Integrator Design for a Small Footprint Rogowski Coil Based Current Sensor

This paper introduces a small-footprint, reset-free, analog integrator circuit for the Rogowski coil-based current measurement. Compared to alternative Rogowski coil integrator circuits, the improved integrator circuit enables a decrease of the passive capacitances of the analog integrator by four magnitudes while providing the same high-frequency transfer function response. An overview of analog integrator circuits for Rogowski coil current sensors is given. The theoretical background and design recommendations are explored. An improved, 1.89 cm² small, analog integrator circuit is designed and tested. Double pulse tests are carried out at 600 V and a drain current of 50 A. The experimental results show an accurate transient current measurement of a SiC MOSFET-based half-bridge switch current.