Busbar Current Transducer With Suppression of External Fields and Gradients

Yokeless busbar current transducers with circular sensor array achieve high precision when replacing Hall sensors by microfluxgate. Limited field range of fluxgate can be compensated by inverse design with sensors inside the busbar. In this paper, we present a novel scheme how to improve the immunity of such sensor against external field and field gradient. We also examine crosstalk error for external currents close to the transducer. Using five microfluxgate sensors, we designed a 400 A current transducer which has a suppression of 93 000 for currents in 40 cm vicinity.