Ring-type electric current sensor based on ring-shaped magnetoelectric laminate of epoxy-bonded Tb₀.₃Dy₀.₇Fe₁.₉₂ short-fiber/NdFeB magnet magnetostrictive composite and Pb(Zr, Ti)O₃ piezoelectric ceramic

Abstract

A ring-type electric current sensor operated in vortex magnetic field detection mode is developed based on a ring-shaped magnetoelectric laminate of an axially polarized Pb(Zr, Ti)O₃ (PZT) piezoelectric ceramic ring bonded between two circumferentially magnetized epoxy-bonded Tb₀.₃Dy₀.₇Fe₁.₉₂ (Terfenol-D) short-fiber/NdFeB magnet magnetostrictive composite rings. The electric current sensitivity of the sensor was evaluated, both theoretically and experimentally. The sensor showed a high nonresonance sensitivity of ∼12.6 mV/A over a flat frequency range of 1 Hz–30 kHz and a large resonance sensitivity of 92.2 mV/A at the fundamental shape resonance of 67 kHz, besides an excellent linear relationship between the input electric current and the output magnetoelectrically induced voltage. The power-free, bias-free, high-sensitive, and wide-bandwidth natures of the sensor make it great potential for real-time condition monitoring of engineering systems having electric current-carrying cables or conductors.