Design and experimental analysis of a piezoelectric energy harvester based on stacked piezoceramic for nonharmonic excitations

In this study, we propose a stacked piezoceramic piezoelectric energy harvester based on inertial force excitation (SP-PEH-IFE) to efficiently harvest nonharmonic excitations. Firstly, the SP-PEH-IFE is theoretically modeled and the stacked piezoceramic is fabricated and tested. Then, impedance matching analysis is conducted in order to determine the optimal value and the energy output is calculated. Subsequently, an experimental setup is established to evaluate the proposed SP-PEH-IFE under both harmonic and nonharmonic excitations. The error between the experimental and numerical output power is less than 14.3% for a base acceleration amplitude of 10 g, demonstrating the accuracy of the SP-PEH-IFE model. Additionally, the effective output power density of the stacked piezoceramic when charging a lithium-ion battery, reached as high as 3.04 mW/cm³ at a nonharmonic base acceleration amplitude of 8 g. It is possible to further improve the output power by using a higher level of excitation or by integrating the harvester with the base structure. As a result of its broadband and high power density characteristics, the SP-PEH-IFE is capable of working in frequency varying and high acceleration conditions to power low energy consumption devices, such as railway transportation monitoring systems, and to reduce the cost of replacing chemical batteries.