Calculation of fluxgate sensor parameters

In this work, we present two ring-core fluxgate sensor designs to investigate the accuracy of parameter calculations such as inductance and resistance of the windings, demagnetization factor and apparent permeability. All these parameters as well as relative permeability are measured and some simulations are performed through a FEM (Finite Element Method) analysis tool. Measurement results are compared with the calculated theoretical values in addition to FEM analysis results. In the first design, a crystalline core stacked from circular permalloy laminations is used while an amorphous core wound from Vitrovac 6025Z strip is preferred for the second design. Demagnetization factors are calculated by using well-known empirical and analytical formulas in the literature. The results point out that a new demagnetization factor formula is necessary because the three formulas used miscalculate for the designed sensors. Moreover, calculating the demagnetization factor by using finite element analysis method is found to be reliable.