High-precision determination of the electrical currents and signals are in many industrial facilities and measurement systems necessary. This should be realized also mostly "contactless", that means without galvanic bonding. Soft magnetizable toroidal cores with a so-called primary and a secondary winding are generally used. The current Ip to be measured flows into the electrical conductor routed through the toroid. Thus the conductor represents the primary winding with the number of turns equal to one. The secondary circuit, usually with a high number of turns, is then subjected to an alternating voltage which influences the magnetization of the toroidal core with a defined period and amplitude. If a current Ip flows through the primary circuit or rather through the electrical conductor, the magnetization of the toroidal core is changed. In the current sensors, the change of magnetization of the toroidal core by the primary current Ip is used as a measure for determining the electric current Ip to be measured.
For the concepts without compensation and with compensation, the terms "open-looped" respectively "closed-looped" are known. In the compensation principle, the disturbing influences, such as the influence of the ambient temperature and the external magnetic fields are to be compensated. For this reason, at least a second coil turn becomes necessary. Consequently, the measurement accuracy of the compensation current sensors increases, but their production costs increase too.
The aim of the project SICOCS is developing a current sensor that has the two advantages of the concepts with and without compensation without their disadvantages. The sensor should include only one coil winding, while the compensation is ensured by a special method.