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TMS320F28388D: Trouble with level 3 of FCL code

david goodin
Intellectual 400 points
Part Number: TMS320F28388D


Greetings, 

Am running the FCL project using the 28388 card plugged in to the Industrial drive experimenters board.

I have a 3phase BLDC motor with incremental encoder. I am able to run the project at level 2. The motor spins when the VqTesting level is set to 0.2 or above. 0.2 give the smoothest motion. The motor runs open loop fine and the speedRef value allows chaning the RPM.

When I switch to level 3 , the motor does not spin and only vibrates.

Not sure what I am missing here, any poke in the right direction will be appreciated.

David

  • 0
    TI__Mastermind 27240 points

    I suspect the sense of rotation of motor and that of the position sensor feedback are opposite. Try to swap two of the three wires feeding the motor.

    All this info is given the guide, pls review.

  • 0 in reply to Ramesh Ramamoorthy
    Intellectual 400 points

    Thanks Ramesh,

    I am measuring the D/A ramp outputs for estimated and measured rotor position and the ramps are correct. So, I do not think that is it. However, just for grins, I swapped the A/B lines of the encoder to reverse that and...same result. Motor just jitters a bit with a sound of "frying eggs".

    Something strange indeed.

    David

  • 0 in reply to david goodin
    TI__Mastermind 27240 points

    Hmm, do you see an initial alignment of the rotor shaft. Also did you try to assist the rotation by trying to help it spin from zero speed if you find it safe to do so?

  • 0 in reply to Ramesh Ramamoorthy
    Intellectual 400 points

    There is no alignment of the rotor shaft. The motor does not attempt to actually spin at all. The state machine is looking for the index. If I rotate the motor by hand, past the index, the state machine will advance to where it belieives the rotor is aligned.

    There is what feels like detent torque on the motor. When gripping the motor shaft, one can feel it "trembling".

    I have run the "non FCL" project on the development board and the motor behaves as expected. The motor aligns and spins with a good amount of torque. It also does the position mode as expected moving from point to point. I followed the process on that project as well advancing the "build level" one at a time verifying each step.

    I am attempting to do the same with the FCL. Level 2 spins the motor (open loop) and I can see the D/A outputs giving the "ramp" signal for rotor position as expected.

    Kind of stuck on level 3 on FCL.

    As a reminder, I am running this on the "big blue" board.

    Regards,

    David

    David

  • 0 in reply to Ramesh Ramamoorthy
    Intellectual 400 points

    Hi Ramesh,

    So, after looking again, realized that the motor parameters were not set up correctly. After correcting that, the motor does the alignment and spins.  

    Is there any detailed documentation about the variables used and their meaning in the FCL algo?

    David

  • 0 in reply to david goodin
    TI__Mastermind 27240 points

    The variable names are self explantory. All that you find in the user guide is what we have. Glad it works. 

    Reg variable names, i am sure you can figure it out.

    Am closing the thread, since the issue is resolved.