Technology Development for Self-Powered Sensors

Abstract

This paper discusses the performance of an acoustic energy harvester employing an electromechanical Helmholtz resonator with a piezoelectric composite backplate. Sufficient energy is available in fluid/acoustic systems to potentially power elements of active flow control systems. Acoustic energy reclamation has been demonstrated using an electromechanical Helmholtz resonator excited by an incident acoustic field, successfully self-powering an electret microphone. The selfpowered microphone calibration shows good agreement with a conventionally powered case. The proof-of-concept demonstration in this paper employed a linear regulator circuit to convert the ac piezoelectric generator voltage into a constant dc voltage.

Efficiency of energy conversion for devices containing a piezoelectric component

“…Consider systems that use a thin PZT film membrane such as the generator concept proposed for a micro heat engine [1] and the concept for harvesting acoustic energy with a Helmholtz resonator [13]. A 1 mm diameter membrane with a 2 µm thick layer of PZT can be expected to yield k 2 values ranging from 1% to 5% and Q values up to 200 [21,22].…”

“…Vibrating structures such as composite piezoelectric cantilever beams have been analysed for their potential to generate electric power from environmental vibrations [12]. A PZT disc mounted to the back of a cavity Helmholtz resonator was developed to harvest acoustic energy [13].…”