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tms320f28377s: stepper motor vector control

Jan Goris
Intellectual 780 points
Part Number: TMS320F28377S
Other Parts Discussed in Thread: CONTROLSUITE, C2000WARE, MOTORWARE

Hi,

i'm currently implementing a field oriented control motor platform. After following richard poleys control theory seminar and the "teaching old motors new tricks" i think i have a good understanding on how to pull it of. And at the moment i have a decent implementation thats works very good on a two pole pmsm motor i have. (i use encoder position feedback for the angle computation, no observer or FAST algorithm). But my goal is to be able to use this technology on the hybrid stepper motors we use in most of our projects. But i can't seem to get this algoritm stable on stepper motors... I use a PI controller to control the speed of the motor and this works very good on PMSM, but on stepper the moment my gain is high enough to get to the desired speed the loop gets unstable, so it appears i have to use a PID instead of PI regulator...

But does anybody have any idea why its working with PI on PMSM motors but not on hybrid steppers ?

Thanks for your input.

Regards

Jan

  • 0
    TI__Guru** 115440 points
    Both PI and PID can be used for stepper. There is a stepper example project in TI controlSUITE which use PI for current close loop. "\ti\controlSUITE\development_kits\DRV8412-C2-KIT_v131\Stepper".
  • 0 in reply to Yanming Luo
    Intellectual 780 points

    Hello Yanming,

    the project you refer to uses PI current regulation. I have this implemented also and it works just fine on both 2phase stepper and 3phase PMSM. But it is the velocity loop in a FOC setup i am having the problems with. So the output of the speed loop is the input for the q-axis current loop. This is stable and perfectly tunable for a pmsm in my setup but seems impossible on a stepper... But i don't know whats causing this difference...

    Regards

    Jan

  • 0 in reply to Jan Goris
    TI__Guru** 115440 points
    Yes, you can refer to the project to implement it on other phases stepper also. And you can use it for speed close loop also if you have speed sensor for stepper, only need to change the reference and feedback to speed, the output can be pwm duty or target current. You can find more detail information about PI in TI controlSUITE or C2000Ware (\libraries\control\DCL).
  • 0 in reply to Yanming Luo
    Intellectual 780 points

    Thanks Yanming,

    but i do know how to implement a PI regulator. It is only the tuning parameters of the stepper motor control loop that i can't seem to get stable in a FOC setup. It does work with a low pole count PMSM motor. So it must have something to do with the number of poles or the saliency of the motor. I was hoping somebody could point me in the right direction...

    Thanks again.

    Jan

  • 0 in reply to Jan Goris
    TI__Guru** 115440 points
    PI can be use for any motor for speed and current close loop control, not only low pole pairs PMSM. You need to know what's the input and output for PI, and set a right Kp, Ki for regulator.

    All lab projects for motor used PI in controlSUITE and motorWare, you download controlSUITE from TI website and refer to it. To adjust the Kp and Ki based your motor parameters and system.