The Influence of Interference Sources on a Magnetic Field-Based Current Sensor for Multiconductor Measurement

Magnetic sensor arrays have been widely regarded as the practical implementations of current transducers, due to their ability to meet the demands for low power consumption and high accuracy in a wide frequency range. However, when used to reconstruct the currents flowing in the massive parallel conductors, e.g., a three-phase system, the setup still proves to be susceptible to the effects of external magnetic fields. In an effort to improve the immunity of this method, a differential array of magnetic field sensors is investigated. In this differential approach, the Moore-Penrose inversion method (least square inversion method) is used to obtain the set of currents at different positions inside the sensor from the measurement of the radial difference of the magnetic fields. The measurements, which were conducted in this paper, show that the differential array has a reduced crosstalk error when compared with a usual single-annular array of the same size and thus shown an improved immunity to the external magnetic fields by a factor of three and better.