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Old 05-26-2015, 02:08 PM   #1858 (permalink)
thingstodo
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Quote:
Originally Posted by MPaulHolmes View Post
OK this is good! There are a few differences between your test and the instructables test. First, you are using a LEM Hass 300-s, and are commanding 20 amps. I was commanding 5 amps I think, so the response instructables response would be a lot faster, since the current wouldn't take as long to get to 5 and it would to get to 20.
I follow so far. I guess I didn't know the parameters of the instructable test.

Quote:
Also, if you are running it at 36v, maybe the resistance of the phases are high enough so that 20 amps is barely achieveable using the 36v battery pack? What is the HP rating of your motor?
It's a 5 HP, 230V 3 phase. Full load amps is 17.5 (internet lookup but it should be close) ... so I will boost the voltage. I have a crappy little 48V pack that I can put in series to get 84V.

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I did a test on a 6.6kW (I think) motor. My guess is a higher power motor would have lower resistances, and faster convergence times.
Lower resistance and inductance - check. Obvious now that you pointed it out!

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Also, you haven't tried increasing ki-id yet.
I was looking for the drop to 0 quickly, so I did not progress to kp-id

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kp-id just gets you close to converging, and ki-id really drives it to zero fast. Here's what I would do next: Start at kp-id = 2000, and gradually increase ki-id (not kp-id). Start at maybe 2, and go up by 2 at a time.
OK - I can do that.

Quote:
Also, the oscillations you are seeing aren't really oscillations, but just noise (your noise level is perfectly acceptable). Oscillations will be clearly defined damped sine waves with a much lower frequency than the jaggedy spikes you are seeing.
OK. I guess I should capture some data to document what is acceptable and what is weird.

Last edited by thingstodo; 05-26-2015 at 02:49 PM.. Reason: correct 64V to 84V
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MPaulHolmes (05-26-2015)