Two-dimensional elliptically shaped electromagnetic vibration energy harvester

An elliptically shaped electromagnetic vibration energy harvester is presented for two- and one-dimensional motions with the easy tuning of resonance frequency. The consists a free-to-move ring-shaped permanent magnet radial magnetization, set cube magnets distributed in fixed holder, two coil windings located above below harvester. When device exposed to vibrations, ring moves until magnetic restoring force from pushes it back while inducing an on coils. performance characterized using XY-shaker, whose frequency swept 1 Hz 10 motion amplitudes 2 mm 4 both axes simultaneously. Unlike 1-D harvesters, resulting output power shows resonant frequencies at 4.5 7 Hz, which can generate around 1.5 mW. also displays nonlinear hardening resonator behaviour. Finally, 1D experimental results show that prototype depends its angular position respect direction source, reaching maximum 45∘.