Design of a multi-stable piezoelectric energy harvester with programmable equilibrium point configurations

Abstract

In this paper, a novel multiple-stable piezoelectric energy harvester with programmable equilibrium point configurations is proposed. Currently, multi-stable energy harvesters have been widely investigated due to possible improvement in performance. However, there are two main problems in the existing literature. The first is that obtaining multiple stable equilibrium points for energy harvesters, such as penta-stable, hepta-stable points, requires a highly complex structural design. The second is that the current design is difficult to arbitrarily specify the number and the coordinates of the equilibrium points, which is helpful for optimizing the performance of the energy harvester. Therefore, we solve these two problems by using programmable nonlinear force technology. As examples, a tri-stable and a hepta-stable energy harvester with specified coordinates of equilibrium points are designed. Both simulations and experiments show that the designs are feasible. Under the acceleration of 2 m/s2 at 7 Hz, the tri-stable energy harvester can charge a 4.7 μF capacitor to 28.6 V, and the hepta-stable energy harvester can charge the capacitor to 21.9 V in 40 s. These voltages are sufficient to power some sensor nodes. In a word, the proposed method is promising in the performance optimization of energy harvesters.