Influence of the Conductor Position on a Circular Array of Hall Sensors for Current Measurement

Contactless galvanically isolated magnetic field-based current sensors utilizing a ferromagnetic core have been widely used for decades in many applications such as power distribution, power electronics, and drive technologies to mention just a few fields of interest. Measurement techniques like circular arrays of magnetic-field sensors are of high interest in the field of power electronics, especially for dc current sensing. The low power consumption, high sensitivity, and mechanical flexibility of modern circular arrays of magnetic sensors for current measurement are an improvement over older closed-loop high power consumption systems. In this paper, we will theoretically and experimentally show the influence of the inner displacement of the conductor on the accuracy of the circular array of magnetic-field sensors. The calculation of the current is based on the Kelvin-Stokes theorem. The experimental results were taken with six Hall-effect sensors which are uniformly placed as a circular array. The measurements have been taken at different distances and angles to the conductor. To prove the theoretical background the currents were calculated in all cases for a number of six and three sensors.