With the release of vesc tool and 3.28 I decided to try FOC. setup was a bit buggy as i got failed detections and the “r is 0” bug, but i was eventually able to get everything setup. I copied my current limits from bldc on 2.18, but had a couple issues in my first ride. Here’s my setup…
10s4p Samsung 25R
Each VESC (dual Ollin 4.12 setup):
motor max: 70
motor min: -70
battery max: 40
battery min: -8
FOC sensored
The problem:
The brakes are noticeably weaker than bldc while startup is about the same strength. There is a slight delay when accelerating and braking as well but i chalked this up to FOC limitations. I’ve already decreased ramp up time to .1s
When i blast the throttle from standstill (unloaded) or quickly speed up going uphill (or I assume anytime I’m drawing a lot of current), The Vescs cutout and the wheels stop spinning until i let go and throttle again. The behavior is as if I’m getting over current, which i may very well be, but not sure why this happens in FOC and not BLDC. Haven’t checked error codes yet, but I’m assuming over current, will update later.
The board otherwise works fine with smooth startup and no issues running at 50k erpm. Any input is appreciated!
FOC is sensitive to sudden acceleration, mine cuts out at 0-100% throttle momentarily, It some times lose pole detection, also momentary, but sensored shouldn’t do that
but if its over current u can increase absolute max up to 150a safely, though I only goes 140a.
accelerating ramping u can just kill it with 0s, but I saw people complaining even after that. I haven’t try so…
Sensored shouldn’t have much to do with it given that it moves over to sensorless at about 3mph (7000eRPM). If I am getting over current faults I’ll check tonight to see how much current I’m drawing.
If the full throttle cutouts are something i “just have to live with” then I’ll probably switch back to BLDC.
I will miss the quietness and battery efficency though, I ended up with like 4-5% more battery at the end of my 3.7 mile ride.
Strangely my case was opposite to you XD
I had over current in BLDC in braking and Switched to FOC,
Efficiency only noticeable over 10miles I think, I get 3 miles more over BLDC
Honestly I’ve encountered that on every vesc, about 6 diff ones now. I can’t pin down the problem. I replaced everything from the fets, the shunts and caps, resistors and the issue always shows up again
Fault : FAULT_CODE_ABS_OVER_CURRENT
Current : 280.5
Current filtered : 125.2
Voltage : 28.19
Duty : 0.705
RPM : 13659.7
Tacho : 365
Cycles running : 1176
TIM duty : 5918
TIM val samp : 2
TIM current samp : 4200
TIM top : 8400
Comm step : 0
Temperature : 38.06
VESC 2
Fault : FAULT_CODE_ABS_OVER_CURRENT
Current : 329.6
Current filtered : 128.3
Voltage : 28.04
Duty : 0.932
RPM : 13752.8
Tacho : 368
Cycles running : 1186
TIM duty : 7830
TIM val samp : 2
TIM current samp : 4200
TIM top : 8400
Comm step : 0
Temperature : 33.40
:0
This is full throttle on the bench from dead stop with the wheels/belt attached
If I am, any ideas what might be causing it?
