Analytical and Numerical Analyses of a Current Sensor Using Non Linear Effects in a Flexible Magnetic Transducer

Abstract

Abstract-A theoretical study and a simulation method are proposed for superparamagnetic current sensors implementing a uniformly wound toroidal core topology. So as to be easy to implement, this sensor topology can be made flexible thanks to the use of a core made up of a superparamagnetic powder embedded in a flexible plastic matrix. The measurement of DC and AC currents is possible provided that a sinusoidal magnetic field excitation is applied to the superparamagnetic transducer. An analytical model is proposed for computing the sensor output signal and we demonstrate that when the detection of the component at the second order harmonic of the excitation frequency is used, the measurement is independent of the conductor position in a given current range. For simulating the dynamic response of the sensor, we propose to combine the analytical model, or a finite elements model, with a time-discretization method. Furthermore, simulations are carried out considering a ring shaped sensor and the real magnetization characteristics of a superparamagnetic material. Simulations are provided over the [−10 kA 10 kA] range and for various amplitudes of the excitation signal. The results obtained with the analytical model, which is computationally efficient, are within 4% to 12.7% from the numerical results.

Neel Effect Toroidal Current Sensor

“…The total EMF sensed at the middle point of the windings connected in series is (4) e 1 (t) and e 2 (t) both feature a component at  ex and a component at 2 ex . Since  r (H) is an even and an odd function [7], given the sensed magnetic field components directions (Fig. 1), the components of e 1 (t) and -e 2 (t) at  ex cancel each other out.…”

“…An analytical model can be derived for such a sensor [7]. Consider that the latter sensor is submitted to both a H m magnetic field to measure and a sinusoidal excitation magnetic field (which can be, for example, induced by a sinusoidal current feeding an excitation winding superposed to the measurement winding) both normal to the turn cross section and homogeneous over the cross section area.…”

“…Since is an even function, the determination of H m from the measurement of the first harmonic of the EMF would lead to an ambiguity on the sign of H m . Conversely is an odd function that is monotonous over a large magnetic field range [7]. Consequently within this range, it is possible to determine H m without a sign ambiguity from the measurement of the second harmonic component of the EMF.…”

“…Thus, an electromotive force (EMF) appears at the output of the sensor. It has been demonstrated [7] that given the non linearity of the magnetic characteristic of the transducer the amplitude of the component of the EMF at the second order harmonic of the excitation frequency is an odd function of the current to measure. As this function is monotonous over a large magnetic field range the measurement of currents over ranges in the order of tens to thousands of Amperes can be envisaged, depending of the magnetization characteristic of the transducer.…”

Interplay between out-of-plane magnetic plasmon and lattice resonance for modified resonance lineshape and near-field enhancement in double nanoparticles array

“…As a result, the gaps between neighboring NPs become hot spots of electric field and magnetic field, simultaneously, at two resonance wavelengths. Different from pervious reports of achieving magnetic field enhancement through "stacked" rod pairs or disk pairs [15,29,30] , the planar DNPs enable to provide "open" cavities for the excitation and detection of magnetic transitions in atoms and molecules, showing the potential applications of magnetic nonlinearity and magnetic sensor [17][18][19] .…”