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TIDA-010054: Phase angle for 10kW output at Vin 700V and Vout 380V

Krishna Prasad
Prodigy 10 points
Part Number: TIDA-010054

In the TIDA-010054 reference design, a maximum phase shift of 23 degrees was suggested for a linear relation between phase shift and transferred power. Upon calculation for a 10kW output at Vin 700V and Vout 380V, we observed a 35 degree phase shift, which exceeds the initially suggested value.

In a new design our voltage ratios are significantly surpass the ranges covered in the reference design, could you kindly advise on the optimal phase shift value to be considered for the 'single phase shift' mode of operation?

Also, we request for email contacts for design discussion.

  • 0
    TI__Expert 4400 points

    Hi,

    23 degrees is the theoretically calculated value for 800V Vin 500V Vout. In reality, due to non-linearities, dead times etc. this value can varies.
    This also varies for different input and output voltages. 

    For a DAB maximum poser transfer happens at 90 degrees, so values up to 90 degrees can be used. The theoretically required phase shift can be calculated with equation 14 in the design guide:

    This formal give phase shift in rad:
    For our reference design it is: pi/2 * (1-sqrt(1-8*100kHz*35uH*10kW/(1.6*700*380))) = 0.65 rad = 37 degrees

    Hope this helps.

    Best regards,

    Andreas

  • 0 in reply to Andreas Lechner
    Prodigy 10 points

    Thanks Andreas Lechner. 

    Is it better to keep maximum phase shift to a low value like 23deg or 37deg as it was done in reference design for a practical design to reduce complexity?

    Thanks,

    Krishna Prasad 

  • 0 in reply to Krishna Prasad
    TI__Expert 4400 points

    Hi Krishna,
    There are two main reasons for selecting  lower maximum phase shift.

    1.  Linearity: The relation between Power and phase shift is non linear overall, there is a maximum at 90 degrees. But up to 23 degrees the relation is more liniear.
    2. Wider voltage ranges: As you can see both input and output voltage are part of this formula. So for lower output voltages for example more phase shift is required to achieve the maximum output power

    Best regards,

    Andreas