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Forum Index : Electronics : Good money after bad - Solar upgrade time

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wiseguy

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Joined: 21/06/2018
Location: Australia
Posts: 1192
Posted: 09:16am 29 Apr 2025
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I have seen and experienced this exact phenomena, I consider it to be a nuisance type issue. I put it down to random probably nano/pico second differences in the nano just executing the code. If enough of these slight perturbations occur in the same direction ie always on the positive cycles the Toroid Flux wanders towards (very mild) saturation on one side of the half cycles but eventually it slowly wanders back the other way. Sometimes there is no noise for multiples of minutes, even tens of minutes but it is never gone.  The corresponding slight increase in current during the mild saturation would also be expected. The reason this does not continue on to become a real issue is that the slight error causing it means there is not enough energy in the error to put it into greater saturation.

Note a toroidal transformer in an amplifier or similar device can make a hell of a "boing" sound followed by a few cycles of hum that decreases rapidly, if you catch it on the wrong part of the cycle after a turn off turn on event.  I mention this to illustrate that the tendency of a transformer is to try to reach a level of equilibrium after an upset, maybe the AC has a natural tendency to demagnetise & remove any saturation naturally.

The Power PCB FET holes were made to accommodate a standard 3.6mmOD TO220 Bush, and with the long necked variety yes the bush shoulders continue into the TO247 FET hole. Something similar to the Digikey part 12SWS0400, it is better not to have to drill out the circuit board plated through holes....
Edited 2025-04-30 00:10 by wiseguy
If at first you dont succeed, I suggest you avoid sky diving....
Cheers Mike
 
oreo

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Joined: 11/12/2020
Location: Canada
Posts: 95
Posted: 12:07am 30 Apr 2025
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  wiseguy said  I have seen and experienced this exact phenomena, I consider it to be a nuisance type issue. I put it down to random probably nano/pico second differences in the nano just executing the code. If enough of these slight perturbations occur in the same direction ie always on the positive cycles the Toroid Flux wanders towards (very mild) saturation on one side of the half cycles but eventually it slowly wanders back the other way. Sometimes there is no noise for multiples of minutes, even tens of minutes but it is never gone.  The corresponding slight increase in current during the mild saturation would also be expected. The reason this does not continue on to become a real issue is that the slight error causing it means there is not enough energy in the error to put it into greater saturation.


Interesting.  Thanks for the update Mike!
Greg
 
analog8484
Senior Member

Joined: 11/11/2021
Location: United States
Posts: 129
Posted: 05:10pm 30 Apr 2025
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  oreo said  Well for the transformer I basically connected the original primary and secondary in parallel and called that my HV winding, and then added a new LV winding.  So that kind of makes the transformer into a 3KVA transformer. (other 3KVA transformers are very similar in weight to my rewound transformer)  IMO cooling makes a big difference, and I am passing air through the center of the core, and forcing it closely to the walls of the transformer.  Plus the fans I am using move a lot of air and the LV winding has very thin insulation on it which should result in better heat transfer.  Further testing is probably in order though.


Thanks for the explanation. I was wondering because I've seen quite different ratings from different manufacturers for similar size/weight transformers.
 
analog8484
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Joined: 11/11/2021
Location: United States
Posts: 129
Posted: 05:43pm 30 Apr 2025
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  oreo said  

So I made a video and put it in a drop box which you should be able to access here.
The testing was done with no load, and a single 1500w resistive load across 240v
(turn your devices volume to max)


Thanks for the video.  It sounds like some kind of harmonic resonance.  Especially odd that it happens under load.


  oreo said  
Two other items of note.
1.  When I set the inverter to 50hz, I waited for 15 minutes at idle, and did not hear/see any fluctuations in noise or current.  The power was higher, sitting at about 20w continuous.  At 60hz, the noise started fluctuating after about a minute or so of power up.


Not sure if it makes a difference but I remember seeing the timer resolution in the Nanover is relatively low and accuracy for 60Hz is not as good as the 50Hz config.
 
analog8484
Senior Member

Joined: 11/11/2021
Location: United States
Posts: 129
Posted: 05:48pm 30 Apr 2025
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  wiseguy said  I have seen and experienced this exact phenomena, I consider it to be a nuisance type issue. I put it down to random probably nano/pico second differences in the nano just executing the code. If enough of these slight perturbations occur in the same direction ie always on the positive cycles the Toroid Flux wanders towards (very mild) saturation on one side of the half cycles but eventually it slowly wanders back the other way. Sometimes there is no noise for multiples of minutes, even tens of minutes but it is never gone.  The corresponding slight increase in current during the mild saturation would also be expected. The reason this does not continue on to become a real issue is that the slight error causing it means there is not enough energy in the error to put it into greater saturation.


Not sure if it's still used in the latest Nanoverter code but I remember seeing a simple fixed correction for half-cycle balance that is supposed to be tuned for each inverter?  Perhaps that's at play here.
 
KeepIS

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Joined: 13/10/2014
Location: Australia
Posts: 1813
Posted: 01:56am 01 May 2025
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  analog8484 said  Not sure if it's still used in the latest Nanoverter code but I remember seeing a simple fixed correction for half-cycle balance that is supposed to be tuned for each inverter?  Perhaps that's at play here.


You are going back to the early code development days and "per inverter" would imply a kludge, obviously nothing like that here.

  Quote  Not sure if it makes a difference but I remember seeing the timer resolution in the Nanover is relatively low and accuracy for 60Hz is not as good as the 50Hz config.


I assume you are referring to stability, so no, both are stable and adjustable slightly in frequency (in mine)  

There will be small differences between 50Hz and 60Hz with a given Toriod, however if it's wound correctly you should see no real difference in operation, maybe slightly lower idle at 60Hz.
NANO Inverter: Full download - Only Hex Ver 8.1Ks
 
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