Modeling and Experimental Characterization of a Piezoelectric Energy Harvester with a Wind Concentrator Structure

Piezoelectric wind energy harvesters have gained much attention in recent years due to their potential as renewable energy sources for wireless sensor networks. However, the low energy output limits its application in practice. In order to improve the output performance, a piezoelectric wind energy harvester with a wind concentrator structure is studied. The wind concentrator structure is used to concentrate the wind flow and improve the vibration characteristics and output performance of the harvester. An analytical model is developed to describe the interaction between the fluid and the solid. Various analytical results, such as the velocity contour and the pressure contour for the flow, displacement of the free end of the polyvinylidene fluoride (PVDF) beam, are obtained. The influences of the position parameters of the PVDF beam on the vibration displacement are analyzed. The prototype harvester was fabricated and measured experimentally. The trend of simulation results is consistent with that of measured data. When the wind speed is 14 m/s, the output voltage RMS (root mean square) of the harvester with and without the wind concentrator are 2.23 V and 1.16 V, respectively. The output voltage RMS of the former is about two times that of the latter. This experiment verifies the validity of the wind concentrator.