A Wideband Nonlinear Bistable Piezoelectric Energy Harvester with Variable Potential Well

Vibrations within various natural and artificial surroundings are ubiquitous which promotes the increasing interests in vibration energy harvesting research. Compared with the linear energy harvester, the nonlinear system can effectively broaden the bandwidth. This paper presents a wideband nonlinear beam-spring piezoelectric energy harvester. The design consists of a piezoelectric cantilever beam with a tip magnet and an interacting magnet mounted on a rotatable bar with a torsional spring. The interaction between two magnets forms a bistable potential energy function. The shape of the potential well could change with the rotation of the bar, facilitating the occurrence of the snap-through motion under low amplitude and wideband vibration excitation. The theoretical model of the designed energy harvester is derived based on the Hamilton principle. The dynamical responses with bistability are evaluated by numerical simulations and verified by experiments. The results show that the proposed piezoelectric energy harvester is capable of harvesting low frequency wideband vibration energy.