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My thinking is that KP-ID 2000 is too big. Notice the first graph of Kp = 2000, Ki = 0, the error VERY QUICKLY goes to zero, but then zooms past and slowly goes to zero from the negative side. That overshoot of zero means Kp is too aggressive. My understanding is, when you double the voltage with PI loop tuning, that you have to cut Kp and Ki in half to get the same response time. And with a different, very large motor, maybe the current can change very fast due to very low resistance in the 3 stator coils? Try this:
Kp = 100 Ki = 0
Kp = 200 Ki = 0
Kp = 300 Ki = 0
...
And see if you get ZERO overshoot, meaning the error numbers don't zoom from + to - like this sample:
+0259
+0259
+0179
+0179
+0099
-0109
-0285
-0349
-0285
-0253
-0205
-0173
-0173
-0253
-0301
-0269
-0269
-0221
-0189
If you see it go from + to -, that's a sign that your Kp (or Ki or both) number is too big. We may have to increase the resolution of Kp and Ki in the software too. Your motor is a very interesting test case. I've never tried tuning the loop on such a big AC motor.
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