Study on L-Shaped Energy Harvester Using Magnetostrictive Material

Abstract

We investigate a L-shaped vibrational energy harvesting device using magnetostrictive material (Galfenol) for high output generation and efficiency. Galfenol is ductile magnetostrictive material with large inverse magnetostrictive effect. The device features higher output and efficiency compared with our conventional type. The device is a pair of L-shaped parallel beams consisting of Galfenol plate wound coil and stainless yoke and bias magnet. When a bending force is applied at the tip of the beam, bending moment is exerted on the Galfenol plate which yields uniform axial stress inside plate. Due to the inverse magnetostrictive effect, this stress causes flux change which time variation generates voltage on the wound coils. Prototype was verified maximum instantaneous power of 11.4W and maximum power of 0.1 J at a free vibration of frequency of 60 Hz. The output energy was increased from 20 to 30% compared with conventional type. The energy conversion efficiency more than 30% was observed.