Optical Fiber Current Sensors Based on FBG and Magnetostrictive Composite Materials

Abstract

Optical fiber current sensors are widely used in the online monitoring of a new generation power system because of their high electrical insulation, wide dynamic range, and strong anti-electromagnetic interference ability. Current sensors, based on fiber Bragg grating (FBG) and giant magnetostrictive material, have the advantages of high reliability of FBG and high magnetostrictive coefficient of giant magnetostrictive material, which can meet the monitoring requirements of digital power systems. However, giant magnetostrictive materials are expensive, fragile, and difficult to mold, so giant magnetostrictive composite materials have replaced giant magnetostrictive materials as the sensitive elements of sensors. High sensitivity, high precision, wide working range, low response time, and low-cost optical fiber current sensors based on magnetostrictive composites have become a research hotspot. In this paper, the working principle of the sensor, the structure of the sensor, and the improvement of magnetostrictive composite materials are mainly discussed. At the same time, this paper points out improvements for the sensor.

Self-Similarity in Magnetostrictive Materials: An Experimental Point of View

“…Similar behaviors are observed for magnetostrictive curves [1] and also for ferromagnetic materials [4,5]. These properties can be exploited for sensing [6,7] and for non-destructive testing [4].…”

Miniaturized FPI-FBG integrated sensor for parallel monitoring of magnetic field and magnetic fluid refractive index

“…Spontaneous lattice strain depends on the direction of the spontaneous magnetization in the lattice, and how the dependence is achieved from considerations of lattice symmetry. The FBG wavelength redshift is attributed to the strain induced to magnetostrictive coated material Using equation (27) and considering the resolution of the spectral analyzer (0.02 nm), the maximum errors of magnetic field and RI detection are obtained to be 0.016 mT and 1.69×10 −4 RIU, respectively. In this part, the effects of temperature and strain induced by magnetostrictive material on FPI part of the sensor are investigated.…”

“…The integration process of the magnetostrictive type of materials with the optical fiber, in certain cases, faces some difficulties. Moreover, due to the temperature dependence of the MF refractive index and its hysteresis time, the extensional viscosity delay time occurs [27], which makes it unavoidable to use additional schemes to compensate for the thermal influence. Despite these disadvantages, the use of MF-based magnetic field sensors is still increasing, reflecting these materials' beneficial characteristics [28].…”

“…The response of the FPI sensor to RI changes shows good linearity in the range of 1.327-1.340 and is used to calculate C n1 . Based on the analysis of the spectral wavelength shifts, presented in the form of a matrix in equation(21), and by substituting the sensitivities (coefficient) into it, the specific measurement for the cross-sensitivity can be solved by the matrix in equation(27) as follows:…”

Structural optimization of magnetostrictive composite materials in magnetostrictive current sensor

“…Therefore, in order to overcome the shortcomings of giant magnetostrictive alloy, a magnetostrictive polymer composite is proposed, which is a resin matrix composite composed of magnetostrictive alloy powder and resin. At present, a large number of scholars have also done a lot of research on improving the performance of magnetostrictive composites [18], including the magnetic domain orientation of particles in the curing process of composites [19,20], prestress [21], coupling agent [22], particle fraction [23], particle size [24]. By improving the performance of magnetostrictive composites, the performance of current sensors is further improved.…”