Energy Harvesting from Ambient Vibration at Low Force/Acceleration Input

Background: Ambient vibration is a promising source to provide low-power electronic devices with energy. The piezoelectric direct effect is widely used to generate energy from mechanical stress. Generating sufficient power in milliwatts is often obtained with input acceleration greater than 1g (9.81 m/s²) Aim: In this work, the author demonstrated that low acceleration (between 0.1g and 0.9 g) vibration sources can be utilized to generate a satisfactory level of electric power. Methods: A low pre-stress was introduced by fixing the piezo structure to the shaker using adhesive tape. The driving force was less than 0.06 N. The harvester was tested at a vibration frequency of 173 Hz. Results: The maximum power of 1.5 mW was achieved when the harvester resistance matched the load resistance value. At maximum harvested power, the efficiency was found to be 1.6. Conclusion: The results indicated that prestressed piezoceramics are a good candidate for vibration energy harvesting.