Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1191
| Posted: 11:02pm 08 Jun 2024 |
After more thought, that would mean 120W odd watts is going awol (missing) which is a fair bit of energy. If the two voltage readings at no load and under load are different at the connector for mains feedback on the controller board, that is still possible and yet the inverter/servo loop is happy.
The only other explanation I can see is somehow noise is getting into the chain between the precision rectifier input and the VFB at the Nano A0 (pin 19). What I mean is that A0 sees the same feedback voltage for both of the unloaded and loaded conditions that is why the modulation drive % is essentially unchanged.
If this is the case I know you have discovered a huge amount of electrical noise, emanating from the inverter cabinet and into you radio gear, so maybe it is time to look at some noise mitigation techniques. To improve this issue as far as affecting the the controller goes, it can be a combination of noise reduction at the source and also how the noise (or the effect of the noise) induced into the control card can be reduced. An aluminium backing plate ~ 6-10mm from the rear of the controller card is a good first step. The plate does not have to be earthed but the next step is to put a capacitor of at least 10nF from the PCB ground-plane pads to the screw solder pads just near J1.
This makes the plate a Faraday screen to outside noise. It can be grounded no problem but the extra capacitor coupling the ground plane to the plate is a very important part to fit.
The last comment I will make is that if you (or anyone with issues) asks for help, I suggest it is best practice to work with that person and despite for instance 2 or more people wanting to help you, all having different ideas on how to solve it and wanting to go on different paths, you need to decide & announce whose help and advice you want to follow for a time to be fair to all the helper/s. I would be relieved for you to choose to follow for instance KeepIS's advice and I can sit back and observe and maybe even learn something. But when too many cooks get involved pulling you in different directions all asynchronously the landscape (ie noise problem) will keep changing in directions that are hard to keep up with and follow for anyone trying to understand or help solve the same problem. Others may have "stuff" they could or should be doing and therefore multiple people are not all spending time and resources designing the same wheel.
I would be one of the first to say ok I need help here if no progress is being made. But what seems like no progress at first may not be the case as every step that does not have the desired outcome is eliminating sections of circuitry or wiring, and I would like to think homing ever closer to the real cure. Edit: I am not saying any advice you have received to date is wrong or on the wrong path but more to focus on one path at a time is usually less confusing. And making one change at a time not multiple changes as then we can better detect what step actually fixed it or started us in the right direction.
Edited 2024-06-09 11:33 by wiseguy