Abstract
Tip masses are used in cantilevered piezoelectric energy harvesters to shift device resonance towards the required frequency for harvesting and to improve the electric power generation. Tip masses are typically in the form of concentrated passive weights. The aim of this study is to assess the inclusion of solar panels as active tip masses on the dynamics and power generation performance of cantilevered PVDF (polyvinylidene fluoride)-based vibration energy harvesters. Four different harvester geometries with and without solar panels are realized using off-the-shelf components. Our experimental results show that the flexible solar panels considered in this study are capable of reducing resonance frequency by up to 14% and increasing the PVDF power generated by up to 54%. Two analytical models are developed to investigate this concept; employing both an equivalent concentrated tip mass to represent the case of flexible solar panels and a distributed tip mass to represent rigid panels. Good prediction agreement with experimental results is achieved with an average error in peak power of less than 5% for the cases considered. The models are also used to identify optimum tip mass configurations. For the flexible solar panel model, it is found that the highest PVDF power output is produced when the length of solar panels is two thirds of the total length. On the other hand, results from the rigid solar panel model show that the optimum length of solar panels increases with the relative tip mass ratio, approaching an asymptotic value of half of the total length as the relative tip mass ratio increases significantly.
Highlights
In the modern omni-connected world of Big-Data and the Internet of Things, there is an intense need for the provision of power to small wireless electronic devices
In the case of small angular displacements of the harvester, Rao [24] has shown that an equivalent concentrated tip mass can be estimated by equating the kinetic energy of the actual mass to that of an equivalent mass located at the tip of the harvester
This paper shows the effective use of solar panels as active energy harvesting tip masses for PVDF-based vibration energy harvesters suitable for low frequency applications
Summary
In the modern omni-connected world of Big-Data and the Internet of Things, there is an intense need for the provision of power to small wireless electronic devices. Applications include environmental sensing, equipment and process monitoring, and smart city applications—most of which require robust long-duration operation in remote and sometimes harsh environmental conditions This demand has led to an increasing interest in developing energy harvesting solutions that would act as reliable, affordable, and environmentally friendly power sources for these devices and sensors. Considered a cantilevered structure capable of harvesting energies from base acceleration, solar, and thermal excitations They developed a multilayer cantilever with piezoceramic, thin-film battery, and metallic substructure layers. The primary benefit of attaching a solar panel to the free end of a cantilever beam piezoelectric harvester is clearly the generation of power from solar energy This concept has been demonstrated in preliminary work by the authors [9,10,11] for the case of wind excitation. We compared models to our experiments and against each other, applied them to explore and assess the different possible tip mass configurations to provide a fast evaluation of the optimal design for the harvesters considered in this work
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