Dual-source energy harvester for collecting both flow-induced and multi-directional vibratory energies

Inherent ambient energy sources manifest in diverse forms, including wind and vibrations. Currently, significant attention has been directed toward enhancing energy conversion efficiency from individual sources. However, there has been limited exploration of multi-source energy harvesting systems in recent studies. This research proposes a novel dual-source vibration energy harvester (DVEH) that employs a spherical pendulum to capture both flow-induced and multi-directional vibration energies. The proposed structure integrates a specialized bluff body with a square section attached to the end of a piezoelectric beam. Within the bluff body, a spherical pendulum exploits nonlinear coupling between the beam’s bending vibration and pendulum motion. Additionally, the bluff body captures wind energy through the galloping effect. To assess the energy harvesting performance, we formulate a theoretical model. Experimental validation is conducted to corroborate our theoretical findings. The maximum output power attains 0.55 mW at a wind speed of 5 m/s. Furthermore, for multi-directional vibration energy harvesting, the output root mean square (RMS) piezoelectric voltage attains 1.28 V, 3.13 V, and 2.67 V (The corresponding directions are along the beam length direction, along the beam vibration direction and along the beam width direction), respectively. In summary, the outcomes reveal commendable dual-source vibration energy harvesting capabilities in the proposed structure.