• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 82 subscribers
  • Views 452 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

[instaspin] Acim motor does not reach maximum speed

TMS320F28027F: ACIM maximum speed

5263407
Prodigy 60 points

Part Number: TMS320F28027F
Other Parts Discussed in Thread: TMDSHVMTRINSPIN, , MOTORWARE

I have a related question on the topic "Acim motor does not reach maximum speed"

We are using the TMDSHVMTRINSPIN dev kit with the TMS320F28027F control card.

Our goal is to spin the motor at 3600rpms. To help us better understand controlling an ACIM we are using the motor shown in section 4.8 of the InstaSPIN-FOC User's Guide. We used the procedures outlined it section 4.8 to calculate the parameters and have completed the labs for FOC up to 5b.

But on the bench, with no load, the rpms top out at roughly 1300. When field weakening or powerwarp is enable higher speeds can be reached.

Questions:
1. Is it normal to have to use field weakening or powerwarp for achieve the 2x time rated speed?
2. Are there other parameters that factor into motor speed?
3. Is that more information I can provide?


Thanks,
Rob

  • 0
    TI__Guru** 117260 points

    1. Yes. The maximum speed depends on the specification of the motor and the added load on the motor, you have to use filed weakening or increase the dc bus voltage if you want to run the motor up to the rated speed. Not sure if the maximum speed of the motor can be achieved twice rated speed which is related to load and spec. of the motor.

    2. No, just the flux.

    3. The torque output will be reduced with the speed increase during constant power control.

  • 0 in reply to Yanming Luo
    Prodigy 60 points

    Thank you.

    • We have been reviewing other posts on TI's E2E forum regarding ACIM control. And we see following statements:
    • you would have to use field weakening or powerwarp to achieve the 8x time rated speed you desire. (Mar 20, 2017)
    • Field Weakening - It's only tested on PMSM, not recommended for ACIM (Sep 27, 2019)
    • yes, you need to add the Field Weakening. We can just give you some advice, but we didn't test it on a real motor. (Oct 23, 2019)
    • When are you planning to add the function of the Field Weakening for induction motors to InstaSPIN? (Nov 6, 2019)

    Not any plan yet since it's not necessary for most ACI motor applications.

    • Yes. The maximum speed depends on the specification of the motor and the added load on the motor, you have to use filed weakening or increase the dc bus voltage if you want to run the motor up to the rated speed. Not sure if the maximum speed of the motor can be achieved twice rated speed which is related to load and spec. of the motor. (Jun 2, 2020)

    So, for ACIMs - which should be used - field weakening or powerwarp?

    In terms of the Motorware library, what is the difference between the two?

    Regard,

  • 0 in reply to 5263407
    TI__Guru** 117260 points

    Powerwarp uses a similar method as the filed weakening control by decreasing the Id rated current for ACIM. You might know that the output torque will be decreased if the motor run-up to the rated speed with PowerWarp or Field weakening. So please know what's the created speed of the motor and what load is added on the motor.

    You might check if the gMotorVars.Vs is close to the USER_MAX_VS_MAG_PU. If yes, increase the bus voltage to see what happens.

    https://e2e.ti.com/support/microcontrollers/c2000/f/171/p/905810/3363130

  • 0 in reply to Yanming Luo
    TI__Guru** 117260 points

    Just wanted to check in and see if there is any update from your side, I’m assuming you were able to resolve your issue. We would like to close this thread, please let me know if you have any questions. Thanks.

  • 0 in reply to Yanming Luo
    Prodigy 60 points

    On the topic of AC induction motor control there seems to be some inconsistencies on this forum regarding this topic.

    We are now at the point where we need to fully understand the relationship between MOTOR_MAGNETIZING_CURRENT, Field Weakening, and Powerwarp as it relates to our motor application.

    We plan to reach out to our local TI rep for on-site support.

    You can close this thread.

    Thank you