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TMS320F28075: How to solve the initialization phenomenon when implementing interleaved control with 2 PSFB control modules

kibeom kim
Prodigy 10 points
Part Number: TMS320F28075


Tool/software:

Hello, I am a user using TMS320F28075.

I want to implement interleaved control of 2 PSFB modules as below. If there is a solution, please help me.
※ Problem
- When the On duty section of EPWM10 exceeds 50%, that is, 0 or 6000 of TBPRD, 1pulse is initialized and control starts again.

1. Settings
1.1 Synchronize EPWM10 to EPWM7 (using TI provided function)
1.2 EPWM7,8,9,10 PWM settings
- Count mode: up-count
- TBPRD: 6000; (20kHz operation)
- EPWM7&8 TBPHS = 0;

- EPWM9&10 TBPHS = 1500;(90 degree phase delay)
- CMPA : 3000;(50% duty set to drive PSFB)
- AQCTLA.ZRO = AQ_SET;(High according to CMPA)
- AQCTLA.CAU = AQ_CLEAR;(Low according to CMPA)
- DBCTL.POLSEL = DB_ACTV_HIC;(Active Hi Complimentary)
- DBRED & DBFED : 36;

- In case On duty : 0%

- In case On duty : 50%

- I assume it occurs because it decreases below 0 in the section shown below.

  • 0
    TI__Mastermind 24650 points

    Hello,

    Thank you for your inquiry. Please allow another day for me to form my response. Appreciate the patience!

    Best Regards,

    Allison

  • 0
    TI__Mastermind 24650 points

    Hello,

    Thanks for the patience in me assessing the inquiry- I think I still need more clarification on the nature of the issue. In the second figure, are you implying that the EPWM10B red edge is missing and the EPWM output remains high for an undesirable long time (until the next falling edge)? I'm not sure what you mean by the pulse being "initialized" as you say here:

    kibeom kim said:
    1pulse is initialized

    When you say that on time is "greater than 50%" causes an issue, do you mean that when the EPWM10 CMPA value reaches 3000 or greater, this causes the issue to occur? This wasn't clear from the first statement:

    kibeom kim said:
    that is, 0 or 6000 of TBPRD

    Apologies if I am misunderstanding - just want to make sure I have full clarity on the symptoms of the issue.

    Best Regards,

    Allison