This paper investigates an experimental approach for enhancing the output power of a piezoelectric energy harvester. The proposed method adopts inductance to reduce the effect of the piezoelectric harvester’s impedance, and boost the output power. Four electrical circuits for a piezoelectric beam harvester are investigated experimentally; Simple Resistive Load (SRL), Inductive Load (IL), Standard AC-DC, and Inductive AC-DC circuits. The results show that the adaptation of inductor in the IL and Inductive AC-DC improves the output power compared to the SRL and Standard AC-DC respectively. The Inductive AC-DC circuit is shown to increase the output power by 6.7% in comparison to the existing standard AC-DC circuits.

This paper describes an innovative method for enhancing the power output of a piezoelectric energy harvester. The proposed approach is adopting inductance to reduce the effect of the internal capacitance of the piezoelectric harvester to boost the power output. Four electrical circuits for a piezoelectric beam harvester are studied; Simple Resistive Load (SRL), Inductive Load (IL), Standard AC-DC, and Inductive AC-DC circuits. An inductor is added to the SRL and standard AC-DC circuits to build the new IL and Inductive AC-DC circuits respectively. The power outputs of the four circuits are then studied. The results show that the adaptation of inductor enhances the power output. The IL circuit enhances the power output comparing to the SRL circuit. The Inductive AC-DC circuit also avails the standard AC-DC circuit.

This paper provides a comparison between two different energy harvesting circuits for a piezoelectric flag subjected to uniform flow. Between two circuits tested, one is Simple Resistive Load, and the other one is the standard AC-DC circuit. To experimentally investigate these circuits, the piezoelectric flag output voltage has been studied under various wind speeds in a wind tunnel. The simple resistive load circuit provides an alternating voltage, and not a DC voltage. The standard AC-DC circuit is used to convert the AC voltage into a DC voltage; however, the power dropped as a result of the voltage drop across the forward-biased diodes.

In this paper, a new method is proposed for improving a piezoelectric energy harvester’s output power. A piezoelectric vibration energy harvester has an inherent internal capacitance. The new approach adopts inductance to reduce the reactance of the internal capacitance and enhance the output power. To show the practicality of this method, four electrical circuits are investigated numerically and experimentally for a piezoelectric beam energy harvester: Simple Resistive Load, Inductive Load, standard AC-DC, and Inductive AC-DC circuits. An Inductive Load circuit is built by adding an inductor to a Simple Resistive Load circuit, while an Inductive AC-DC circuit is built by adding an inductor to a standard AC-DC circuit. Experimental results indicate that the Inductive Load and the Inductive AC-DC circuits avail the Simple Resistive Load and standard AC-DC circuits respectively. The inductive AC-DC circuit shows a 6.7% increase in the output power compared to the standard AC-DC circuit.

This paper aims to investigate the free coupled flexural-torsional vibrations of a double cantilever structure. The structure consists of two identical Euler-Bernoulli cantilever beams with a piezoelectric layer on top. The beams are connected by a rigid tip connection at their free ends. The double cantilever structure in this study vibrates in two distinct modes: flexural mode or coupled flexural-torsional mode. The flexural mode refers to the in-phase flexural vibrations of the two cantilever beams resulting in translation of the tip connection, while the coupled flexural-torsional mode refers to the coupled flexural-torsional vibrations of the cantilever beams resulting in rotation of the tip connection. The latter is the main interest of this research. The governing equations of motion and boundary conditions are developed using Hamilton's principle. Two uncoupled equations are realized for each beam: one corresponding to the flexural vibrations and the other one corresponding to the torsional vibrations. The characteristic equations for both the flexural and the coupled flexural-torsional vibration modes are derived and solved to find the natural frequencies corresponding to each mode of vibration. The orthogonality condition among the mode shapes is derived and utilized to determine the modal coefficients corresponding to each mode of vibration. Moreover, the analytical and experimental investigations show that the coupled flexural-torsional fundamental frequency of the structure is dependent on dimensional parameters including the length of the cantilever beams and the length of the tip connection.