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TMS320F28069M: Current limiting with DRV8305 motor controller

William Barnard
Prodigy 20 points

Part Number: TMS320F28069M
Other Parts Discussed in Thread: DRV8305, MOTORWARE,

Hi,

I am using the TMS320F28069M and a DRV8305 motor driver, and we have the Motorware libraries installed. I dug through the DRV8305 datasheet hoping that there was a simple way to implement current limiting to the motor. The options relating to current limiting seemed to be 1: shut off and send a warning. 2: dont shut off but send a warning. 3: dont shut off or send a warning. Due to the nature of the project, a hard shut-off is not acceptable and we are looking to limit the current to the motor, but allow it to continue running at max current indefinitely. Our main ISR on the TSM is running at 100Hz which is slower than we would want for a current limiting loop but changing that frequency is out of the question. What options exist for implementing current limiting as described in this application using the motorware libraries? Which of the Labs would you suggest I look at?

  • 0
    TI__Guru** 116860 points
    You can find the "InstaSPIN Projects and Labs User’s Guide" in motorware, and follow the guide to use lab02b/lab02 to identify the motor parameters first, use lab05b or lab10a to spin the motor. There are some lab projects base boostxl-drv8305 kit which can be a reference for you.
    Set the Vds level in the VDS Sense Control register of DRV8305 to change the current limiting.
  • 0 in reply to Yanming Luo
    Prodigy 20 points

    Hi Yanming,

    Thank you for your help, I've got the motor spinning and speed control is working well. I tested with the VDS sense control and the motor does shut off when above the threshold, however I would like to have the motor stay on at max current rather than shut off. I also tried changing the USER_IQ_FULL_SCALE_CURRENT_A  in user.h but this also acted as a shut off rather than a current control. Are there provisions within motorware to run in speed control mode but limit the current at a specified value?

    Thanks,
    Will

  • 0 in reply to William Barnard
    TI__Guru** 116860 points
    Set the "USER_MOTOR_MAX_CURRENT" in user.h to limit the torque current which is the maximum output of speed PI regulator.