Multi-frequency electromagnetic energy harvester using a magnetic spring cantilever

In this study, an array of four generators is designed and fabricated to demonstrate the possibility of harvesting energy from different environmental frequencies. The magnetic spring technique is used as a cantilever to scavenge energy from low frequency vibrations. Initially, a single frequency energy harvester is optimized in terms of the number of turns, coil width, and coil position. Finally, two configurations of a multi-generator are fabricated. In model A, four individual generators are placed side by side; whereas in model B, the generators are placed one above the other. The experimental results show that both models can operate in the 7–10 Hz frequency range. The power densities of model A and model B are 21.92 μW/cm3 and 52.02 μW/cm3, respectively, at an acceleration of 0.5 g.