Ultra-wide-bandwidth Micro Energy-harvester
A novel ultra-wide-band resonating thin-film PZT MEMS energy-harvester has been developed. It harvests energy from parasitic ambient vibration at a wide range of amplitude and frequency via the piezoelectric effect. Up to this point, the designs of most piezoelectric energy devices have been based on high-Q linear cantilever beams that use the bending strain to generate electrical charge via the piezoelectric effect [1] [2]. They suffer from very small bandwidth and low power density, which prohibit practical use. Contrary to the traditional designs, our new design utilizes the tensile stretching strain in doubly-anchored beams [3]. The resultant stiffness nonlinearity due to the stretching provides a passive feedback and consequently an ultra-wideband resonance [4]. This wide bandwidth of resonance enables a robust power generation amid the uncertainty of the input vibration spectrum. This work includes the design, microfabrication, and testing of a MEMS-scale prototype that aims to harvest up to 0.1mW electrical power in a wide range of excitation frequencies. Mechanical testing has shown 10-fold improvements in the displacement bandwidth. Our simulation predicts 100-fold improvement in the electrical power bandwidth compared to the conventional linear designs. Currently, a new generation of the device is under fabrication and testing at MTL and MNSL facilities.
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- Figure 1: Measured displacement as a function of excitation frequency: 10-fold improvement in the bandwidth can be seen compared to a linear harvester with similar gain.
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- Figure 2: Simulated extractable power as a function of excitation frequency for the new generation of nonlinear energy-harvester: the bandwidth has improved to almost 100% of central frequency to provide an ultra-wideband with energy-harvesting system that shows 100-fold improvements in comparison with typical linear systems.
References
- Y.R. Jeon, Sood, J.H. Jeong, and S.G. Kim, “MEMS power generator with transverse mode thin film PZT,” Sensors and Actuators A: Physical, vol. 122, pp. 16-22, 2005. [↩]
- W.J. Choi, Y. Xia, J.A. Brewer, and S.G. Kim, “Energy harvesting MEMS device based on thin-film piezoelectric cantilevers,” in Proc. of INSS05, San Diego, CA, June 27-28, 2005. [↩]
- A. Hajati and S.G. Kim, “Rectifierless Piezoelectric Micro Power Generator,” SPIE Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring 2008, San Diego, CA, 2008. [↩]
- A. Hajati and S.G. Kim, “Wide Bandwidth MEMS-scale Piezoelectric Energy Harvester,” PowerMEMS09, Washington, DC, 2009. [↩]
Filed under: MEMS & BioMEMS |
Tags: arman hajati, energy harvesting, sang-gook kim
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