Crosstalk analysis and Current Measurement Correction in Circular 3D Magnetic Sensors Arrays

Abstract

The circular array of magnetic sensors is a research hotspot in the field of power electronics, especially for the measurement of direct current(DC). The high linearity, large dynamic range, small size and low power consumption of circular magnetic sensors arrays for current measurement are an improvement over the current sensors utilizing a ferromagnetic core. However, due to the absence of core magnetization, the external magnetic field can easily enter the magnetic sensors, which will affect the measurement accuracy. Therefore, this paper focuses on the influence of the interference field from the conductor positioned outside the circular array and proposes a model of the target conductor penetrating the circular array with the interference conductor outside the circular array. This model is used to analyze the influence of relevant parameters of the interference conductor and the target conductor on the crosstalk error. An interference-rejecting method of circular 3D magnetic sensor arrays is proposed, which establishes the model of magnetic flux density measurement to calculate the target conductor current. The simulation results show theoretically that the method can greatly reduce the crosstalk error and correct current measurement. 3-D tunnel magnetoresistance (TMR) chip is selected as the magnetic sensors of the circular array in the laboratory experiment, and the experiment errors can be reduced to around 1%. The simulation and experiment results verify that the interference-rejecting method can correct measurement results and improve the accuracy of the target current.