A self-powered high sensitive sensor for AC electric current

Abstract

This paper presents a novel sensor for alternating current. The new current sensor is comprised of a ferromagnetic invariant elastic alloy (FCEA) cantilever and piezoelectric ceramic Pb(Zr,Ti)O3 (PZT8) bonded on the cantilever's root. When placed near a single electric cable carrying alternating current, the cantilever bends in the non-uniform magnetic field of the electric cable as a result of the magnetostriction of the FECA. The PZT8 produces a voltage proportional to the current in the electric cable. To produce optimal output, a tunable wolfram mass is mounted on the free end of the cantilever to make the sensor resonate with the frequency of the alternating current. This design requires no external power source and remains electrically isolated from the electric cable. Our experimental results show linear behavior with sensitivities about 211.8mV/A from 1Arms to 10Arms at a resonance frequency of 50Hz.