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DRV8301-69M-KIT: current control with lab11e; limit rpm; motor behaviour

Daniel Mueller
Intellectual 916 points
Part Number: DRV8301-69M-KIT
Other Parts Discussed in Thread: DRV8301

Hey TI,

I have a few questions again.

1. Is it possible to use lab11e with current control instead of speed control?
If yes, what do I have to change?


2. I’m very interested in how one can limit the rpm in current control mode? I’ve searched about few threads, but I didn’t find an answer.


3. I added a current ramp in lab5a because my motor was stuttering/jerking if I increased iqref_A too fast.
But that wasn’t the problem, as I know now. It’s still the same behaviour with or without ramp.
Until 60A it works perfectly, but when iqref_A is between 60 and 80 ampere the motor begins hard stuttering/jerking.
The first thing I thought of was that I had not used enough load. Because of that I tried driving uphill but still the same behaviour. Different Kp and Ki did not change anything either.
Do you have any ideas what that could be?
I read in a thread that the Ls is maybe changing when high current flows. Would this be a possibility?

The motor specs are 50V 80A and I use the drv8301 kit(my own hw is not finished as of yet).
I changed the current scaling to 1mohm and the board is cooled.


also I have to say I’m happy with Instaspin. My vehicle is working quite well already.


thanks in advance

  • 0
    TI__Guru** 115470 points
    1. Yes, but you have to change some codes to disable the speed loop, to adjust gIdq_ref_pu.value[1] as your required.
    2. You may limit or adjust the reference current to limit the speed likes using speed close loop control.
    3. You'd better to know the rated and maximum speed of the motor, the motor is difficult to run smoothly if you add so high current without any load and motor speed is higher than maximum speed.
    Ls will be changed very slightly that didn't have a large impact on motor control, you may checked with motor manufacturer to know the Ls vs. Current curve.
  • 0 in reply to Yanming Luo
    Intellectual 916 points
    Thank you Yanming,

    Regarding 3:
    I should have told you that the motor speed is not higher than its max speed.
    And it’s not only at high speeds it’s also at lower speeds . To make sure that I was producing enough load I drove uphill. Do you think that’s still not enough load?

    It’s pretty strange because up to 60A it works perfectly, and then suddenly it begins to shake.
    I will just try some more things and ask the motor manufacturer about the Ls/cc.
  • 0 in reply to Daniel Mueller
    Intellectual 916 points
    Now it works perfectly!!! I only changed the PWM frequency from 20Khz to 45Khz and increased Kp and Ki a bit.