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LAUNCHXL-F28069M: Instaspin Lab04a with discrete resolver code

Sunghyun Park
Prodigy 20 points

Part Number: LAUNCHXL-F28069M
Other Parts Discussed in Thread: C2000WARE

Hi,

I'm setting up the F28069M registers for the DIY inverter.

My plan is to do field-oriented current control using the discrete resolver.

So, I'm modifying the Instaspin Lab04a base code making an excitation signal for the discrete resolver.

EPWM1, 2,3 have 10kHz frequency for each phase of gate drive signal with ADC interrupt and EPWM4 has 175.78kHz frequency for the excitation signal with ADC interrupt

Since I turn on the gate PWM, EPWM4 interrupt has a weird delay periodically(3.35kHz) (see the yellow arrow below picture)

 

Let me know if anyone knows what caused it.

  • 0
    TI__Guru** 117110 points

    How many interrupts are enabling in your project? Do you enable the interrupt nesting if there are multiple ISRs in your project. You might refer to the example in the folder of the C200Ware as below for interrupt nesting.

    C:\ti\c2000\C2000Ware_3_04_00_00\driverlib\f28004x\examples\interrupt

  • 0 in reply to Yanming Luo
    TI__Guru** 117110 points

    Just wanted to check in and see if there is any update from your side, I haven’t heard from you for two weeks, so I’m assuming you were able to resolve your issue. Please let me know if you have any questions. We would like to close this thread if no any further questions. Thanks.

  • 0 in reply to Yanming Luo
    Prodigy 20 points

    Although I checked interrupts in my code, I wasn't able to find any 3.3kHz interrupt routine.

    but I found some of code(ETPS) in "hal.c" makes this weird delay.

    Could you explain what is the purpose of ETPS?

    ======================================Original code===================================

    // setup the Event Trigger Prescale Register (ETPS)
    if(numPwmTicksPerIsrTick == 3)
    {
    PWM_setIntPeriod(obj->pwmHandle[PWM_Number_1],PWM_IntPeriod_ThirdEvent);
    PWM_setSocAPeriod(obj->pwmHandle[PWM_Number_1],PWM_SocPeriod_ThirdEvent);
    }
    else if(numPwmTicksPerIsrTick == 2)
    {
    PWM_setIntPeriod(obj->pwmHandle[PWM_Number_1],PWM_IntPeriod_SecondEvent);
    PWM_setSocAPeriod(obj->pwmHandle[PWM_Number_1],PWM_SocPeriod_SecondEvent);
    }
    else
    {
    PWM_setIntPeriod(obj->pwmHandle[PWM_Number_1],PWM_IntPeriod_FirstEvent);
    PWM_setSocAPeriod(obj->pwmHandle[PWM_Number_1],PWM_SocPeriod_FirstEvent);
    }

    ================================================================================

    ======================================Edited code===================================


    // setup the Event Trigger Prescale Register (ETPS)

    PWM_setIntPeriod(obj->pwmHandle[PWM_Number_1],PWM_IntPeriod_ThirdEvent);
    PWM_setSocAPeriod(obj->pwmHandle[PWM_Number_1],PWM_SocPeriod_ThirdEvent);

    ================================================================================

  • 0 in reply to Sunghyun Park
    TI__Guru** 117110 points

    This programs the event prescaling options, which means an event will be trigger every one, two, or three PWM cycles.

    You might take a look at chapter  3(Enhanced Pulse Width Modulator (ePWM) Module) of F2806x TRM if you want to know more about EPWM.