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CCS/TMS320F28027: HVPSFB-Calculations

xufeihx
Intellectual 500 points

Part Number: TMS320F28027

Tool/software: Code Composer Studio

Hello

in the HVPSFB-Calculations TI's HVPSFB kit,there’s

Kv

0.5008

How did get this number Kv=0.5008?Where the 0.5008 come from?

Thanks a lot,

-xufeihx

  • 0
    TI__Guru* 84840 points

    Please take a look at this post https://e2e.ti.com/support/microcontrollers/c2000/f/171/p/223618/788526?tisearch=e2e-sitesearch&keymatch=KvQX#788526 that goes into some detail on the meaning of the variables.  Much of the first few tabs on that spreadsheet are used to convert the real world voltages into the correct Q format and corresponding ADC output from the C28x.

    Best,

    Matthew

  • 0 in reply to MatthewPate
    Intellectual 500 points

    Hi Matthew,

    Thanks very much for your reply. 

    I have another question that there should are the EPWM1 drive Q2Q3 and EPWM2 drive Q1Q4 in HVPSFB_User's Guide_v1.1 for PCMC mode

    1,In Figure 1. A Phase Shifted Full Bridge circuit and Figure 2. PSFB PWM Waveforms:The left leg(QA- QB leg)  is the ‘Active to Passive’ leg,and the right leg(QC- QD leg)  is  the ‘Passive to Active’ leg..

    2,,In Figure 12. PCMC PWM Waveforms:The right leg(Q2- Q3 leg)  is the ‘Active to Passive’ leg,and left leg(Q1- Q4 leg)  is  the ‘Passive to Active’ leg..

    3,On Page 5,it said:

    Figure 3 shows a simplified block diagram of the PSFB circuit implemented on the HVPSFB board. Switches QA, QB, QC and QD in Figure 2 correspond to switches Q1, Q4, Q2 and Q3 respectively

    i.e.,QAQB=Q1Q4 and QCQD=Q2Q3,

    I think there's a wrong.

    4,On the Figure 10.HVPSFB Base Board Schematic the EPWM1 drive Q1Q4 and EPWM2 drive Q2Q3.

    But I think if item 1 is right,then there should are the EPWM1 drive Q2Q3 and EPWM2 drive Q1Q4

    Ple help me ,thank you

    xufeihx

  • 0 in reply to xufeihx
    TI__Guru* 84840 points

    Xufeihx,

    I'm not sure I understand, after looking at the documenation and schematic ePWM1A/B are definitely controlling switches Q1/Q4(Qa/Qb) as shown in the conceptual circuit and schematic.  ePWM2A/B are controlling Q2/Q3(Qc/Qd).

    Also, Q1/Q4  are in parallel with Vin/Vbus into the DC/DC so that would also confirm they are primary switches, correct?

    I beleive the Figure 12 is showing Q1/Q3(diagonal pair) on at the same time until peak ref current is hit, at which time Q3 goes low and Q2 goes high with some deadband.  I don't think that Figure 12 is contradicting the earlier figures or schematic.

    Best,

    Matthew