Abstract: In order to improve the energy transferring efficiency and the operating frequency bandwidth, focusing on a type of broadband piezoelectric cantilever vibration energy harvester (B-PCVEH) with an elastic magnifier (EM), an improved lumped parameter coupled electromechanical model of the B-PCVEH is proposed. The model equivalent parameters are determined though the energy conversion principle and the curve fitting method by considering a correction factor and the shape information of the cantilever, and then the governing equations of motion, the frequency function and the electrical output power of B-PCVEH are derived according to the mechanics and electronics equilibrium principles. The effects of the structural parameters (such as mass ratio, stiffness ration, and damping ratio and load resistance) on the frequency performance, the vibration performance and the electric output performance of the B-PCVEH are researched by numerical simulations. The prototype of the B-PCVEH and the experiment setup are developed, and the accuracy of the output performance in the numerical solutions is identified from the experimental results. A reasonable agreement is found between the numerical results and the experimental results. The results show that larger mass and stiffness ratios and smaller damping ratio of the EM and the cantilever piezoelectric beam are helpful to improve the energy transferring efficiency and the frequency bandwidth of the B-PCVEH.

Key words: broadband, elastic magnifier, electromechanical model, experiment analysis, piezoelectric energy harvester