It should, normally, but "I think" it's possible as we are dealing with
semiconductors, that on rare occasions it could develop a self resonant
frequency and if it's in a series of cells providing power ??
Theoretically, it's possible for spot contamination along with other
influences to develop a not very efficient transistor. I believe solar
grade Silicon is the least expensive grade but we are still dealing with
a couple parts per billion and even parts per trillion purity. During
fabrication, if a photographic mask slips even a fraction of a mm a
whole batch could develop strange characteristics [ I've been out of the
loop since 87 so I'm not sure what manufacturing process is now being used]
As these appear to be occasional, it's likely caused by a bad batch of
cells.
I've seen the following analogy used to describe parts per billion.
Take a cube of bricks one city block on a side. In this pile are one or
two yellow bricks representing parts per billion.
I heard that CPU fabrication is using X-Rays to get the size down.
One additional point: The semiconductor industry and particularly the
first stage which is the poly-crystal growing stage, is a feast or
famine industry and it is going into one of those shakeout periods.
This means they are really squeezing pennies and at the end of these
cycles there are usually only 3 to 5 poly manufacturers able to survive
73, Roger (K8RI)
On 6/8/2019 11:29 AM, r55stan@gmail.com wrote:
Wouldn't the noise from semiconductors tend to be random (broadband white
noise) in nature? Much like the added noise from an amplifier due to its noise
figure value? The RFI I have experienced from SolarEdge systems falls at
regular intervals in frequency, the harmonics of a switching frequency. As for
choking the optimizers having little effect, there is a good chance they missed
one or more of them. It took four visits at a house 200 feet from me for the
technicians to find all of them. Even a single optimizer without ferrites
makes a lot of RFI.
73, Randy KQ6RS
-----Original Message-----
From: RFI <rfi-bounces@contesting.com> On Behalf Of Roger (K8RI)
Sent: Saturday, June 8, 2019 5:59 AM
To: rfi@contesting.com
Subject: Re: [RFI] SolarEdge Finds New Source of Solar System RFI
Having been involved with the semiconductor industry since early 1961with
everything from poly crystal Silicon growth, single crystal production, to
device production at the experimental, impurity problems, analysis of chemicals
involved, as well as the maintenance and development of that equipment, I can
think of many possibilities that would cause noise generation in individual
solar cells.
73, Roger (K8RI)
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
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
--
Roger (K8RI)
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
--
Roger (K8RI)
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|