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TMS320F28377D: PROBLEM IN EPWM MODULE

SAGAR NENA
Prodigy 40 points
Part Number: TMS320F28377D

Facing Problem in EPWM Module.

I am using UP Counter Mode Switching freq is 3.6khz For Booster Converter.

So According to that TBPRD VALUE IS:27776

Configuration :Pulse output high When TBCTR=CMPA. and Pulse output Low When TBCTR=TBPRD.

Case 1:Control Mode

   Load Value in CMPA=12276

   So according to that my output Pulse should be like this

   On Time:155us

   Off Time : 122us

   I am getting output as per above:

Case 2: Power Mode

   Load Value in CMPA=12276

   So according to that my output Pulse should be like this

   On Time:155us

   Off Time : 122us

   I am getting output as per below:

   On Time:88us

   Off Time : 197us

Here is the question I have Load Same Value in power and Control Mode But I am getting Different Result in Both The Case?

So what is the Cause of this Problem.

Kindly Suggest.

  • 0
    TI__Mastermind 23320 points

    Hi Sagar,

    Are there any other differences in your configuration for control and power modes? Have you connected the pwm output to anything or are you currently measuring the on and off times through an oscilloscope directly from the device pins?

    Also, would you please post your configuration code, if possible, or the control and power modes?

    Best Regards,

    Marlyn

  • 0
    Prodigy 40 points

    Hi Marlyn,

    1.Are there any other differences in your configuration for control and power modes?

    Ans: No There is No Difference in Configuration in Control and Power Mode.

    2.  Have you connected the pwm output to anything or are you currently measuring the on and off times through an oscilloscope directly from the device pins?

    Ans: I have connected Pwm output in IGBT Driver And Measuring Pulse On Oscilloscope on Directly on Device pins as well as on igbt Gate Pin.

    Code Configuration:

    EALLOW;

    EPwm4Regs.AQSFRC.bit.RLDCSF=3;

    EPwm4Regs.TZSEL.bit.OSHT3 = 1; //enable tz3 interrupt

    EPwm4Regs.TZCTL.bit.TZA = TZ_FORCE_LO;

    EPwm4Regs.TZCTL.bit.TZB = TZ_FORCE_LO;

     EPwm4Regs.TZEINT.bit.OST = 1;

    EDIS;

    // Setup TBCLK

    EPwm4Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP;

    EPwm4Regs.TBPRD = EPWM4_TBPRD ; // Set timer period

    EPwm4Regs.TBCTL.bit.PHSEN = TB_DISABLE; // Disable phase loading

    EPwm4Regs.TBPHS.bit.TBPHS = 0x0000; // Phase is 0

    EPwm4Regs.TBCTR = 0x0000; // Clear counter

    EPwm4Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // Clock ratio to SYSCLKOUT

    EPwm4Regs.TBCTL.bit.CLKDIV = TB_DIV1;

    // Setup shadow register load on ZERO

    EPwm4Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;

    EPwm4Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;

    EPwm4Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO;

    EPwm4Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO;

    //Compare Resistor Load

    EPwm4Regs.CMPB.bit.CMPB = 12276;

    //Set Action Function Called Only Once

    EALLOW;

    EPwm4Regs.AQCTLB.bit.PRD = AQ_CLEAR;

    EPwm4Regs.AQCTLB.bit.CBU = AQ_SET; // OR .PRD

     

    EPwm4Regs.TZCLR.bit.OST = 1;

    EPwm4Regs.TZCLR.bit.INT = 1;

    EPwm4Regs.TZEINT.bit.OST = 1;

    EDIS;

     

    There is Only On Difference In Control And Power Mode:

    -In Control Mode DC Voltage is Not Given To IGBT While Switching.

    -In Power Mode DC Voltage is Given To IGBT While Switching.

  • 0 in reply to SAGAR NENA
    TI__Mastermind 23320 points

    Hi Sagar,

    I do not see any issues with the configuration code you have attached. Have you tried debugging things from the IGBT side? Does this happen for all DC voltages provided to IGBT while switching?

    Best Regards,

    Marlyn