AC current-to-voltage transducer based on digital processing of Rogowski coils signal

Abstract

Rogowski coils represent an attractive solution for AC current measurement, since they feature a wide bandwidth, high degree of galvanic insulation, and low cost compared to traditional measuring system like shunts and current transformers. The drawback in their use is represented by the need for integrating the EMF picked up at their terminals. The integration of the EMF signal is classically obtained by an analog integrator. problems related to the availability of suitable electronic integrator circuits usually limit the use of the Rogowski coil in the field of very large currents and/or very fast electrical transients. In a recent work, the authors developed a new integration process of the EMF signal induced in the coil, using digital signal processing. Since this approach was based on a data acquisition board and a PC, it was not suitable for industrial application. For this reason, we propose a novel and improved integration process, still based on a simple digital signal processing but implemented now in a stand alone board. The new system is characterized by accuracy and stability levels of the output signal well suitable for the majority of industrial applications, especially when low-amplitude and low-frequency current measurements are considered.