• State TI Thinks Resolved
  • Locked Locked
  • Replies 10 replies
  • Answers 2 answers
  • Subscribers 33 subscribers
  • Views 761 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.

DRV10970: The motor is not rotating at it's maximum speed

Danilo A.
Mastermind 30020 points
Part Number: DRV10970


Hi Team, 

We have a customer using DRV10970 to drive the WS7040-12-X200 blower motor. However the motor is not rotating at it's maximum speed even if they drive the device at the maximum PWM. 

The hall effect sensors are configured like in Figure 23 of the datasheet. They set J3 and J4 between 1-2 and populated 1k ohm to R17, R18 and R19. They connected the 2 pins on J5, J7 and J8. 

How can they configure the evaluation board to drive the motor at maximum speed?

Regards,

Danilo

  • 0
    TI__Mastermind 21805 points

    Hello Danilo,

    I have a couple of ideas to check on the DRV10970EVM:

    • Are they using trapezoidal or sinusoidal commutation (CMT_MOD, J3 on the board)? - it looks like they are pulling it high for sinusoidal control. Some trapezoidally-wound motors will not hit their maximum speed when using sinusoidal commutation.
    • What is the state of the DAA pin (J4 on the board)? Is Adaptive drive angle adjust enabled? - it looks like they have selected the 5 degree drive angle with 30 degree Hall placement (no ADAA) - this could be incorrect based on their motor construction.
    • --> try the following settings:
      • CMT_MOD J3 ground (jumper between positions 2 & 3), DAA pin J4 floating (remove jumper). This should be trapezoid control
      • CMT_MOD J3 floating (remove jumper), DAA pin J4 floating (remove jumper). This should be sinusoidal control with 0 degree Hall placement and ADAA enabled.
      • CMT_MOD J3 VINT (jumper between positions 1 & 2), DAA pin J4 floating (remove jumper), and J4 ground (jumper between positions 2 & 3). This should be sinusoidal control with 30 degree Hall placement and try 0 degree and 10 degree lead angle adjustment.
    • Can you check to see if the CS (current limit) is high enough to support the maximum motor current? This is R16 on the EVM and is by default 24k, this corresponds to an ILIM of 1.25A.
    • --> try the following settings
      • Decrease the value of R16 to allow higher current flow in the motor.

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    TI__Mastermind 30020 points

    Hi Matt,

    Thank you for your suggestions. The customer implemented your suggestions and changed R16 to 10k. After that they were able to drive the motor but the motor is still not running at maximum speed.

    If the potentiometer value is low (minimum pwm signal) the motor can’t rotate smoothly and after a while the motor stops. The minimum current consumption is 0.05A at 12V supply voltage. He had checked the hall sensor signals are correct. Any suggestions?

    Regards,

    Danilo

  • 0 in reply to Danilo A.
    TI__Mastermind 24415 points

    Hi Danilo,

    Good to know that the customer is now able to spin the motor. Did customer try leaving DAA pin floating? This enables adaptive drive angle adjustment mode. If the drive angle is off by few degrees then the motor might not be able to reach maximum speed. 

    Regards,

    Vishnu

  • 0 in reply to Vishnu Balaraj
    TI__Mastermind 24415 points

    Hi Danilo,

    Just wanted to follow-up with you to see if you have any updates

    Regards,

    Vishnu

  • 0 in reply to Vishnu Balaraj
    TI__Mastermind 30020 points

    Hi Vishnu,

    According to the customer, they have tried all the connection options for DAA such as floating, connected to GND and VINT but the motor is still running below its maximum RPM and sometimes they need to manually rotate the motor to start the rotation.

    Regards,

    Danilo

  • 0 in reply to Danilo A.
    TI__Mastermind 24415 points

    Hi Danilo,

    ADAA mode works only when a 0° phase difference exists between hall signal and BEMF. ADAA feature can be configured by connecting the CMTMOD pin to ground (0° mode) and leaving the DAA pin floating (ADAA mode).Please check section 2.1 in this App note for more info on how to configure for ADAA.

    Regards,

    Vishnu

  • 0 in reply to Vishnu Balaraj
    Prodigy 20 points

    Hello! I am  Eren,

    Firstly I want to say thank you! We tried your suggestions and we took some way on the project, but now our main problem is sometimes we start the motor but hasn't any move and drv10970 evm module open the led 2.I forced the motor for rotating and  motor start rotating. This forcing issue is big problem. I checked the hall sensors signal and there is no problem. I hope I explain our problem correctly. I am waiting your replys. 

    Best Regards.

    Eren

  • 0 in reply to Eren Sevilmis
    TI__Mastermind 21805 points

    Hi Eren,

    FYI - We are having severe inclement weather in Dallas and multiple affected team members are without power. Please be patient with our response here.

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    Prodigy 20 points

    Hi Matt,

    I am sorry hear about  that. I hope weather conditions will be normal as soon as possible. 

    Have a nice day!

    Eren.

  • 0 in reply to Eren Sevilmis
    TI__Mastermind 24415 points

    Hi Eren,

    LED2 turns on when there is a lock condition. Lock condition gets triggered if the Hall signal stops toggling for a certain period of time. Can you manually spin the motor to double check if hall signals are generated by the IC?

    Regards,

    Vishnu