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TMS320F2800157: the PWM trig ADC to sampling the current and voltage signal , how to set delay of the sampl point to avoid the switching noise

zcwbj
Prodigy 80 points
Part Number: TMS320F2800157

Hi TI team:

   please help to confirm ,how to set the delay of sample point ot avoid the switching noise .

I am using the universal motor control lab solution to run my own board and motor.

but in Level 3, the motorVars_M1.speed_Hz can not follow the motorVars_M1.speedRef_Hz.

I check the current and voltage signal of ADC input ,find some switching noise.

So, I want to change the sampling point to avoiding the switching noise. 

please help ,how to change .  thanks a lot 

  • +1
    TI__Genius 10876 points

    Hello,

    If you're certain that the source of the issue is the ADC sampling point, refer to the function "HAL_setupPWMs" in the "hal.c" file. Near the end of the function, 'EPWM_setCounterCompareValue' is called for EPWM_COUNTER_COMPARE_C. Adjusting this value will adjust the sample point of the ADC.

    Regards,
    Jason Osborn

  • 0 in reply to Jason Osborn
    Prodigy 80 points

    Hi Jason

         I changed the sample point as below ,is it right.

    but in level 3 motorVars_M1.speed_Hz is still can not follow the motorVars_M1.speedRef_Hz

    but I check the actual current waveform with oscilloscope, the autual current frequence is right as below

    we have checked the ADC signal of the current and voltage ,we think the ADC signal is ok.

    Can you help to provide some suggestions , which factor can influenc the result of the est speed, how should we to solve the problem.

  • 0 in reply to Jason Osborn
    Prodigy 80 points

    Hi Jason：

            Also please help to confirm how to tunning the following 3 parameters

    what is the function of these 3 parameters ,do you have any document for detailed explanation

    thanks a lot !

  • 0 in reply to zcwbj
    TI__Genius 10876 points

    Hello,

    Apologies for the delay in response.

    First and foremost, I would verify that the motor-specific hardware parameters are correct. In the user_mtr1.h file, that's the following parameters:

    Most of these values can be found in the datasheet for the motor. Specifically, in the past, I've seen that a highly inaccurate value for USER_MOTOR1_INERTIA_Kgm2 can result in the estimator failing to function at all. Verify all of these parameters, but pay particular attention to that one.

    As for the 3 parameters you indicated in the second post, these parameters are used exclusively for Motor Identification in Build 4- they shouldn't impact performance in your system yet. Typically, they can be left at the default value. Tuning instructions for these can be found or derived from the InstaSPIN-FOC and IsntaSPIN-MOTION User's Guide (spruhj1i) if the identification process doesn't seem to work properly.

    Regards,
    Jason Osborn