• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 30 subscribers
  • Views 512 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.

DRV10963 control issues.

Jonathan Webster
Prodigy 30 points
Other Parts Discussed in Thread: DRV10963

I am currently using a drv10963 driver to run some prototype motors. The issue I am having is that one version of the motor will not lock on after the startup sequence. It seems that the sensorless control is unable to detect the rotation of the motor. We thought at first that it was the overcurrent protection kicking in but the other motors run at higher startup current and yet they work fine.

Would this be a motor caracteristic that I am missing? If so what would cause this behavior?

Thanks,

-Jon

  • 0
    TI__Guru** 114905 points

    Hi Jon,

    Are you seeing the motor in question repeating a spin up, stop cycle? If you are, it is due to insufficient BEMF when the device is transitioning from open loop (accelerate) to closed loop modes.

    Please refer to the section "SPIN UP SETTINGS" on pages 7 and 8 of the DRV10963 datasheet. During spin up the device will align the motor, then accelerate the motor in an open loop configuration until the device is driving the motor at the target speed (Hoffth).

    Once the target speed is reached, a decision is made to proceed into closed loop by examining the BEMF of the motor. If sufficient BEMF is available the DRV10963 will continue to spin the motor in closed loop. If not, then the DRV10963 will stop spinning the motor and try again to spin up.

    Can you provide any background information? What is your target application? Do you have any specifications that you can share on the working and non-working motor?

    Thanks.

  • 0 in reply to Rick Duncan
    Prodigy 30 points

    Thanks Rick,

    This is what I was suspecting. . . 

    Is there a way to up the BEMF on a motor? OR Is there a way to make the DRV10963 more sensitive to BEMF? We are using the DRV10963 eval board.

  • 0 in reply to Jonathan Webster
    TI__Guru** 114905 points

    Hi Jon,

    If you are running the motor <5V, you can try to raise Vcc to the recommended maximum of 5.5V. To do this you will need an external supply instead of the USB cable.

    Raising the voltage will cause the motor to spin a little faster at the open to closed loop transition point. This may be enough to spin the motor in question.

  • 0 in reply to Rick Duncan
    Prodigy 30 points

    Rick,

    I was already running it at full 5.5V. 

    Any other suggestions?

    -Jon