Vissie wrote: ↑
Tue, 11 Sep 2018, 19:27
This one had ghekko's inside that shorted the bus.
Wow. I bet the critter involved had a bad day too
The battery side fets and the 4 igbts of the inverter full bridge and the buck igbt were blown. It also burned a hole in the main board. Also a few drive resistors were gone.
Well I managed to scope the signal like Coulomb described and the signal looks fine. I get the gate signal on the bat side fets and on the dc dc igbt's
Ok, that's good.
I do not get a pulse for the igbts on the inverter full bridge Igbts but it seems like its driven from a small ic or maybe the control board
Yes, the main inverter IGBTs are driven by ePWM1 and ePWM2 (both A and B outputs, so 4 signals total) of the microcontroller. So that's from the control (daughter) board, probably buffered on either the control board or the main board, or possibly even both.
So I am bit scared to switch it on without knowing if they get signal. I think after building all the faulty parts back I should only connect the current limited dc supply on the battery terminals and see what happens
That's wise. Unfortunately, I don't think we've figured out how to do that as yet.
The answer would seem to be a sort of dummy daughter board, which might be little more than a piece of Veroboard with appropriate pins (maybe less than a dozen); you'd want to make sure that no gate driver inputs are left floating. Also ensure that the bus soft start circuit is disabled. It would be nice if it's difficult to plug in such that the pins are one hole away from where they should be.
The board might have a pair of 555 ICs, and maybe a switch, so you can pulse the upper IGBTs and lower IGBTs separately or together. Of course, have generous dead time built into the circuit, so the upper and lower transistors of a pair never turn on together. This would all be run with about 12 VDC current limited to 0.5A or so on the DC bus.
If you work it out, please publish the schematic here.
Please can some one tell me how to post photos. I got it right the first time but not again
Just drag an image into the edit pane. Or, since you've done it before, the main trick to remember is that the needed attachment tab is often off the page, and you need to use scroll bars to get to it.
However, we have had some users claim that sometimes the attachment tab simply refuses to appear. It's never happened to me, but I haven't been posting many images or other attachments on this forum lately. Our web master, Rob, is aware of this issue, but last I know (a week or so ago) he was at a conference and had little spare time for web administration. It's also rather baffling. It's possible that you can drop an image into the edit pane even if the attachments tab isn't visible.
There is also my New Forum Tips
post. Scroll down to the "How to post an image" section.
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.