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In this article, a broadband magnet-induced dual-cantilever piezoelectric energy harvester is designed and developed. The dual-cantilever structure consists of an outer and an inner beams with magnets attached to the tips. The magnets generate nonlinear repulsive force between the two beams and make the structure bistable. In the theoretical model, each beam is considered as a single-degree-of-freedom system with magnetic force applied at the free end. From the simulation results, chaotic motion is observed in a wide frequency range. A prototype of the harvester is built and verified with the simulation results. The simulation and experimental results show good agreement with respect to the power bandwidth and amplitude. The distance between magnets is adjusted to observe its effect on the power response of the harvester. The inner and outer beams are simulated and tested independently first to observe the performance of each beam. Finally, an interface circuit is designed to combine all piezoelectric plates to acquire the overall performance. By comparing with the traditional piezoelectric energy harvester, the new design is shown to provide a significant improvement in bandwidth.

This paper presents a tri-directional piezoelectric energy harvester that is able to harvest vibration energy over a wide bandwidth from three orthogonal directions. The harvester consists of a main beam, an auxiliary beam, and a spring-mass system, with magnets integrated to introduce nonlinear force and couple the three sub-systems. Theoretical analysis and experiments were performed at constant acceleration under frequency sweeps to acquire frequency responses. The experimental results show that the voltage can achieve more than 2 V over more than 5 Hz of bandwidth with 1 MΩ load in the three orthogonal directions.

This paper investigates the design and analysis of a broadband piezoelectric energy harvester that uses a simply supported piezoelectric beam compressed by dynamic loading. The beam is restrained at one end and carries a moving mass at the other end where a magnetic force is applied axially. Taking advantage of the flexibility of the slender beam and the nonlinearity of the magnetic force, the design aims to enhance the harvester’s functionality with a broad frequency bandwidth. Both theoretical and experimental investigations are performed in this study over a range of excitation frequencies. Specifically, the electromechanical model of the harvester is analytically developed by means of the energy-based method and the extended Hamilton’s principle. Using the derived model, a parametric study is carried out to obtain the harvester’s voltage response under parametric excitations. Furthermore, the effects of various parameters on the harvester’s voltage response are examined. A prototype harvester is fabricated and experimentally tested. The theoretical model is validated against experimental data to confirm the harvester’s nonlinear response behaviors and enhanced capabilities. Both simulation and experiment illustrate that the harvester exhibits a softening nonlinearity and hence a broad frequency bandwidth with large-amplitude voltage response. It is also shown from numerical simulations that the harvester’s performance can be further improved by properly selecting the end mass and reducing the mechanical damping. The present findings demonstrate that dynamic compressive loadings can be successfully utilized to increase the harvester’s voltage output and frequency bandwidth.