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MOTORWARE: Question about inductance of motorware.

Daniel Mueller
Intellectual 890 points
Part Number: MOTORWARE
Other Parts Discussed in Thread: DRV8301

Hello Ti,

I have a question about Instaspin-FOC from Motorware, Lab11x.

Does this function “softwareUpdate1p6“ needs to be called all the time? I saw a post where Yanming said, it is needed for running, but why?

I read somewhere this function is to load the user.h inductance values in right IQ format to the estimator. Does the estimator recalculate the inductance when it is running? If not, can I just call it once on startup?

I want to add decoupling and save some bandwidth, therefore I’m asking.

What inducrtance values can I use for decoupling?

Best regards,
Daniel


  • +1
    TI__Guru** 112250 points

    If you don't want to change the inductance online, yes, you just need to call this function once as you mentioned.

    Daniel Mueller said:
    What inducrtance values can I use for decoupling?

    The real inductance (Ld and Lq) you used in the lab.

  • 0 in reply to Yanming Luo
    Intellectual 890 points

    Good evening Yanming,

    thank you for clarification.

    I assume online adaption of the inductance is not the usual case? I never saw a motor datasheet where there was a plot of an inductance in it.

    When does it matter to update the inductance online? Is the inductance current dependent, I think I read that somewhere?

     

    Axis decoupling works great Blush


     Just another question, with low currents (my board is able to drive 80A), I see some oscillations on the iq and id feedback, also on the regulator outputs vd and vq, below is a picture of it. Is this normal, where do they come from? I have some assumptions but I’m not sure if this is right. Some words of an expert would be nice Blush

     

     

    Best regards,
    Daniel

  • 0 in reply to Daniel Mueller
    Intellectual 890 points

    I forgot to mention, I use a F28069 and lab11 based software from motorware. I checked the code and implemention a lot of times(debug an matlab simulations), should be everthing ok. The hardware should be also ok, same behaviour with the DRV8301 kit. I also tuned the pi regulators.

  • 0 in reply to Daniel Mueller
    TI__Guru** 112250 points

    Ok. You just need to call the function once that is the same for lab11.

  • 0 in reply to Yanming Luo
    Intellectual 890 points

    Hello Yanming,

    no, I meant not the softwareUpdate1p6, everything is clear to me about this case. Also when I have to update ld and lq online.


    I just wanted to know where the oscillations come from, therefore I mentioned what hardware and software I use. The oscillation peak does not increase with the current, bit different waveform, but peak is still the same.  I don’t have any problems, would be just nice to know. Your opinion would be really nice.

    Please answer this question, just a few words.

    Btw. We are driving a small electric vehicle (5kW) based on Instaspin and it works really well.

     

    Best regards,
    Daniel

  • +1 in reply to Daniel Mueller
    TI__Guru** 112250 points

    That could be from the current sensing signals and current PI controller. You can reduce these oscillations by improving the current and voltage sensing signals and tuning the current regulator, but you can not remove this oscillation.

  • 0 in reply to Yanming Luo
    Intellectual 890 points

    Thank you Yanming!