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Forum Index : Electronics : Another Inverter Build

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analog8484
Senior Member

Joined: 11/11/2021
Location: United States
Posts: 135

Posted: 05:35pm 18 May 2025

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KeepIS said Heat gun with diode on low setting, single 3 stack inverter.

These kinds of spikes and distortion have always been there in Inverters, in the past this type of garbage equipment could destroy some inverters, they don't bother these Inverters.

I remember that from your posts. The difference I see is the lack of the very sharp and deep divots. I think that's because your inverter is so beefy compared others.

KeepIS said
Feedback goes through a transformer, full wave rectifier and filter,

That's why I was wondering if and how the very sharp and deep but single per half cycle divots actually show in the VFB.

KeepIS

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Joined: 13/10/2014
Location: Australia
Posts: 1843

Posted: 10:39pm 18 May 2025

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Although the screen capture was from a 3 stack toroid, I have tested a single toroid as well and the results are almost the same.

The only thing that shows up at the VFB input to the ADC is a DC voltage.

Because the VFB circuit and the ACV display on the Nano cannot calculate True and Apparent power (LOW % PF) and not being true RMS detectors, they will respond the same to any load that introduces high harmonic distortion, results will be out by a few volts, AC might be 236v instead of 230v, or 224v instead of 230v, and the AC voltage display will be also be slightly out.

99% of the time it's all good, that 1% of very low PF garbage loads are not an issue, and those voltage margins have never been an issue.

Not knowing the bandwidth and sampling limitations of the small DSO means the previous waveforms "may" appear completely different on a higher spec DSO.

IMHO if that waveform with divots was being presented to the VFB Input terminal at the controller PCB, I doubt it would make much or any difference to AC regulation
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Edited 2025-05-19 09:09 by KeepIS

NANO Inverter: Full download - Only Hex Ver 8.1Ks

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