Optimizing Piezoelectric Energy Harvesting from Mechanical Vibration for Electrical Efficiency: A Comprehensive Review

Abstract

In the current era, energy resources from the environment via piezoelectric materials are not only used for self-powered electronic devices, but also play a significant role in creating a pleasant living environment. Piezoelectric materials have the potential to produce energy from micro to milliwatts of power depending on the ambient conditions. The energy obtained from these materials is used for powering small electronic devices such as sensors, health monitoring devices, and various smart electronic gadgets like watches, personal computers, and cameras. These reviews explain the comprehensive concepts related to piezoelectric (classical and non-classical) materials, energy harvesting from the mechanical vibration of piezoelectric materials, structural modelling, and their optimization. Non-conventional smart materials, such as polyceramics, polymers, or composite piezoelectric materials, stand out due to their slender actuator and sensor profiles, offering superior performance, flexibility, and reliability at competitive costs despite their susceptibility to performance fluctuations caused by temperature variations. Accurate modeling and performance optimization, employing analytical, numerical, and experimental methodologies are imperative. This review also furthers research and development in optimizing piezoelectric energy utilization, suggesting the need for continued experimentation to select optimal materials and structures for various energy applications.

Analysis of the Methods for Realization of Low-Power Piezoelectric Energy Harvesting Circuits for Wearable Battery-Free Power Supply Devices

“…The MEMSs have revolutionized the field of energy harvesting, providing highly efficient and compact solutions for powering small electronic devices [32,33]. When compared to traditional flexible-foil-based wearable piezoelectric generators, MEMS piezoelectric energy harvesting elements offer several distinct advantages.…”

“…-Energy conversion efficiency: This is a key factor in determining the overall performance of the harvester in converting mechanical vibrations into electrical energy, which is very often expressed by the output power or by power density for an activated volume of material. In this regard, typical values for the output power are in the range of 800 nW to 14 W [32], according to the cantilever shape and the material's crystal structure and thickness, and for the power density, they are in the range of 3 µW/mm 3 -3 mW/cm 3 [37]. -Size/dimensions: These devices can be miniaturized to dimensions ranging from a few millimeters down to sub-millimeter scales, with thicknesses typically falling in the range of tens to hundreds of micrometers.…”

“…The inductance of the coil is chosen to be as large as possible so that when the switch is open current values below the minimum value I o,min (in which the current through the coil reaches zero during the time interval when the switch is open) are not reached [15,32]:…”