A Low-Cost Current Sensor Based on Semi-Cylindrical Magnetostrictive Composite

Abstract

This paper presents the design, fabrication, and characterization of a compact current sensor based on magnetostrictive composites and resistance strain gauges. Firstly, we designed three kinds of current sensors with different structures, in which the shape of the giant magnetostrictive material (GMM) was cuboid, cylindrical, and semi-cylindrical. A set of finite element method (FEM) simulations were performed to qualitatively guide the design of three prototypes of the current sensor. It was determined that the most ideal shape of the GMM was semi-cylindrical. Secondly, Terfenol-D (TD) powder and epoxy resin were mixed to prepare magnetostrictive composites. In this paper, magnetostrictive composites with different particle size ranges and mass ratio were prepared and tested. The results show that the magnetostrictive composites had the best performance when the particle size range was 149–500 μm and the mass ratio of epoxy resin to TD powder was 1:5. Finally, this paper tested the performance of the sensor. The sensitivity, repeatability, and linear working range of the sensor reached 0.104 με/A, 2.51%, and 100–900 A respectively, when only 0.31 g of TD powder was employed. This means that current measurement with low cost, high sensitivity, and wide range was realized.