Research on Multi-DirectionalPiezoelectric-Electromagnetic CompositeVibration Energy Harvesters

Abstract Vibration energy harvesting technology plays a crucial role in converting minuscule vibrational energy into stored electrical energy, holding significant research importance. To address the collection of low-frequency vibration energy from various directions, this paper introduces a piezoelectric-electromagnetic hybrid vibration energy harvester capable of multi-directional energy collection. The piezoelectric component of this harvester employs a structure coupling a resonant beam and a cantilever beam at a 90-degree angle, enabling the collection of vibration energy in any direction within a two-dimensional plane. The electromagnetic part utilizes a tile-shaped permanent magnet to ensure adequate cutting of magnetic flux lines by the relative motion between the magnet and the coil. This paper establishes a dimensionless parameter model and derives a normalized power output expression. Through simulation analysis using Ansys and Comsol, the harvester's structure parameters are optimized. Additionally, based on this analysis, a physical model is fabricated, and comprehensive experiments and analyses are conducted. The results indicate that the maximum power outputs of the piezoelectric and electromagnetic components are 5.91mW and 3.12mW, respectively. For excitation in different directions within a two-dimensional plane, the harvester consistently achieves a maximum root mean square voltage exceeding 5V in the 10-25Hz frequency band, demonstrating excellent multi-directional harvesting performance.