Piezoelectric energy harvesting from AC current-carrying wire

Abstract

The magnetic field surrounding an AC current-carrying wire is a promising source for energy harvesting. In this study, an AC magnetic field energy harvester is developed based on the piezoelectric vibration energy harvester. A permanent magnet placed near the AC current-carrying wire vibrates by coupling with the AC magnetic field. The kinetic energy of the vibration can be converted by the piezoelectric effect. Theoretical analysis indicates that the harvester composed of a piezoelectric cantilever with a permanent magnet at the free end should be placed so that the magnet and the wire do not collide. Then, the harvester was fabricated using a piezoelectric bimorph cantilever with a mechanical quality factor of 66 and a generalized electromechanical coupling factor (K2) of 3.1% and a neodymium magnet with a mass of 3.1 g. At an AC current of 5 Arms with a frequency of 50 Hz, an output of 1.3 mW was obtained.