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Anyone built a BLDC controller?

Posted: Wed, 19 Jun 2013, 03:18
by Canberra32
Hey guys n gals.

I'm in the middle of building a electric gokart for the kids and rather than use a run of the mill controller I was wondering if anyone on here has designed one ?
The motor is a mars ME907 brushless 5-10kw 48volt

I mean its easy enough to just buy one but easy is not my style lol

Anyone built a BLDC controller?

Posted: Wed, 03 Jul 2013, 02:59
by aegidius
I have done this many years ago. It was based on an MC33035 BLDC controller chip and some 100A mosfets. The motor was a car alternator with opto pickups for the sensors. It worked up to 36V but had a few limitations - getting the high side mosfets to turn off quickly was a pain as the voltage increased. Generally I'd say it's easy in theory but they are very tricky to get reliable and bug-free, especially as power and voltage increase.

Maybe try a Kelly BLDC controller, that's one name I can think of - I don't know the market very well any more.

Anyone built a BLDC controller?

Posted: Wed, 03 Jul 2013, 04:15
by Adverse Effects

Anyone built a BLDC controller?

Posted: Wed, 03 Jul 2013, 13:43
by Canberra32
Apparently the hobby ones have a soft start and not so good for a drive situation as a fly situation

Anyone built a BLDC controller?

Posted: Thu, 04 Jul 2013, 05:23
by Adverse Effects
you can turn off the soft start

Anyone built a BLDC controller?

Posted: Thu, 04 Jul 2013, 20:57
by Richo
They are no good.
They still need the sensor inputs for good eV use.

Flying - the torque is proportional to RPM so low torque on startup.
RC cars are very light so soft start is fine.
Go karts are heavier and have high torque start.
Same problem was found for ebikes using RC parts.
It'd work poorly for a while until it blows.

Anyone built a BLDC controller?

Posted: Fri, 05 Jul 2013, 13:29
by Canberra32
Yeah there is a MIT professors blog I like that warns people about them.

But was more after if someone had a design for one then I could build it.
Going for the Emmit Brown look :) I know it won't work out cheaper than just buying one but more interested in the fun factor :)