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TIDA-00777: clarification on the "Phase error observed"

AnBer
Mastermind 29320 points
Part Number: TIDA-00777
Other Parts Discussed in Thread: TIDA-00222, TINA-TI

Team,

Regarding TIDA-00777 - "Active Integrator for Rogowski Coil Reference Design With Improved Accuracy for Relays and Breakers - TIDUBY4A":

-Referring to page 24, 26, 27 and 29:
What do you mean by “Phase error observed” and how do you calculate/measure it?
What are the signals you refer to and at what point of the TIDA-00777 are they measured?

-For example:
At page 24 you mention 90 uS
At page 29 you calculate 499.7uS
What does the 90uS refer to? Are you talking about the phase error introduced by the integrator (phase error would be equal to 90°-atan(2×pi×f×RC)) ?
Where do you take into account the tolerance of the electronic components?

Thanks in advance,

Anthony

  • 0
    TI__Guru*** 144939 points

    Hello Antony 

    Please refer to section 3 that describes phase error calculations.

    In the design we have showcased 2 paths, one for precision measurement and the other for fast startup.

    The delay refers to the phase delay as you mentioned and to be able to compensate for the phase error, the phase error in degrees is translated to us.

    The delay mentioned in page 24 and page29 are the measured value for precision measurement and fast settling paths of the TIDA-00777 active integrator interfaced to TIDA-00222 board. The measurement is made using the setup described in page 22, Test setup section.

    The Errors shown in the proceeding tables are after compensating for the phase error due to the hardware integrator.

    Please refer to the specification and the specs takes care of the component tolerance variation. Also most important thing to note is the phase error allowed and the components selection depends on the application. There is always a range of phase error that can be tolerated and this can be compensated in the software as we have done in TIDA-00777.

    This TI design is targeted for Breakers, Protection relays and Power measurement applications. Based on the Accuracy and startup requirement the design values can be adjusted.

    The design can be simulated using Tina-TI, SPICE-Based Analog Simulation Program for component selection( optimizing the startup and phase shift ) based on the application requirement and the same was done during the design of TIDA-00777.

     

    Thanks

    Sreenivasa