Thank you for useful insights. I will implement them in the next version.
Answers to your questions:
(1) Square wave from full H bridge, 45*2 = 90V p-p
(2) Inductors are not installed, ignore them. They were designated to handle a problem which currently doesn't exists.
(3) In past I used...
I managed to overcome the problem. I don't have clear resolution about its root cause, but I found how to eliminate it.
During tests in last weeks (tests for many purposes, not necessary in order to resolve PCB heating) I paid attention that heating of PCB and capacitors strongly linked to...
Yes, I think these current loops are a root cause of the problem.
I doubt that (without heavy simulation) it would be possible to modify trace routing to prevent hot spots created by current loops.
Also I'm somewhat reluctant to remove or cut ground plane. It may resolve eddy current issue but...
Yes, this is one of possible explanations. But presently I don't think it is capacitance coupling issue. There are many wide traces on the board. They all (or most of them) should be hot if capacitive coupling was significant. Furthermore, in that case heating should happen even without load. In...
I think maybe ground plane "smears" the hot spot. For example, if trace on bottom side overheats, it heats the ground plane and therefore we see it as bigger hot spot not exactly aligned with heat source.
Thank you, I will keep these tips as alternative direction if present course of research would not yield expected results. Presently I'm assuming that heating is not due to copper resistance to forward current flow, because this is what calculations, measurements and experiments I did so far...
Thank you for help. According to my interpretation of thermal image feed-thru holes are at temperature lower than nearby trace. I therefore conclude that they are being heated by the trace. Filling solder into the holes did not made any difference.
Schematics - only C-D block is published, driver block omitted. Inductors are not installed.
PCB - brown layer is top side, blue layer is bottom side. There is also equipotential layer ("ground plane") in the middle.
First thermal image shows untreated PCB with partial power applied. Second...
500 mil. Please note that specific trace which overheats is approximately in the middle of C-D chain and it bears only 6A
2OZ
Yes.
5 -10 cm. Actually it doesn't matter, because power dissipation is per length unit.
I will do it next Monday.
It is not possible in this specific design. I have...