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What to change to make speed keep up under load?

DMeie.2
Senior II

I'd like to make our application more aggressive so that it can keep its speed constant under different loads.
The speed regulator seems to be dialled in pretty good as it follows our setpoint perfectly fine.

However, when I load the motor, the current (Torque reference) barely goes up, and I can stall the motor by hand.
When checking the high frequency plot, Iq stays well below the configured limits.

What can I do to increase the performance in this regard?

6 REPLIES 6
hashiR
Associate III

i also need the same answer , could any one help regarding the same ?

 

While I cannot provide an official answer, this is what worked reasonably well for us.

It turned out that the automatic calculation of the speed regulator parameters (and probably the torque and flux ones as well, though we didn't touch those) by the Motor Pilot tool was way off, which resulted in way too low numbers for it.
After we increased those numbers significantly (in our case Pi from 2,6 recommended by the tool to 31, found by experimentation), the motor could reliably provide its rated power.

 

It would be interesting what affects the calculation of those parameters to know why they were set so wrong by the tool.

Could you please specify the parameters you adjusted in the Motor Control Workbench or in the code? I'm experiencing reduced motor speed underwater, but the motor is not reaching its maximum current limit. If you could share more details, it would help me attempt similar adjustments.

Did you modify parameters in the Motor Control Workbench, Motor Pilot, or directly in the code?

Could you share which specific parameters were adjusted?

Hey @hashiR 

according to what @DMeie.2  said,  the automatic calculation of the speed regulator parameters is just a good starting point and you must change these parameters in a way that fits best for your appliciation

same goes for the torque( flux) regulator parameters

you can change them in the code by refering to drive_parameters.h as shown below 

Screenshot 2024-10-28 152241.jpg

DMeie.2
Senior II

As for the specific value, that's very much dependent on your application and hardware.

What works well in my opinion is to experiment with those values in the Motor Pilot.
You can find them in the "Advanced Configuration". Values changed there apply live on the system so you can directly see how they affect it.

I tried tuning my motor by adjusting the torque and flux parameters (Ki and Kp values), but I didn’t see any noticeable changes.

Could you advise on the best way to adjust these values? Should I increase them gradually or make larger changes?

Also, could you explain how these torque and flux parameters impact motor torque?

My main issue is that the motor speed drops under load, but it only draws 0.2A, even though the motor’s maximum rated current is 1A