• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 47 subscribers
  • Views 1642 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.

OPA2188: Rogowski Coil Interfacing for Current for Closed Loop Feedback

Karan123
Intellectual 510 points

Part Number: OPA2188
Other Parts Discussed in Thread: ADS131A02, TIDA-00777, OPA188, OPA2192

Hi,

I have to update PWM Duty Cycle w.r.t for Current measurement from Rogowski Coil to achieve constant current of welding machine(s)  ?

What is the best way for Interfacing Rogowski Coil for Current measurement for High Speed Closed Loop Feedback System ( Not For Energy/Current Measurement after 50Hz or 60Hz) 

for Interfacing with 12-bit ADC ?

I have go through following part:

1)

I  have seen , OPA2188

http://www.ti.com/tool/TIDA-00777

2) ADS131A02

https://www.ti.com/lit/ds/symlink/ads131a04.pdf?ts=1591633466135&ref_url=https://

Is there way to do simulation of Rogowski Coil  ?

Please advice..

Thanks in advance..

--

Karan123

  • 0
    TI__Guru* 93105 points

    Hello Karan,

    From a Precision Amplifiers standpoint TIDA-00777 is our most complete resource for interfacing the Rogowski coil in a signal chain. In section 4.2.1 it highlights what op amp characteristics are important for the application:

    4.2.1 OPA2188/OPA188

    An op amp is used at each stage of precision measurement and fast settling. Selecting an op amp is critical for the design.

    Key specifications for selecting an op amp for an integrator design include:

    • Low offset and offset drift helps in minimizing calibration as well as degradation in performance over temperature.

    • Low bias current helps in minimizing the loading of the Rogowski coil, thereby reducing gain error.

    • Low voltage noise density improves repeatability and accuracy at low input currents of the Rogowski coil. The OPA2188 dual op amp is used in this design for integrator and gain stage. The OPA188 single op amp is used in this design for the DC level shift stage and to buffer voltage reference.

    The OPA2188 zero drift op amps are certainly useable for this application. However, there are now newer e-trim op amps such as the OPA2192 that you may want to consider. It provides even lower input voltage noise than the OPA2188.

    We don't cover the A-to-D products here on the Precision Amplifiers e2e forum so you would need to post any questions about using the ADS131A02 for this type of application the Converter products e2e forum.

    I do not know of a Rogowski coil simulation model. I suggest you post that question to the TI Sensing products e2e forum. They focus on applications using Rogowski coils and may have a model they use.

    Regards, Thomas

    Precision Amplifiers Applications Engineering