Guru
Joined: 13/10/2014
Location: AustraliaPosts: 1727
| Posted: 07:57am 24 May 2024 |
Because I'm removing inverter induced RF from the Controller. This noise is on the board cables that run from or near the main inverter input power bus. I'm not trying to stop external radiated RFI from the inverter.
So for this inverter noise, the Main battery NEG connection, either right at the Power board, or very close to it, as is my case, as an equally short NEG cable runs from the Power board NEG up to the main NEG bus connection, just above the controller. This is the RF earth for the Power bus. The earth plane is part of the PCB layers, yes the aluminum plate below it is also a screen for radiated RF from the toroid section below it.
When measuring controller noise, I measure between the negative bus at the power board Neg connection, and various points on the Controller PCB, Nano pins, PSU in and out, etc.
This was the most effective method I found for reducing Inverter switching noise from the Controller.
RF radiation into my Ham rig is mainly from one of my Solar controllers, I'm sure that you shutdown all solar controllers when testing for RFI from the inverter, I have only 1 spike on the Amateur-R sections of the 40m band with the inverter.
However that one solar regulator is a real problem when it's running, it's the same make and spec as the 4 older models, but obviously something is different, perhaps cost cutting from the Chinese manufacture in the later model? It puts RFI right across the band with some "20db over 9" wide spikes.
Don't run a VFD, the lathe VFD kills the entire band with 40db over.
I'm just to busy (or slow) to track it down at the moment
EDIT: BTW any earth connection as shown with a capacitor, always increased the RF noise on the controller board in my setup.
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Edited 2024-05-24 18:02 by KeepIS