Simulation Study on Core Material of Weak DC Current Sensor

Abstract

ZnMn ferrite, cold-rolled silicon steel, permalloy and nanocrystalline alloy can be used as magnetic cores of current sensors. And based on these four materials’ inherent characters of electromagnetic, this paper presents closed loop simulation model of them using Ansoft which is a finite element analysis software. In simulation, the measuring currents are set to DC currents ranging from 0 to 1mA. And different amplitudes of variation of currents are set for each material. The simulation of each material produces 280 sets of data and with these data a series of curves of magnetic field changing with currents can be plotted using Matlab. The simulation results show that permalloy and nanocrystalline alloy have good characters of electromagnetic and they are suitable for detecting weak DC currents. When these two materials are used as magnetic cores of sensors, the theoretical detecting accuracy can be up to 0.001mA, meanwhile, detecting accuracy of ZnMn ferrite is about 0.1mA to 0.01 mA.