Cheap FOCer 2 (Open-source, Low-cost, VESC 6 based ESC) (v0.9 release! Beta testing still ongoing)

[SRFirefox]

Bought my first batch and freshly assembled these FOCers. With some moving and life, a bunch of stuff has gone missing, but I found some old Leopard boating inrunners I pulled out of some junked boats a while ago. My first thought was that they're too low inductance and I shouldn't bother, but hey, I'll blow one up for the team.

Turns out, I needn't have worried. Parameter detection went well and just worked the first time. While I doubt they're perfect, I'm not back to work with an LCR bridge for a little bit yet, so it'll have to do for now. 10.8mOhm, 1.39uH motor. I found an old 7S lipo and ran it out of the balance tap on different voltages and up to 100k eRPM. It got hilariously warm for an unloaded motor (still not uncomfortable to touch), but overall spun up and down as expected for a first test. I definitely give the CF2 my seal of approval!

 

[shaman]

@SRFirefox nice test and thanks for sharing! 1.39uH is a challenge. Out of curiosity, have you tried increasing the switching frequency for FOC to see if it reduces the heating? You could try bumping it up to 30 or 40kHz.

 

[SRFirefox]

I tried it at 50kHz, but it didn't appear to affect motor heating at all. I suspect that the resistance and inductance measurements are probably not accurate, but I don't have the test equipment to measure these outside of the VESC software. One of these days I'll get a DE-5000 LCR meter, but today is not that day.

 

[amberwolf]

If you're close enough to Phoenix, AZ, you can bring the motor over and use mine.

 

[SRFirefox]

Thanks for the offer, Amberwolf, but unfortunately the meter would be cheaper than a trip to meet you. Much appreciated!

 

[SRFirefox]

So I've had a couple DRVs fail (not unexpected with my messing around), but I seem to be having the issue that when I reach 40ish amps phase @50% duty that my DRVs throw faults. As in all the faults. My test motor is a mid-monster that I'm running as a self-contained dyno to test the Cheap FOCers to see how their current/power performance pans out.

I've tried both FW 5.x and 4.2 from the CF2 repository and get the same result on both. The biggest difference seems to be the measured inductance of the motor being 5-15% higher on FW4.2. Have you seen these problems? I presumed it wasn't my battery (a 10s4p pack of INR18650-29Es) since I'm driving one FOCer and regening on the other. I've managed to get a single FOCer up to about 60A phase by shorting the second set of phase leads together, but even that seems hit or miss. Sometimes I see these all-faults even as low as 15A.

Any insight you might have would be greatly appreciated.