A Slice-Type Magnetoelectric Laminated Current Sensor

This paper describes the design and the implementation of a new structure for an ac current sensor based on a magnetoelectric laminated composite slice. Two layers of longitudinally magnetized magnetostrictive material Terfenol-D (Tb_0.3Dy_0.7Fe_1.92) and one layer of transversely polarized piezoelectric material Pb(Zr,Ti)O₃ (PZT) were epoxy-bonded and the wire conducting the current coiled along the slice and the output voltage obtained across the two surfaces of the PZT. Compared with the reported ring-type or close-magnetic-circuit-type magnetostrictive current sensor topologies, there was no requirement for any interruption of the power supply to enable the installation and the maintenance of the sensor, which was very convenient and practical. The dimensions of the slice sensor were 30 mm × 8 mm × 2.8 mm. An averaging method was used to perform the theoretical analysis and the simulation is carried out using the COMSOL multiphysics software. The analysis, simulation, and experimental results were compared thoroughly. The current sensitivity was 1.03 mV/mA over input currents ranging from 15 mA to 2.1 A. A stable output voltage over a frequency range from 20 Hz to 5 kHz was attained by the slice. Further research on the influence of the dc bias magnetic field and the number of turns of the current coil on the output characteristics of the sensor has been carried out. This current sensor has great potential for further research and applications.