Active Performance Optimization of Cantilever Piezoelectric Energy Harvester

Author(s):  
M. Tavakkoli Anbarani ◽  
A. Alasty

A Piezoelectric Energy Harvester (PEH) of cantilever beam type is developed to optimize the generated power by means of active control of moment of inertia of the beam. Distributed parameter equations of vibration of the beam are developed. Then the electromechanical response of the piezoelectric actuator is discussed. The harvester configuration is then described and it is shown that such a configuration can avoid the drastic power drop in presence of uncertainty around resonance frequency by applying voltage to the piezoelectric actuator. Finally the proposed harvester output power working frequency span is compared to conventional methods to show that the significant performance optimization in proposed method is achieved.

Author(s):  
Paulo S. Varoto ◽  
Andreza T. Mineto

It is known that the best performance of a given piezoelectric energy harvester is usually limited to excitation at its fundamental resonance frequency. If the ambient vibration frequency deviates slightly from this resonance condition then the electrical power delivered is drastically reduced. One possible way to increase the frequency range of operation of the harvester is to design vibration harvesters that operate in the nonlinear regime. The main goal of this article is to discuss the potential advantages of introducing nonlinearities in the dynamics of a beam type piezoelectric vibration energy harvester. The device is a cantilever beam partially covered by piezoelectric material with a magnet tip mass at the beam’s free end. Governing equations of motion are derived for the harvester considering the excitation applied at its fixed boundary. Also, we consider the nonlinear constitutive piezoelectric equations in the formulation of the harvester’s electromechanical model. This model is then used in numerical simulations and the results are compared to experimental data from tests on a prototype. Numerical as well as experimental results obtained support the general trend that structural nonlinearities can improve the harvester’s performance.


2014 ◽  
Vol 57 (6) ◽  
pp. 1093-1100 ◽  
Author(s):  
Zhu Liang ◽  
ChunDong Xu ◽  
Bo Ren ◽  
WenNing Di ◽  
Long Li ◽  
...  

Author(s):  
Sihong Zhao ◽  
Alper Erturk

Vibration-based energy harvesting has been heavily researched over the last decade with a primary focus on resonant excitation. However, ambient vibrational energy often has broader frequency content than a single harmonic, and in many cases it is entirely stochastic. As compared to the literature of deterministic energy harvesting, very few authors presented modeling approaches for energy harvesting from broadband random vibrations. These efforts have combined the input statistical information with the single-degree-of-freedom (SDOF) dynamics of the energy harvester to express the statistical electromechanical response characteristics. In most cases, the motion input (base acceleration) is assumed to be ideal white noise. White noise has a flat power spectral density (PSD) that might in fact excite higher vibration modes of an electroelastic energy harvester. In particular, piezoelectric energy harvesters constitute such continuous electroelastic systems with more than one vibration mode. This paper presents modeling and simulations of piezoelectric energy harvesting from broadband random vibrations based on distributed-parameter electroelastic solution. For white noise–type base acceleration of a given PSD level, first the general solution of the distributed-parameter problem is given. Closed-form representations are extracted for the single-mode case and these are analogous to the SDOF equations reported in the literature of energy harvesting. It is reported that the single-mode predictions might result in significant mismatch as compared to multi-mode predictions. Using the electroelastic solution, soft and hard piezoelectric power generators are compared under broadband random excitation. Shunt damping effect of power generation on the stochastic vibration response under broadband random excitation is also reported.


2016 ◽  
Vol 28 (9) ◽  
pp. 1175-1187 ◽  
Author(s):  
Lirong Wang ◽  
Shubin Chen ◽  
Wanlu Zhou ◽  
Tian-Bing Xu ◽  
Lei Zuo

A novel portable energy harvester using 3-3 mode piezoelectric stack with two-stage force amplification is proposed. It can obtain 21 times force amplification with 18% energy transmission ratio and generate electrical energy up to 79 times more than one piezoelectric ceramic of lead zirconate titanate (PZT) stack. Dynamic experiments demonstrate that the harvester with one-and two-stage force amplification can generate the maximum electrical power of 74.9 mW/g2 from one PZT stack at resonance frequency 235 Hz with matching resistance of 268 Ohms and 2642 mW/g2 from three PZT stacks at resonance frequency 37 Hz with match resistance of 1722 Ohm under 100 g proof mass and 0.1 g acceleration. Theoretical electromechanical modeling is established to reveal the working mechanism of force amplification and to predict electricity generation. Comparison of the predicted electricity with experimental results verified effectiveness of electromechanical modeling and optimization design methodology with consideration of tradeoff among force magnification ratio, energy transmission efficiency, and maximum stress. This piezoelectric energy harvester using two-stage force amplification can not only significantly improve power generation but also reduce the resonance frequency Moreover, the resonance frequency can also be adjusted by adjusting the mass load, by which a two-stage energy harvester can be applied to meet requirements of various bandwidths in low-frequency range.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Guang-qing Wang ◽  
Yue-ming Lu

An improved lumped parameter model (ILPM) is proposed which predicts the output characteristics of a piezoelectric vibration energy harvester (PVEH). A correction factor is derived for improving the precisions of lumped parameter models for transverse vibration, by considering the dynamic mode shape and the strain distribution of the PVEH. For a tip mass, variations of the correction factor with PVEH length are presented with curve fitting from numerical solutions. The improved governing motion equations and exact analytical solution of the PVEH excited by persistent base motions are developed. Steady-state electrical and mechanical response expressions are derived for arbitrary frequency excitations. Effects of the structural parameters on the electromechanical outputs of the PVEH and important characteristics of the PVEH, such as short-circuit and open-circuit behaviors, are analyzed numerically in detail. Accuracy of the output performances of the ILPM is identified from the available lumped parameter models and the coupled distributed parameter model. Good agreement is found between the analytical results of the ILPM and the coupled distributed parameter model. The results demonstrate the feasibility of the ILPM as a simple and effective means for enhancing the predictions of the PVEH.


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