TMS320F28069: InstaSPIN: current feedback for torque control regulation

j.seydoux

Hello,

We are working on an industrial robot that will embed C2000 motor controllers with InstaSPIN. Since we are new to the InstaSPIN solution, we would need your help to clarify some things.

In our system, we use encoders so we do not use the FAST Estimator.

My question is: what current feedback coming from the InstaSPIN library can we give to a higher-level algorithm to handle torque regulation?

In other words, on which feedback from the FOC can we calculate the new Iq reference for torque control?

Thank you in advance for your help.

Best regards

over 5 years ago

0 Yanming Luo over 5 years ago

TI__Guru** 116850 points

You might refer to the example solutions in motorControl SDK since you are using an encoder for position sensing.

MotorControl software development kit (SDK) for C2000™ MCUs

http://www.ti.com/tool/C2000WARE-MOTORCONTROL-SDK

Generally, all FOC solutions need two/three-phase currents of the motor to control the torque current (Iq) by transforming and the current controller.

Two or three motor phase currents are measured. These measurements feed the Clarke transformation module. The outputs are isα and isβ and are the inputs of the Park transformation, which transform them to currents (isd and isq) in d and q rotating reference frame. The isd and isq components are compared to the references isdref(the flux reference) and isqref (the torque reference) to control the torque or speed of the motor by current controllers.

You might take a look at the following link, and find some motor control knowledge on the reference links.

https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/855709?tisearch=e2e-sitesearch&keymatch=faq%3Atrue

0 j.seydoux over 5 years ago in reply to Yanming Luo

Intellectual 740 points

Hello,

Thank you for your answer.

So if I summarize, we should base the new torque reference on the the Iq current read using the API function CTRL_getIq_in_pu.

Here would be our Iq current reading in ampers:

iQ_A = _IQmpy(CTRL_getIq_in_pu(handle), _IQ(USER_IQ_FULL_SCALE_CURRENT_A));

Could you please confirm this?

Regards,

0 j.seydoux over 5 years ago in reply to j.seydoux

Intellectual 740 points

Hello Yanming,

Any feedback regarding my answer above?

Thank you.

Regards

0 Yanming Luo over 5 years ago in reply to j.seydoux

TI__Guru** 116850 points

Right, you can get the real q-axis current (Iq) by using CTRL_getIq_in_pu(), and d-axis current (Id) by using CTRL_getId_in_pu(). Both values are PU format and are calculated by using Clarke and Park transform functions as I mentioned above.

Yes, you need to use the PU values multiply the scale value to get the real SI value as you mentioned above.

A more detailed description of these functions can be found in InstaSPIN user's guide (http://www.ti.com/lit/ug/spruhj1h/spruhj1h.pdf ) as well.

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TMS320F28069: InstaSPIN: current feedback for torque control regulation