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Hub motor FOC detection.

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Roger Wolff
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VESC FreeVESC Original
Joined: 2017-05-24 12:27
Posts: 202
Hub motor FOC detection.

Hi, 

I have a new motor for my bike. (Something went wrong with the previous motor/controller. Both ended up fried.). 

 

Now this is a hub motor, so there is a bike wheel attached. Sure I could remove the wheel, but I'm pretty sure I can't put that one back again straight. So... I'll have to do the detections with the wheel on it. 

The RL measurement is fine. 

Now the standard lambda measurement tries to spin the motor way too quickly. With the wheel attached not an option. 

After a few tries with higher current and lower RPM and pushing the wheel while vesc is trying to spin it up I finally got a detection. That did not run nicely. So I increased the measured value by 5 (mWb) and... the motor ran better. So I increased it again and again. So now I'm at 5 times the measured value or something like that. So the measurement was totally off. 

 

Anyway. I don't know where the calculated values depend on, so when the lambda measurement fails, I cannot do those calculations. When I guess a lambda I cannot enter it in the measurement tab to do the calculations. Benjamin once told me how to do the lambda calculation when I know the KV.  Not sure if I can find that again. 

 

My suggestion would be that once the wheel is spinning (any way I like) I can hit a "get lambda now!" button somewhere so that the lambda measurement is taken at that point in time. 

 

Another suggestion would be to change the "try to spin it in open loop BLDC mode"  to something like: FOC_OPENLOOP with configurable current and ramp-speed. Two parameters (now three) and I'd guess you can get any motor spinning that way....