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DRV8301-69M-kit and new motor

Michael Mina1
Intellectual 480 points

Other Parts Discussed in Thread: LVSERVOMTR, 2MTR-DYNO, LAUNCHXL-F28027F, BOOSTXL-DRV8301

Hello.  I finally connected a new motor to my DRV8301-69M-KIT.  The motor is the Teknic motor that came part of the Dyno kit with two motors, motor P/N M-2310P-LN-04K.  The manufacturer gave me the following specs:

R=2.87 ohms phase to phase, and L=1.61 mH phase to phase.  He also gave Winding Resistance = 0.717 ohms, and Inductance is 0.402 mH.  The confusion is when I do motor ID, Lab 2a gives me the following: R=0.4423563 ohms, and Lsd=Lsq=0.0001962903 H= 0.1962903 H.  That's a big difference. Either way, all values don't agree.

So, (stupid question), when the manufacturer gives values phase to phase, how does that map to the numbers I get from the labs? phase-to-phase, line-to-line, etc...

Also, this motor is listed in the spreadsheet that we got from Chris couple of weeks ago, those numbers are also different.  My idea is to take these values and put them in a regular DC motor model for Simulink modelling that we can get from any textbook, and simulate this model.  These valuesshould be the stator resistance and inductance.

The values that the labs spit out, are they phase to phase, line to line, or what? Please help, it would make life easier to model these motors.

 Thank you.

  • 0
    TI__Guru** 119680 points

    You (or Teknic) is looking at wrong specs, you need to look at the P version.  There is a link the datasheet from the tool folder of LVSERVOMTR

     

    These are line-line and the Parameter ID feature of InstaSPIN-FOC will ID line-neutral, so half the values.

    0.72 ohm / 2 = 0.36 ohm and we usually ID on a given motor 0.36 - 0.44.  Rs is not the same motor to motor and will change with ambient temperature and due to current use.

    inductance of 0.4 mh / 2 = 200uH, which is pretty close to the 192uH you ID'd.

    inductance does change at frequency and loading. It's not so important that it's 100% correct, it just needs to be in the right area.

     

    so, you can model what you like....just realize that these values do change in system, especially Rs, which is why in a real world solution having our Rs Online feature is so critical.

     

  • 0 in reply to ChrisClearman
    Intellectual 480 points

    Thank you Chris, all the values from the labs agree.  Now for the other problem, one motor is vibrating very badly when I run it at 2.5 kRPM, anything above that, the motor is ready to fly off the table.  I noticed that this motor has a high frequency pitch at any speed, personally I think the motor is defective, Should I buy another motor from TI? This was part of the 2MTR-Dyno set.  The second motor starts to have little vibration at 4.0 kRPM and above.  also, you told me couple of months to run lab5a for the 2MTR-DYNO, are there better descriptions or directions as to how to run this lab with these 2 motors.

    When i run lab05c for inertia identification, I set the velocityMaxSpeed to 6 =kRPM (that's what the motor is), i get the 2004 error, then i lowered it all the way down to 2kRPM, iget 2004 error, ofcourse the motor is vibrating badly running lab05c.  Chris, I think I needd to order another motor.  What do you think?

    I like to demonstrate this to some people at work.  Thanks again Chris.

  • 0 in reply to Michael Mina1
    TI__Guru** 119680 points

    Michael Mina1 said:
    I noticed that this motor has a high frequency pitch at any speed, personally I think the motor is defective

    Hmmm. It certainly sounds suspect.  If you take the exact same software (with same gains, etc) that runs the other good motor the bad motor always has this issue?  if so I would certainly suspect damage.

    Michael Mina1 said:
    Should I buy another motor from TI?

    I would contact www.teknic.com and see if you can return the motor for inspection / replacement?  I would think they would.  If you need another one quickly you can order LVSERVOMTR which just includes the one motor (and this also comes with the wiring harness which is nice to have as it breaks out all connections to bare wires).

    Michael Mina1 said:
    also, you told me couple of months to run lab5a for the 2MTR-DYNO, are there better descriptions or directions as to how to run this lab with these 2 motors.

    Do you mean for the DYNO side?  What's even better is to use a sensored lab with encoder feedback. This way you don't have issues at zero and low speed.  You can use instaspin_motion proj_lab12 for encoder based speed control.  You can also adapt this lab (by viewing the SW in 5a) to turn off the SpinTAC speed controller and provide an IqRef_A torque reference (but still use the encoder for angle feedback).  This will most closely emulate a dynometer where you set a specific torque load to your motor under test.

    We are still working on the inverters and software to accompany the 2MTR-DYNO kit.  We have a single board with 2 inverters and a controlCARD slot (so both motors are run off a single F28069M) but we decided instead (due to popularity) to do the hardware using BOOSTXL-DRV8301 inverters.  So we have a new LaunchPad with 69M that will allow you to plug in two BoosterPacks.  Or, you could have one controller for the DYNO and one for the motor under test (either the new 69M or the existing LAUNCHXL-F28027F).

    We are working on production of the new 69M LaunchPad and will release in the fall.

    Michael Mina1 said:
    When i run lab05c for inertia identification, I set the velocityMaxSpeed to 6 =kRPM (that's what the motor is), i get the 2004 error, then i lowered it all the way down to 2kRPM, iget 2004 error, ofcourse the motor is vibrating badly running lab05c. 

    is this only with the "bad" motor?  what about with the good motor?

    I know the Teknic motor won't reach 6 krpm with only 24V. It's rated at about 60V I believe to reach those speeds.