Design, modeling and experiments of broadband tristable galloping piezoelectric energy harvester

Galloping based piezoelectric energy harvester is a kind of micro-environmental energy harvesting device based on flow-induced vibrations. A novel tristable galloping-based piezoelectric energy harvester is constructed by introducing a nonlinear magnetic force on the traditional galloping-based piezoelectric energy harvester. Based on Euler–Bernoulli beam theory and Kirchhoff’s law, the corresponding aero-electromechanical model is proposed and validated by a series of wind tunnel experiments. The parametric study is performed to analyse the response of the tristable galloping-based piezoelectric energy harvester. Numerical results show that comparing with the galloping-based piezoelectric energy harvester, the mechanism of the tristable galloping-based piezoelectric energy harvester is more complex. With the increase of a wind speed, the vibration of the bluff body passes through three branches: intra-well oscillations, chaotic oscillations, and inter-well oscillations. The threshold wind speed of the presented harvester for efficiently harvesting energy is 1.0 m/s, which is decreased by 33% compared with the galloping-based piezoelectric energy harvester. The maximum output power of the presented harvester is 0.73 mW at 7.0 m/s wind speed, which is increased by 35.3%. Compared with the traditional galloping-based piezoelectric energy harvester, the presented tristable galloping-based piezoelectric energy harvester has a better energy harvesting performance from flow-induced vibrations.