Interference rejection algorithm for current measurement using magnetic sensor arrays

Abstract Solid state magnetic sensors can measure a current by sensing the field near the conductor. Means are required to distinguish between useful and interference fields and that are those of conductors near the current under measurement and environmental fields. Starting from analytical expressions of the magnetic field, spatial harmonic analysis is performed. It is then possible to separate the effects of the field generated by the current under measurement from those of interference fields. A new algorithm based on spatial Discrete Fourier Transform (DFT) capable of calculating the current to be measured is presented. The algorithm can be implemented by a DSP that processes output signals of solid state magnetic sensors forming a circular array centred in the current conductor.