Hybrid Magnetoresistor-Planar Rogowski Current Sensing Scheme With Folded Trace Magnetic Field Concentration Technique

Wideband and isolated current measurement is required in many applications, including power electronics converters, when the switching frequency is above 1 MHz. This paper proposes a hybrid noncontact isolated current sensing scheme consisting of a magnetoresistor-based sensor and a planar Rogowski coil with complementary characteristics. In the proposed current sensing scheme, the folded trace technique is used to improve the magnetic field homogeneity in a wide frequency range, and hence the bandwidth of the sensing scheme. This paper presents the design procedures for the proposed hybrid sensing scheme. We demonstrate through experimentation that the proposed scheme yields a detection bandwidth of dc-10 MHz for 12-A current.