Paul & Sabrina's cheap DIY 144v motor controller - Page 431 - Fuel Economy, Hypermiling, EcoModding News and Forum

MPaulHolmes · 02-05-2011, 03:09 AM

Hi Bill! I need to come up with a bill (haha) of materials. I've been getting my mosfets from Allied too. WAY cheaper than digikey. Let me see if I can find the diodes...
Digi-Key - APT60S20B2CTG-ND (Manufacturer - APT60S20B2CTG)

The capacitors are the same as the 1000uF 200v Panasonic TS-ED ones that I've been using. Anything from this list would be fine for the polypropylene capacitors:
dc link epcos

10 of them. You could go way beefcake with the 12uF ones, or smaller with the 2.2uF ones. The bigger, the higher the ripple current rating and lower the ESR, but I don't know if much is really necessary. Overkill doesn't hurt. It's just a question of how much you want to spend. anywhere from around $22 up to $75 on those.

for bus bars, 3/8" x 3/4" x 13" for B+ and B-.
3/8" x 3/4" x 14.8" for M-. I just have to see how that surface mount current sensor board works out. Some sort of heat sink base plate would probably be good. About 14" x 7" finned aluminum heatsink.

billhac · 02-05-2011, 03:28 AM

im ready when you are once you get it worked out just send me an invoice, in the mean time ill be waiting for the 500 amp power board, so i can get started on it, iv got everything else comming. btw I sent my revolt controller to an aluminum fab shop here to have a nice cover made and see if it can be incorperated as a heat sink when bolted to the base plate, cant wait to get it back to look at it. the cover I made for it really sucked and I was tired of looking at it.

flores · 02-05-2011, 03:35 AM

Paul, this is a DC controller right?

I take one 1000A.. i've got a car to test it in.. so bring it on.

billhac · 02-05-2011, 03:40 AM

better start getting them ready, i got a feeling there will be some interested people out there.

MPaulHolmes · 02-05-2011, 04:18 AM

Well, 1000amp is with a 50% derating on the parts. hahaha. Here's my problem:

The dang blasted friggen stupid setup fee for the stupid idiotic boards and shipping! 2 driver boards, 2 power boards, and 2 control boards.

The setup fees for the power board:

For the driver board:

For control board:

But check out how cheap they get in bulk!!! Like $0.50 each.

Well, I have $55 because Bill ordered a power board from me, that I still haven't milled yet, but don't tell him that. I'm doing that this weekend.

I can build and solder and test the controllers at lower power, since I don't have a motor that can test it at 1000 amps, if you guys want to pay for parts, and share the cost of the boards' first order with me? I have $55 to donate to it.

What happens if by some bad miracle something just blows up in testing? I won't have the money to reimburse you guys.

MPaulHolmes · 02-05-2011, 04:22 AM

Speaking of Chinese control boards. I lost my dog yesterday, that's because the Chinese emperor guy was visiting my house. HU LET THE DOG OUT HU HU HU HU!

MPaulHolmes · 02-05-2011, 04:36 AM

OK, I'm going to post the schematics and pictures of everything, and if people can look at it and make fun of it, you all might notice something that I'm not noticing. Like problems with layout, or just a plain old mistake. Then if it seems Ok, and I check it over again when it's not 12:30 at night, then I think it will be ready to send in.

MPaulHolmes · 02-05-2011, 05:23 AM

Does anyone want to see why I post things at 2 am?! I just took this picture 1 minute ago:

OK. Here's some stuff to check... My only concern here is in between the diodes, but I'm going to add some serious copper between the diodes. I could just have the diodes be surface mounted like they are now, but that increases the stray inductance and magnitude of spikes:

Also, having it be thru-hole diodes could increase the noise the control board sees? But I don't think that will be much of a problem. Stupid trade-offs. Makes me mad.

The 3/8"x3/4" B+ and B- bus bars are mounted so that the 3/8" side makes contact with the board. That cut a good chunk out of the loop.

Another concern I have: The surface mount current sensor has a less than 8uS response time, whereas the LEM had a less than 3uS response time. With a nicely tuned PI loop, the current should be kept under control, so I'm not too worried, but just something to think about.

I just checked the schematic, and I am very very very sure there aren't mistakes. hahaha.

Here's the optocoupler part:

Here's the automatic precharge part. The relay just wastes about 30mA while you are driving, which saved the use of a pin on the microcontroller, and a couple dollars in components, and routing where there wasn't much room. Is it a problem to use a 1N4148 diode for the relatively puny coil to protect against inductive kick when the coil gets turned off? I read about it today and the consensus on the web seemed to be that it's fine for a 30mA 12v coil.

Here's the control board layout. The scale is 7.470" x 2.6". Relay, and high voltage stuff on the right side. There are a few extra holes so as to make the board compatible with Mr. Bighs IGBT board:

Here's the control ground plane in white. As unbroken as I could make it, since I think that helps with noise immunity.