MEMS Rogowski Coil Current Sensor with Spiral Return Coil

Abstract

We have developed a MEMS Rogowski coil current sensor with spiral return coil. The Rogowski coil is formed on a silicon substrate clockwise and counterclockwise from the edges, for current detection and external magnetic noise compensation (device size 10×10×0.3 mm³, spiral coil 135 turns, via diameter 100 µm).

When the slew rate (di/dt) was kept constant at 10 A/µs, and the current was changed by 5 A up to 40 A, MEMS Rogowski coil could detect current linearly. When the slew rate was changed by 10 A/µs up to 100 A/µs, it was found that the MEMS Rogowski coil could detect current almost linearly following the reference sensor. Hence, external noise compensation by the return coil has been confirmed.