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D vs omega control

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Last seen: 3 years 2 months ago
Joined: 2021-03-08 19:53
Posts: 6
D vs omega control

Apologies if this is a basic question, but I can't seem to find the answer anywhere.

I've got an FOC application. Under the FOC menu I have 'Encoder' chosen as 'Sensor Mode', but then under the Encoder tab the 'Sensorless ERPM' is set to 4000, which is lower than my min, so I believe that means it's running sensorless all the time?

My question is regarding the D and ω fields. I've tried using each of those for controlling my motor, and I've noticed some differences between them. Specifically:

  • at min or close to min ERPM values, the motor current is quite a bit higher when I use the ω field vs the D field (average of 5A with ω, 1.3A with D, to be specific).
  • when changing speed (I noted this when changing from stopped, but it may happen for every speed change), if I use the ω control it overshoots the desired ERPM and then settles to it after a second or two, whereas if I use the D control it hits the desired ERPM pretty instantaneously

There may be more differences but these are the couple I noted so far, which leads me to believe there must be some difference with the applied control between these two fields. What is it?