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DRV10983: we have made a PMSM motor and still facing the issue

Part Number: DRV10983

Hi Team, 

May I ask for help? This concern was a continuation of the other post below:

(+) DRV10983: getting stopped in open loop - Motor drivers forum - Motor drivers - TI E2E support forums

We still got a response from our customer as shown below:

"as per advise, we have made a PMSM motor and still facing the issue

To brief the problem - we are using EVM of DRV10983 to rotate the BLDC motor of the ceiling fan, but we couldn't rotate it at the desired frequency/rpm.

Earlier we were using reluctance motors and as suggested we designed a new PMSM motor. Even, in that also we are facing a similar issue.

Please find the attachment "BLDC-PMSM_AsPerEarlierSuggestions.pdf" we used by following the instructions in the below training videos,
Part-1 training.ti.com/how-spin-drv10x-family-devices-part-1
Part-2 training.ti.com/how-spin-drv10x-family-devices-part-2

BLDC-PMSM_AsPerEarlierSuggestions.pdf

Kindly help us! We are looking for a motor to rotate at 370rpm but it is not exceeding 210rpm. Also, as said in the part-2 video can you share with us the tutorials which explain the significance/guidance for tuning the other parameters."

I hope you can further assist us. Thank you so much.

Kind regards,
Gerald




  • Hi Gerald,

    Thanks for posting your question in E2E forum. Can you answer below questions to help us understand the issue better?

    1. What is the phase current drawn by the motor at 210 rpm.
    2. What is the phase resistance, inductance, BEMF constant and pole pairs of the motor?
    3. Can you share the current EEPROM register settings.
    4. Do you see any faults triggering above 210 rpm or does the motor spin only up to 210 rpm at 100% speed command? 

    Please refer to the DRV10983 Tuning guide for more information related to tuning the motor.

    Regards,

    Vishnu

  • Hi Vishnu,

    Thank you for your help. We are now waiting for our customer response. We will keep you updated. Thank you.

    Kind regards,
    Gerald

  • Thanks Gerald!

  • Hi Matt,

    Hi Vishnu,

    Sorry for taking to long to reply. I just received a response from our customer:

    1) What is the phase current drawn by the motor at 210 rpm.
    Phase current = 1.34@210 RPM

    2) What is the phase resistance, inductance, BEMF constant and pole pairs of the motor?
    Phase Resistance = 2
    Inductance = 0.0021H
    BEMF = 16.26 (Vrms)
    Pole Pairs = 7

    3) Can you share the current EEPROM register settings.
    I have attached the current EEPROM settings for the 210RPM as EEPROM_210RPM.pdf

    4) Do you see any faults triggering above 210 rpm or does the motor spin only up to 210 rpm at 100% speed command?
    We are getting Lock Code 0 (Current Limit)

    I hope you can further help us.

    Kind regards,
    Gerald

  • Hi Gerald,

    Thanks for sharing the details. I see from the BEMF plot that the peak voltage is around 22V and frequency of the BEMF voltage is 25 Hz (10 ms /div on the scope). Kt will be 22/25 = 880 mV/Hz. If this is correct then the programmed Kt should be changed to 880 mV/Hz.

    Please try below recommendations.

    1. Change programmed Kt to 880 mV/Hz.

    2. Increase the driver dead time to 800 ns.

    3. Keep tuning the lead time till the speed reaches rated speed. 

    Regards,

    Vishnu