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TMS320F28P550SJ: EPWM configuration for three-Phase Interleaved LLC

Johnny Chen
Expert 4980 points
Part Number: TMS320F28P550SJ


Tool/software:

Hi Champ,

I am asking for my customer.

They are developing three phase LLC as below figure with type-4 EPWM.

Which EPWM configuration would the EPWM expert recommend it ? By using the phase shift method or using CMPA/CMPB (as sprad15.pdf proposed) in such topology ?

Which and why?

Thanks, 

Johnny

  • +1
    TI__Expert 3620 points

    We recommend the CMPA and CMPB to do phase shifting operation since this will enable to use same time base counter all synced with each other while use compare method to generate phase shift and duty. In applications like LLC operating at high/wide frequency range is required for soft start and light load operation, you can use HRPWM finer steps (as low as 75ps or 150ps) to control CMPAHR and CMPBHR to generate precise phase shift and 50% duty. Also this allows flexible operation for llc to control duty, phase, period and dead band in up-down counter mode where controller can update TBPRD, CMPAHR and CMPBHR to control gain, phase shift and duty of the waveform.

    Regards,

    Sumit