Micro Lebowski Controller - DIY 3kw

feel free to call me Andy....

I've split the schematic into three separate sheets and 3 separate PCB's so I can do some proper Net checking.

The good news is that there are no routing errors, it is as per the schematic. which makes it all the more important to get the schematic right. tomorrow I'll go through it again, looking for errors, most common errors are missed GND / +5V connections etc.. and wire-connections that look connected but are not.

Then I might bite the bullet and get some PCB's done up.

It's a slow process, I drive an hour each way to work, and enjoy playing with my 21 month old son in the afternoons, so free time is limited.

Thanks for showing interest. I'll update here as things develop.

Andy
 
Well I just spent 3 hours re-doing the 15v powersupply. It is now an LTC3638 like the 5v supply. Do both wool take up to 150v in. Emailed a Chinese PCB supplier I have used in the past. Awaiting a quote for 5 sets of boards.

I won't actually order them yet. Usually I get all the components first so I can verify all footprints. And mechanical considerations that aren't easy to model... Update when I know more
 
two quotes, both about $450 USD for 5 sets of boards. hmm.. I might look into a prototype panel, that's more than I was expecting. and i can add a few PCB's I've been sitting on for a while for the same cost. should be around $350 for 5 sets of controller boards, plus a few PCB's of other designs on a panel.

*** EDIT ***
PCBway.com $213USD shipped that's more like it.

Andy
 
i guess andy switched to 4 layer pcb which makes prices higher. i quoted this from oshpark.com.
i could just estimate the smaller pcb's size, but the two big one are 115x50, so i took 75x50 for the smaller one making it 152cm2 which equals 23,6in2 rounded to 24 in2. 4 layer pcb is $10 per in2 for a set of three. so 3 pcbs would be $240. as andy wants 5 pieces, he has to order 2 sets = $480 or $80/set. so much more expensive then oshpark.com.
to double check i quoted 5 boards, 4 layers, 300x50mm (for simplicity) with 2oz cu and quote is $164 shipping included or $33 per set from pcbway.com.
so i would choose pcbway.com :)
 
You got it right. Is 310 x 50mm for one PCB. Pcbway looks good.

I want to try one more place. They do 14.6x16.6in panels. Which I will fill with whatever I can fit. I have a couple of other PCBs I've been waiting to try.

Otherwise I just GO with pcbway to get the ball rolling.
 
4-layer.

I have found I can get much better component density with 4 layer and the cost hasn't been significantly different in the past. it also removes the issue of big long GND traces with the potential of inducing noise or having voltage drop around the GND path..

Andy
 
Decided to try pcbway. First I sent the PCB with only the top and bottom layers enabled. They picked up on this and emailed me saying it would be cheaper to do 3 individual PCBs rather than 1 larger panel. Anyways I did that but the total is now about $150 more. So I have resubmitted my first 3xpcb single panel. Cost sitting around $140 plus about $33 postage. Awaiting the file to be verified.

I'll notify here once they are actually ordered.
Andy
 
I just cut them with big wire cutters then clean the edge in a belt Sander. Then measure the internal planes for isolation. If you sand the edges length-wise or should be fine. If you sand across the PCB it could cause shorts. I've never really had a problem with it. But always measure the pcbs for shorts before stating soldering
 
I made slots between the boards so we can just cut the connecting tabs top and bottom with a cutter.
Anyways. Im jumping ahead a bit. I wanted to order components before the PCB so I can make sure everything fits. But the PCB is waiting on my shopping cart. Hope it's right...
Andy
 
ok well boards ordered. all up it came to $300 AUD delivered. I've got 5 sets coming. if anyone wants a set it's $60AUD plus postage - no warranties offered or implied. :twisted:

I'm going to contact Lebowski and get a couple of chips (2) and order the components to make up the CPU board as a minimum (x2) this way I can possibly sell off a brain board to someone who has their own driver / power stages and then I can afford to buy the rest of the components hahaha :mrgreen:

Andy
 
Nice design. How are the FET board and Cap/driver board connected? I read "copper bus bars" so i guess you solder it together? What about bolting them togeter by M3 or M4 screws? Guess this will intuce larger resistance?

Could you not use 6 or 9 smaller and more narrow caps instead of 3 larger ones? It feels like the current path could be shorter this way. to be honest i did not yet get how you wanna shape these copper bus bars, so they will have short connections to the legs of THT caps that lay on their sides :?

I dont see a lot of parts on the top side of the bottom PCB...and not many on the bottom layer of the middle one. Could the bottom and middle PCB be merged in the next iteration? Would make things easier to assemble and make the path from FETs to caps even shorter.

For the inrush limiter: I simply XT90s plugs that have precharge resistors built in...also works on the charger. The BMS i am working on will have an inrush limiter by in it. Common topology suggests to keep this seperated from the controller so i would stay with that at least for a while. Having the inrush control at the battery makes most sense in my eyes anyway, this way there is only one of these circuits in the whole system.
 
this cap could be mounted in stand up position... 18mm in dia but only 15mm in height
80V / 220 uF / 880mA ripple -> UPM1K221MHD6

I'm not sure if your really need Caps that accept such a lot of ripple current..but the more the better i guess. Sadly the more ripple the caps can stand, the less capacity they have for the same form factor. How much capacitance will be needed? is 2000uF enough?
 
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