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DRV8308EVM: What are the settings that will allow torque control at zero speed?

Stephen Bellio
Prodigy 10 points
Other Parts Discussed in Thread: DRV8308EVM, DRV8308, DRV8301, DRV8313

I plan to use the DRV8308EVM with a maxon motor that has halls and encoder. A controller will read the encoder position and output CLK and DIR. After connecting the motor and controller to the DRV8308EVM there was a problem even when just commanding pwm mode. The problem is that when running zero speed under a small load, the torque cuts out intermittently and the FAULTn and LOCKn LEDs turn on.   This also happens with the DT4269 motor and the DRV8308EVM_GUI in PWM mode. What are the settings that will allow torque control at zero speed?

Thanks,

Stephen

  • 0
    TI__Mastermind 20985 points
    Stephen, I think I understand what you're describing. Are you saying that in PWM mode, if the commanded duty cycle is small (10%), the motor doesn't turn well and the DRV8308 detects a fault?

    The DRV8308 isn't designed to turn motors at around zero speed. The duty cycle needs to be high enough to overcome the starting torque.

    If you need to turn a BLDC very slowly, I think you'll have better results using a device with independent half-H bridge control, such as the DRV8313 or DRV8301/2/3/5.

    Best regards,
    RE