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Lab04

Sam Hawker
Intellectual 850 points

In Lab04 if I enter a reasonable value for IqRef_A then my motor doesn't spin. If I enter a large value then it immediately spins up to voltage limited speed. In both cases gMotorVars.Iq_A is reported as 0.0. For some reason Kp_Idq and Ki_Idq are also both zero. Have I done something stupid or is it just that I need to progress to the next lab and tune Kp and Ki?

  • 0
    TI__Guru** 119680 points

    Sam Hawker said:
    For some reason Kp_Idq and Ki_Idq are also both zero.

    you can update these in 05a

    Sam Hawker said:
    In both cases gMotorVars.Iq_A is reported as 0.0.

    gMotorVars.Iq_A is not "pulled" in lab 04. You have to go to 09 or 10 to pull these values (or copy how we did this into your own lab).

    Sam Hawker said:
    In Lab04 if I enter a reasonable value for IqRef_A then my motor doesn't spin. If I enter a large value then it immediately spins up to voltage limited speed

    What is reasonable.

    If you slowly increase in 0.1 A increments it will eventually start-up. Having ForceAngle active will help it start-up better.

    If your motor has low cogging torque this value will be quite low, with higher cogging torque it could be up to nearly 1/2 the rated current.

  • 0 in reply to ChrisClearman
    Intellectual 850 points

    Thanks Chris. Sorry - I probably should have been able to figure that out.


    I've finally gotten around to trying out the Launchpad and BoosterPack and I'm quite impressed. I'm now using a very small in-runner motor (0.11ohm, 15uH, 3000rpm/V) and with no load it goes from +35k rpm to -35k rpm in about 1s. Speed estimation is reasonable down to about 100rpm. Still looking forward to the initial position detection algorithms though.

  • 0 in reply to Sam Hawker
    TI__Guru** 119680 points

    glad you are seeing some success.

    regarding IPD, it's coming very soon.  I'm not completely optimistic how well it will work on these little hobby motors...although we are running it on low Ls / low flux power tool motors very successfully.

    we'll have to see....IPD isn't really needed for a propeller type of load, but these types of motors are being used in traction applications where the load can be quite high and there IPD is required.