MAGNETOSTRICTIVE-PIEZOELECTRIC COMPOSITE STRUCTURE FOR ENERGY HARVESTING

Harvesters coupling magnetostrictive and piezoelectric materials are investigated. The energy conversion from slow magnetic field variations to electricity is detailed. Experimental results are exposed for two macroscopic demonstrators based on the translation and rotation of a permanent magnet, using a choice of piezoelectric (fiber composite and bulk PZT) and magnetostrictive (amorphous FeSiB ribbon and bulk Terfenol) materials. Quasi-static (sub-Hz) harvesting is achieved with exploitable output voltages. Integrated microharvesters using sub-micron multilayers of active materials have been built and are currently being characterized.