A geometric parameter study of piezoelectric coverage on a rectangular cantilever energy harvester

Abstract

This paper proposes a versatile model for optimizing the performance of a rectangular cantilever beam piezoelectric energy harvester used to convert ambient vibrations into electrical energy. The developed model accounts for geometric changes to the natural frequencies, mode shapes and damping in the structure. This is achieved through the combination of finite element modelling and a distributed parameter electromechanical model, including load resistor and charging capacitor models. The model has the potential for use in investigating the influence of numerous geometric changes on harvester performance, and incorporates a model for accounting for changes in damping as the geometry changes. The model is used to investigate the effects of substrate and piezoelectric layer length, and piezoelectric layer thickness on the performance of a microscale device. Findings from a parameter study indicate the existence of an optimum sample length due to increased mechanical damping for longer beams and improved power output using thicker piezoelectric layers. In practice, harvester design is normally based around a fixed operating frequency for a particular application, and improved performance is often achieved by operating at or near resonance. To achieve unbiased comparisons between different harvester designs, parameter studies are performed by changing multiple parameters simultaneously with the natural frequency held fixed. Performance enhancements were observed using shorter piezoelectric layers as compared to the conventional design, in which the piezoelectric layer and substrate are of equal length.

Electrode Coverage Optimization for Piezoelectric Energy Harvesting from Tip Excitation

“…Maximum power output can be obtained for a certain length of the transducer layer. Patel et al developed a comprehensive theoretical model for analysing piezoelectric cantilever beams with varying length and thickness of the piezoelectric layer [ 11 ]. These two parameters proved to be significant for increasing the output power.…”

Performance improvement of piezoelectric materials in energy harvesting in recent days – a review

“…Patel et al, experimented on a rectangular cantilever by applying constant acceleration at a weight of 2 g and concentrated on the control parameters, tip mass inertia and substrate thickness mainly [43].…”

Design of a prototype generator based on piezoelectric power generation for vibration energy harvesting

“…Several articles and significant research have been devoted to developing and understanding power-harvesting systems, with an emphasis on piezoelectric conversion to generate electricity from vibrations [4][5][6][7][8][9][10][11][12][13]. These studies demonstrated the feasibility of using piezoelectric materials as power sources.…”

“…The design comprises a multimode intermediate beam with a tip mass, called a dynamic magnifier. Patel et al [13] proposed a versatile model for optimising the performance of a rectangular cantilever beam piezoelectric energy harvester used to convert ambient vibrations into electrical energy. The developed model accounts for geometric changes to the natural frequencies, mode shapes, and damping in the structure.…”