A novel frequency tuning design for vibration-driven electromagnetic energy harvester

The common vibration energy harvester effectively converts vibration energy to electricity when an ambient frequency matches the resonant frequency of the device. In this study, we proposed a novel frequency tuning design of vibrationdriven energy harvester, which used electromagnetic conversion. The proposed frequency tuning method uses a rotatable spring in order to adjust the spring constant. The proposed tuning-based energy harvester has been successfully tuned to have a resonant frequency from 23 to 32 Hz. The experimental results demonstrated that the proposed energy harvester can generate a maximum power output of 60 μW with an acceleration of 0.5 g.