Guru
Joined: 17/10/2017
Location: BelgiumPosts: 471
| Posted: 09:15pm 18 Apr 2021 |
You can call it Chinese, but it's a technique Mastervolt,Victron and Studer used in their (some older) designs, just to mention some brands. In my opinion there's is nothing wrong with that if you know the pitfalls like you said. You say temperature could cause issues, yes, capacitors are degrading faster with higher temperatures. But with poida's software you can easily adjust the parameters to start the ventilation as soon as you want and due to the heatsinks the wind is guided perfectly around the capacitors. Only 1 fan is needed to cool down the components.
I agree with you that mounting the fets under the PCB could have more advantages. The cooling down of the fets could be made more efficient and even passive to achieve lower temperatures or pushing the fets harder. But I find it's a challenge to design the mechanics arround.
It's on my list to draw an inverter PCB with fets under the PCB. In fact I do design my PCB's with fets 99% like that. Including 3ph and half bridge pcb's, but still not 100% satisfied about the results, I keep adding adjustments and keep thinking it's not good enough. Today I was looking at a 3ph design and I was telling to myself, why didn't I draw the +- and AC connections the other way around that would have been more logical.... One's satisfied I will post it, I plan my next build next year, I really need a spare inverter for when things go wrong. I need to look up your builds for inspiration.
Btw, I know solarMike, Wiseguy and mackoffgrid to mention some forum members, have posted designs with mosfets mounted under the pcb.
Edited 2021-04-19 07:22 by nickskethisniks