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LAUNCHXL-F28069M: Lab01c

Manu Abraham
Genius 3510 points

Part Number: LAUNCHXL-F28069M
Other Parts Discussed in Thread: MOTORWARE

Hi,

I have a few questions, hopefully someone can help by answer them.

Running Lab01c, I get it running as described in the manual. I can increase the speed as well with gMotorVars.SpeedRef_krpm

But the maximum that I can increase it to is 5, ie 5,000 RPM. The motor as it is capable of running faster than that. When the speed is increased to 5.8 the motor stops running, though there is a PWM waveform on it's legs.

1. What causes the motor to stop ?

2. What can be done to increase the speed ?

3. Once the motor stops, I have to reduce the speed from 5.0 to 1.0 and then slowly increase the speed. If I set it to 5.0 as default, the motor will not start spinning at all. Why ?

Thanks,

Manu

  • 0
    TI__Expert 7325 points
    Hi Manu,

    The lab01c in motorware is only a closed current loop demo for signal chain verification. It does not run the instaSPIN-FOC FAST estimator for rotor position estimation. Instead, it uses a "open-loop" generated position information based on your speed setting.

    In order to achieve higher speed or better performance, you should run lab 2a to identify the motor parameter and lab 3a for the offset calibration, and use the rest of the labs (e.g. lab 4/5/11) to build your running system. Thanks.

    Han
  • 0 in reply to Han Zhang6
    Genius 3510 points
    Hi Han,

    Much appreciated, the fast and precise response. I think TI needs to give the documents a bit of love. All the information is there and more, but I feel that it is not organized properly. Trying to go through the documents scattered around, is a lot of pain. By the time you started poring over the documents, eventually, one looses track of what you started searching for in the first place. At first, I thought it might me alone. But trying to search using google, find that other people also are in the same situation. I understand clearly well, that it is a slightly wider area to completely understand, but I still feel that a bit of love to the documents could certainly make life a bit more easier for the people who are new to it.

    Thanks,
    Manu
  • 0 in reply to Han Zhang6
    Genius 3510 points
    Hi Han,

    Lab3a though it does the offset calibration, it does not run without the Ls_d and Ls_q values. Where do you suggest to get the Ls_d and _q values ?

    Thanks,
    Manu
  • 0 in reply to Manu Abraham
    TI__Genius 17175 points
    The Lsd/q values are gained in lab2x for motor ID. For PMSM that does not have saliency, the d/q values are the same. Lab2 identifies these and you can enter them into the user.h based on the results

    Sean
  • 0 in reply to Sean Bigley
    Genius 3510 points

    One of the issues that confuses me very much is that the estimated parameters vary project to project.

    Eg:

    // Lab 01b results
    -----------------------------------------------
    gMotorVars.Rr_Ohm        0.0
    gMotorVars.Rs_Ohm        0.411000699
    gMotorVars.Lsd_H        0.000709281012
    gMotorVars.Flux_VpHz    0.0327963568


    // Lab 01c results
    -----------------------------------------------
    same as above


    // Lab 02a results
    -----------------------------------------------
    gMotorVars.Rr_Ohm        0.0
    gMotorVars.Rs_Ohm        7.35280418
    gMotorVars.Lsd_H        0.000415586837
    gMotorVars.Flux_VpHz    0.0752419308


    // Lab 02b results
    -----------------------------------------------
    gMotorVars.Rs_Ohm        7.34800386
    gMotorVars.Flux_VpHz    0.127999991

    So, which one can be considered useful ?

    Thanks,

    Manu

  • 0 in reply to Manu Abraham
    TI__Expert 7325 points
    Manu,

    The lab 1b and 1c is not doing motor ID. What you need to consider is the result form lab 2.

    From the data you provided, it seems your motor have very low inductance and flux. lab2a and 2b are running the same code, just from different locations. Your variation if result may due to the low in inductance value. You can try to use the lab2c which is designed for low inductance motors. Try to run multiple times and you should be able to get values relatively close to each other. Then you can trust the result. Thanks.

    Han
  • 0 in reply to Han Zhang6
    Genius 3510 points
    Did that and it appears fine.

    Thanks,
    Manu