Quote:
Originally Posted by MazdaMatt
Very nicely done, Paul. That mill is really helping you turn out nice work 
Do you have much experience soldering?
Have you considered adding vias to the board?
Is it truely necessary to use SO MUCH copper? What other options would there be for so much current and heat handling? I'm just thinking from a mass-production economics p.o.v.
There is no question, you'll want to use that thermal paste for longevity/safety.
Looking forward to seeing it in action |
Hey MazdaMatt! I have very little experience soldering. I just know the basics. Is a via a path for current to flow from one side to the other of a pcb? That's part of the function of the brass bolts. I think the copper heat spreader is not necessary. Aluminum would probably work just fine. The copper bus bars could be more narrow, and then widen on the outside of the controller to allow for bolting lugs to them.
One option for heat handling would be liquid cooling which really isn't that complicated. Just drill a U shape (with a little trickiness) in an aluminum heat spreader, and run water through it with a small pump. Make sure there's a little water reservoir outside the controller. That would eliminate the cost of the external heat sink too.
Another heat handling option is to eliminate the freewheel diodes, and use mosfets. The mosfet acts like a diode. Current can always flow from source to drain, but not drain to source. So, when you want one to conduct from source to drain, it goes through the "body diode" momentarily until you turn it on. Then there is almost no heat loss (whereas the freewheel diode has lots of loss here). When you want it to start blocking current that's coming the other way, just shut it off (bring gate back to 0v). It's called Synchronous Rectification. There's an AVR that has special features to make SR easier. It only comes in surface mount format, though. I ordered some solder paste. I need to learn how to mount surface components.