• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 82 subscribers
  • Views 492 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TMS320F280049: TIDA-010054 Three trivial questions about software codes

TMS320F280049: TIDA-010054: last few questions

Liu Zijian
Prodigy 70 points

Part Number: TMS320F280049

Hi, 

    The codes below are the  DAB_pwmPhaseShiftPrimSec_ticks under the case of "leading phase":


    DAB_phaseSyncPrimToSecCountDirection = EPWM_COUNT_MODE_UP_AFTER_SYNC;
    DAB_pwmPhaseShiftPrimSec_ticks = DAB_pwmPhaseShiftPrimSec_ticks * -1;

    DAB_pwmPhaseShiftPrimSec_HiResticks = ((uint16_t) 0xFF - ((uint16_t)(DAB_pwmPhaseShiftPrimSec_ticks & 0x0000FFFF)>>8));

    DAB_pwmPhaseShiftPrimSec_ticks =
    ((DAB_pwmPhaseShiftPrimSec_ticks & 0xFFFF0000) + 0x10000) + (DAB_pwmPhaseShiftPrimSec_HiResticks << 8);

I see that it indicates that (integer+1).（255-decimal）, but I cannot understand its principle. Hope you can help clarify, thanks.

BTW, in the isr1, the DAB_gvOut is restricted in [0,0.7] instead of [-0.7, 0.7].

Zijian

  • 0
    TI__Mastermind 43730 points

    Zijan,

    This is highly related to how we have implemented this on our IP and i cannot disclose all the details for the high resolution phase shift implementation. 

    However if you see any issue with the pulses being generated etc we can definitely have a look. 

    At a broad level, because we have delay line we can always delay the signal never advance it. Hence we need to comprehend the phase delay as an advance on another signal and hence the calculation differences. 

    On the ISR1, we did not have access to bi-directional supplies and wanted to avoid power flow back to the power supply in case it can cause damage. Hence we limit the phase shift to 0

    -Manish 

  • 0 in reply to Manish Bhardwaj
    Prodigy 70 points

    Thanks a lot. I will not ask any further about the leading phase.

    However, I am puzzled now: why the bi-directional is not accessible? Isn't is a dual active bridge designed for bi-directional energy flow?

  • 0 in reply to Liu Zijian
    TI__Mastermind 43730 points

    It is accessible if you have the hardware to test in fully bi-directional manner. Unfortunately we did not have access to one, hence we tested one direction with one set of values and the other direction with another set of values. Also i think the reverse direction is only provided in open loop code.