Research on Low-Frequency Multi-Directional Piezoelectric Energy Harvester with Combined Cantilever Beam

In order to realize the collection and utilization of low-frequency vibration energy, a multi-directional piezoelectric energy harvester is proposed, which consists of a lower circular arc beam and an upper L-shaped beam. Both the lower and upper beams can achieve multi-directional energy harvesting, and the upper L-shaped beam can also act as a mass block to reduce the resonant frequency. The structure of this energy harvester is optimized. Four different structures are studied with varying combination angles between the upper and lower layers to acquire data related to resonant frequency, vibration shape, stress distribution, open-circuit voltage, and output power. Additionally, the performance of each structure is comprehensively prepared and measured to verify its effectiveness. The optimal structure achieved a resonant frequency of 11 Hz and an output power of 57.1 μW at the optimal load resistance of 201 kΩ. Consequently, this work provides valuable reference for the study of low-frequency vibration energy harvesting technology.