A wind-direction adaptive piezoelectric energy harvester employing small wing passive control configuration

In this study, we propose a wind-direction adaptive piezoelectric energy harvester employing a small wing passive control configuration (WDEH-SW) for bidirectional wind energy harvesting. Our design significantly enhances bidirectional wind energy harvesting capabilities, addressing the limitations of traditional wind energy harvesters by modifying the aerodynamic characteristics of the bluff body via small wing rotations. Additionally, we introduce a criterion for determining the impact of wind direction changes on energy harvesting efficiency. Experimental comparisons with conventional galloping-based and vortex-induced vibration-based piezoelectric wind energy harvesters demonstrate the superior performance of the proposed structure. The experiment results indicate that the proposed structure effectively adapts to changes in wind direction, thereby preventing significant decrease or failure in energy harvesting efficiency. Compared to the conventional unidirectional galloping-based wind energy harvester, the proposed structure exhibits a 34.6% increase in 1.63 μW in power output, with an overall average output power reaching 6.35 μW. Notably, the proposed WDEH-SW shows an excellent wind direction adaptability and high output performance in both medium and low wind velocity ranges, providing valuable insights for designing compact bidirectional energy harvesters. This study showcases promising applications in self-powered micro-devices, particularly in straightforward bidirectional wind environments such as car or train tunnel entrances and exits.