Design of a magnetoelectric mechanism for harvesting power-frequency magnetic field energy of power lines

Abstract

A magnetoelectric mechanism is presented for extracting power-frequency (50 Hz or 60 Hz) magnetic field energy of ambient power lines, which can provide power for wireless sensor networks. A detachable NdFeB magnet is used to produce bias magnetic field for the magnetostrictive plate. The employment of the magnetic circuit allows more powerfrequency magnetic flux pass through the magnetostrictive plate. When the power cord is energized, the magnetostrictive plate generates a shear stress which transmits to the piezoelectric plate. The piezoelectric plate deforms in shear mode and a voltage is induced. The feasibility of the presented magnetoelectric mechanism was experimentally validated using a fabricated prototype. The experiments were performed and the results show that the output open-circuit voltage depends on the separating distance d. For the current of 10 A and the separating distance d=1.5 mm, the open-circuit RMS voltage reaches 4.39 V, and a power of 14.9 μW is produced with a matching resistive load of 0.65 MΩ. The results show the potential prospect of the magnetoelectric mechanism for power-frequency magnetic field energy harvesting.