a rough idea of how much EMI filtering (if any) it has
on the input and output leads, and also to measure the RFI it generates
feeding it with around 30 VDC from a bench supply. After I am done with it,
I could donate it to you to study.
73,
Randy KQ6RS
-----Original Message-----
From: RFI <rfi-bounces@contesting.com> On Behalf Of Hare, Ed W1RFI
Sent: Monday, June 3, 2019 9:30 AM
To: Wes Attaway (N5WA) <wesattaway@bellsouth.net>; 'Tony'
<dxdx@optonline.net>; 'Tony Brock-Fisher' <barockteer@aol.com>; 'RfiList'
<rfi@contesting.com>; Cianciolo, Paul, W1VLF <pcianciolo@arrl.org>
Subject: Re: [RFI] SolarEdge Finds New Source of Solar System RFI
I will. Tony is pretty good with RFI, but there are always a lot of
variables in residential environments, and we can take the panel to a few
different locations, just to eliminate confounding factors.
Ed
-----Original Message-----
From: Wes Attaway (N5WA) <wesattaway@bellsouth.net>
Sent: Monday, June 3, 2019 12:28 PM
To: Hare, Ed W1RFI <w1rfi@arrl.org>; 'Tony' <dxdx@optonline.net>; 'Tony
Brock-Fisher' <barockteer@aol.com>; 'RfiList' <rfi@contesting.com>;
Cianciolo, Paul, W1VLF <pcianciolo@arrl.org>
Subject: RE: [RFI] SolarEdge Finds New Source of Solar System RFI
Ed .... please keep us posted on results.
-------------------
Wes Attaway (N5WA)
(318) 393-3289 - Shreveport, LA
Computer/Cellphone Forensics
AttawayForensics.com
-------------------
-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of Hare, Ed W1RFI
Sent: Monday, June 03, 2019 11:22 AM
To: Tony; Tony Brock-Fisher; RfiList; Cianciolo, Paul, W1VLF
Subject: Re: [RFI] SolarEdge Finds New Source of Solar System RFI
There are a number of possibilities here.
Yes, the panels themselves could be generating noise by any of a few
different mechanisms. What is not really known is whether this is an
extreme near-field phenomenon, heard only very close to the panel, or
radiated more effectively. Any panel noise could also conduct onto
electrical wiring connected to the panel. A common-mode choke is only going
to be effective if it includes hot, neutral and ground for ac wiring and +,
- and ground for dc.
If the ground lead is not choked off, common mode noise from any source
could be conducted to the panels and radiated from both the conducting
wiring and the panels.
Other noises could be present, confounding any findings.
And, of course, the panels could be creating and radiating noise.
I am going to see if they can send us a panel and microinverter that we can
set up here for testing purposes.
Ed, W1RFI
-----Original Message-----
From: Tony <dxdx@optonline.net>
Sent: Sunday, June 2, 2019 4:28 PM
To: Tony Brock-Fisher <barockteer@aol.com>; Rfi List <rfi@contesting.com>;
Hare, Ed W1RFI <w1rfi@arrl.org>; Cianciolo, Paul, W1VLF
<pcianciolo@arrl.org>
Subject: Re: SolarEdge Finds New Source of Solar System RFI
Tony:
I asked if they were sure about their findings and the answer I got was that
they were still seeing RFI with the system turned off and the array
disconnected and disassembled. I'm assuming disassembled means they removed
the optimizers from the panels.
They found that the noise dropped significantly after they applied ferrites
to the panels, but I'm not sure if they tested a stand-alone panel with and
without chokes or if they ran the test with the system completely
reassembled and turned on. I'll asked that question the next time I speak
with them.
The engineer mentioned the diode theory as well. If there is ambient RF
exciting the panel diodes, is it possible that it would come from the
inverter?
Tony -K2MO
On 6/2/2019 8:51 AM, Tony Brock-Fisher wrote:
Tony et al-
This sounds pretty hard to believe to me. The panels normally contain
no active circuitry, so it's hard to see how they could be generating
RFI.
The panels may have a series diode. Additionally, the cells themselves
are really, really large diodes. The only thing I can think of is that
they could be getting excited by high ambient RF, and then rectifying
that RF to produce harmonics or possibly cross modulation products.
I have an AM BC station that is less than a mile, line of sight, from
my QTH. During the day they transmit at 44kW. I have tons of RF all
over the place, and it does cause lots of products with other BC
stations and AC line modulated direct-diode supplies.
Just my opinion here...
-Tony, K1KP
On 6/1/2019 5:59 PM, Tony wrote:
All:
I recently spoke with an engineer from SolarEdge who said that they
discovered a previously unknown source of RFI which turned out to be
the solar panels themselves. They found that the panels were
producing noise while physically disconnected from the system at a
few installations.
They are now working with the panel manufacturers Hanwha and Trina to
determine why a certain batch of their panels are producing RFI. The
goal is to locate installations with the defective panels and replace
them.
Cumulative RFI from multiple panels is apparently enough to cause
serious RFI and may be the reason why my neighbors installation still
makes noise during?? the day while the system is turned off. It could
also be the reason why the choking the Optimizers had little effect.
Tony -K2MO
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