Design of a vibration energy harvester by twin lateral magnetoelectric transducers

Scavenging energy from vibration is important for several fields of science and technology. A big challenge thereby is to realize miniaturized solutions able to deliver sufficient energy for supply a wireless sensor node. A magnetoelectric (ME) vibration energy harvester based on a twin laminate composite of magnetostrictive and piezoelectric materials was designed, developed and tested. The vibration converter uses simultaneously two transversely polarized PZT plates and two longitudinally magnetized Terfenol-D plates placed within a magnetic field. The presented design can make the best use of the magnetic field produced by the magnetic circuit. The repulsion force is generated by two magnetic springs leading to less friction than a classical mechanical spring. The implementation issues of the harvester have been subjected to several experimental studies using an adjustable artificial excitation source. The results show that doubling the amplitude of vibration leads to an energy output which is four times more. The comparison with a single transducer shows that the twin lateral converter reaches especially at resonance frequency the one and half energy outcome.