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DRV8353: DRV835x - any way of detecting a motor is not connected?

Sorin Cracana
Prodigy 100 points
Part Number: DRV8353
Other Parts Discussed in Thread: TMS320F280049C

Hi,

We're using MS320F280049C & DRV8353S  to FOC control a motor (InstaSPIN & FAST).

We would like to detect when a motor is not present/connected and report it.

Do you recommend any way of doing this using these software/hardware components?

  • 0
    TI__Mastermind 18981 points

    Hi Sorin, 

    Will let Aaron from our team comment further upon reviewing the above hardware and software combination. 

    In the meantime, can you tell us a bit more about when the detection is attempted?

    • (e.g. are you checking if motor is connected while system is entirely at rest and not spinning? or are you trying to have the system detect this while the motor is still expected to be actively spinning but suddenly disconnected?) 

    Not directly related, but below videos provide info of how to detect the motor's initial position & example test procedure, so if your MCU executes these test patterns and gets an invalid result on motor position, it could be a feasible way of detecting that the motor is not connected. 

    Best Regards, 
    Andrew 

  • 0 in reply to Andrew Liu
    TI__Mastermind 26046 points

    Hi Sorin,

    DRV835x does not have open load detection, so you'll have to get creative and create an "open load" test from the TMS320F280049C. 

    Here's an idea: when a motor is unconnected, you will see 0-A current through the CSAs if you source current through one half-bridge and sink it out the other. So let's say you pulse INHA/INLA = 20%, and INLB = on, so motor current flows from A --> B. If a motor is present, this will yield a current out of SOB (i.e. 500mA), and if a motor is not present, then current from SOB = 0A. If it is under a threshold, the motor is disconnected, and if it is over the threshold, then the motor is connected since the current path is continuous.

    Ensure you do not pulse this current for long so that the motor does not align, but can be sampled by the ADC. 

    Hope this helps,
    Aaron