Design of a high-performance piecewise bi-stable piezoelectric energy harvester

At present, for the widely used Duffing-type bi-stable energy harvesters (D-BEH) with smooth nonlinear forces, there is a trade-off between large equilibrium point coordinates and small potential energy differences. In this study, programmable nonlinear force technologies are used to customize a piecewise bi-stable nonlinear force. Then, a novel piecewise bi-stable energy harvester (P-BEH) is designed to solve this trade-off. The results show that when the coordinate of the equilibrium point is 10 mm, the potential difference of the P-BEH is only 0.05 mJ, while that of the D-BEH is as high as 0.37 mJ. Therefore, the P-BEH can easily overcome the potential difference to make inter-well vibration at the excitation level of 2 m/s², while the D-BEH can only perform intra-well vibration. Compared with the D-BEH, the P-BEH results in a 46% increase in the peak power and a 767% increase in the bandwidth. Simulation and experiment show that the proposed P-BEH has small potential differences and large equilibrium point coordinates, making it have better energy harvesting performance than the D-BEH.