A magnetostrictive/piezoelectric laminate transducer based vibration energy harvester with resonance frequency tunability

This paper presents a resonance frequency tunable vibration energy harvester based on magnetoelectric (ME) transducer. The harvester is composed of a ME transducer, a cantilever beam, a cylindrical magnet and a circular magnet. The cylindrical magnet is fixed on the free end of the beam. The ME transducer is placed in the hole of the circular magnet that can produce an optimized bias magnetic field through the transducer, which results in an improved ME voltage coefficient. During vibration, the cylindrical magnet moves relative to the transducer which generates electrical power due to the magnetic field variation. The resonant frequency of the harvester can be tunable by taking advantage of the repulsive magnetic force between the magnets. A prototype is fabricated and tested. A resonant frequency tunable range of 4.4Hz is achieved and the maximum power generated is 68.8μW under an acceleration of 0.2g at a resonant frequency of 25.4Hz.