Fluxgate current sensor without equal core saturation in both directions?

[waveboy]

Hi,
What if the schem on fig3, page 3 (of the below) is done without the compensation error amplifier , U2?

Fluxgate current sensor:

http://www.cpdee.ufmg.br/~troliveira/docs/papers/Induscon_2018.pdf

This article was sent to us by our Chinese associates, who are offering us ferrite nanocrystalline cores so we can do this.
The article , and its predecessor, has been known to me, and mutiple of my previous companies, for the past 15 years, and the article , and its predecessor, has been freely available on the web for >15 years.

 

[FacEngrPE]

I can see needing one of these DC leakage current sensors where the electric code requires the use of Ground Fault Circuit Interrupter (GFCI), Equipment Leakage Circuit Interrupter (ELCI) or Residual Current Device (RCD).
I do not see very many situations where low voltage distribution would be advantageous in situations where the electric code or OSHA requires the use of these protection devices.
I am surprised to find that searching for DC RCD finds several commercial products.
The links found point out some classes of equipment (not explicitly code or OSHA requirements) that need RCD's internally for equipment protection (like car chargers).