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TMS320F28027F: How to change PWM frequency online?

Huihuang Chen
Expert 4060 points

Part Number: TMS320F28027F

Hi Champs,

Customer want to change the PWM frequency on line ( that means motor is running),

I cannot found " _EST_Obj_" structure define , does that means i  need to change the related parameter in "pUserParams" and call below function again ?

CTRL_setEstParams(obj->estHandle,pUserParams);

  • 0
    TI__Genius 17175 points
    Correct, you will not be able to locate the EST get/set functions as they are masked in the ROM code. You will need to call the setEstParams() function as you mentioned to update

    Sean
  • 0 in reply to Sean Bigley
    TI__Expert 4060 points

    Hi Sean,

    Thanks a lot for your reply!

    I have try modify the related parameter in pUserParams and call "CTRL_setEstParams(obj->estHandle,pUserParams)",but the motor will stopped .

    Could you using EVM to realize change PWM frequency online(when motor running).

    then  teach me how to modify the SW to implement  o support change PWM frequency online?

    it is better we can have the detail user guide  to teach customer how to realize change PWM frequency online.

  • 0 in reply to Huihuang Chen
    TI__Genius 17175 points
    Hi Johnson, as discussed offline it is currently not possible to change the PWM frequency while the motor is online, as calling CTRL_setEstParams() will set the estimator state to idle, thus stopping the motor. We will continue this discussion offline

    Sean
  • 0 in reply to Sean Bigley
    TI__Guru** 117160 points
    As Sean mentioned. It’s possible to change the pwm frequency as the steps you mentioned if the motor is stopping. But that will reset the FAST controller and stop the motor if it is running, because calling the CTRL_setEstParams(obj->estHandle,pUserParams) will set the estimator state to Idle and reset most variables in the estimator object. It seems the ROM version didn’t consider the requirement to change pwm frequency online without stopping the motor. That can't support the online changing pwm frequency in current version, we would like to consider it in the next generation version. Thanks.