Compensation current sensor arrangement

A current sensor arrangement capable of measuring a current in a primary conductor according to the compensation principle comprising:

• a magnetic core formed from a soft magnetic material, said magnetic core magnetically coupling a primary conductor, a first secondary winding and a second secondary winding together;
• said primary conductor configured to carry a primary current to be measured by said current sensor arrangement, said primary current creating a first magnetic flux in said magnetic core;
• a magnetic field sensor configured to detect and measure a magnetic flux in said magnetic core and to generate a signal based on said measured magnetic flux;
• a first evaluation circuit electrically connected between said magnetic field sensor and said first secondary winding, said first secondary winding being wound around said magnetic core in a manner to generate a first rectifying magnetic flux in said magnetic core compared to said first magnetic flux, said first evaluation circuit configured to receive said signal from said magnetic sensor and to generate a first compensation current that is proportional to said signal with said first compensation current passing from said first evaluation circuit to said first secondary winding, thereby creating said first rectifying magnetic flux in said magnetic core with said first rectifying magnetic flux reducing a net magnetic flux in said magnetic core to nearly zero;
• a second evaluation circuit electrically connected between said first secondary winding and said second secondary winding, said second secondary winding being wound around said magnetic core in a manner to generate a second rectifying magnetic flux in said magnetic core compared to said first magnetic flux, said second evaluation circuit configured to measure said first compensation current and to generate a second compensation current that is smaller than said first compensation current and proportional to it, said second compensation current passing to said second secondary winding thereby generating said second rectifying magnetic flux, a sum of said first and said second rectifying magnetic fluxes being sufficiently large enough to reduce said net magnetic flux in said magnetic core to zero;
• and
• wherein said first secondary winding is wound around said magnetic core with a turn number that is greater than a turn number of said second secondary winding;
• said first secondary winding and said second secondary winding each having a wire diameter such that a current density in said first secondary winding is equal to a current density in said second secondary winding when said first compensation current and said second compensation flow through them;
• and said first or said second compensation current represents said primary current to be measured flowing in said primary conductor.