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Old 09-18-2015, 10:03 AM   #2046 (permalink)
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Originally Posted by MPaulHolmes View Post
I would err on the side of the rotor time constant of like 13 even though it isn't the highest RPM. The graph goes up nice and smoothly, then the rpms start to get more erratic.
From holding the motor (literally, both hands on the motor holding it down on the base) I would suggest that when regen is required to slow down the motor, prior to the next set of values being tested, perhaps slow down the motor a bit more. I don't know what speed things are going, but I got an overspeed fault at max-rpm 6000 ... my testing is done with max-rpm 10000. That's getting up there in the torque curve. We may get better results if the regen drops the motor speed for the start of the test set down closer to 1000 rpm?

I think that's because the voltage disk is clamping more severely, which means the PI loop is having a hard time commanding the Id,Iq for those larger rotor time constant candidates.
That may also be true. The deceleration is more aggressive than the acceleration right now. There is enough torque commanded to lift the 200 lb motor half an inch off the base during regen (which is why I was putting my weight on it to keep my encoder alignment close). The acceleration appears to go hard and then cuts out - not sure if it is current clamp, or you run out of voltage to apply, or your slope on the speed gets too high ... something is limiting the larger rotor time constants.

Also, you can do some voltage and current captures (I'll send that today), and find the stator inductance curve, so we can get sensorless moving!
I'll have an hour or two this evening before we head out to the cabin tonight. If there is anything specific you want me to test (specific currents, or every 10 amps, etc) let me know and I'll get to what I can.

I'm still promising video posted this weekend.
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