Springless Vibration Energy Harvesters

2010 ◽  
Author(s):  
Mohamed A. E. Mahmoud ◽  
Eihab M. Abdel-Rahman ◽  
Raafat R. Mansour ◽  
Ehab F. El-Saadany
Keyword(s):  
Thin Film ◽  
Energy Harvester ◽  
Low Frequency ◽  
Center Frequency ◽  
Vibration Energy ◽  
Restoring Force ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Thin Film Fabrication ◽  
Film Fabrication

A novel vibration energy harvester (VEH) architecture is developed to eliminate the need for restoring force elements (springs) in the VEH. The architecture can realize VEHs with arbitrarily low center frequency. Two prototypes were fabricated and tested to demonstrate the feasibility of this architecture. The center frequency of the first prototype was found to be 2 Hz demonstrating low frequency operation. The second prototype improve the performance by five times at much smaller footprint using thin film fabrication process and precision alignment.

Heartbeat Energy Harvesting Using the Fan-Folded Piezoelectric Beam Geometry

2015 ◽  
Author(s):  
M. H. Ansari ◽  
M. Amin Karami
Keyword(s):  
Natural Frequency ◽  
Energy Harvester ◽  
Low Frequency ◽  
Mode Shapes ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Mechanical Coupling ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam

A three dimensional piezoelectric vibration energy harvester is designed to generate electricity from heartbeat vibrations. The device consists of several bimorph piezoelectric beams stacked on top of each other. These horizontal bimorph beams are connected to each other by rigid vertical beams making a fan-folded geometry. One end of the design is clamped and the other end is free. One major problem in micro-scale piezoelectric energy harvesters is their high natural frequency. The same challenge is faced in development of a compact vibration energy harvester for the low frequency heartbeat vibrations. One way to decrease the natural frequency is to increase the length of the bimorph beam. This approach is not usually practical due to size limitations. By utilizing the fan-folded geometry, the natural frequency is decreased while the size constraints are observed. The required size limit of the energy harvester is 1 cm by 1 cm by 1 cm. In this paper, the natural frequencies and mode shapes of fan-folded energy harvesters are analytically derived. The electro-mechanical coupling has been included in the model for the piezoelectric beam. The design criteria for the device are discussed.

A Novel Broadband Vibration Energy Harvester

2014 ◽  
Vol 644-650 ◽  
pp. 3560-3563
Author(s):  
Yu Liu ◽  
Xiao Yan He ◽  
Shen Liu ◽  
Ying Wu ◽  
Yi Ou
Keyword(s):  
Resonance Frequency ◽  
Energy Harvester ◽  
Engineering Application ◽  
Low Frequency ◽  
Structure Design ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Collector Efficiency ◽  
Energy Acquisition ◽  
Mode Energy

A single resonance frequency is the main factor of limiting vibration energy collector efficiency. In this paper, the multi degree of freedom oscillation adjusting bandwidth scheme is reported, designing a kind of new broadband vibration energy harvester, which has multi-mode energy acquisition, multi freedom vibration and broadband characteristics. Firstly, Broadband energy collector structure design. Secondly, Combining with the main vibration form, using the ANSYS carried out a detailed analysis of its working model. Finally, designing the prototype and doing some experimental verification, the results show that the designed energy collector with low frequency and wideband energy acquisition performance, the frequency domain of energy collection is 57.6 to 69.45HZ ,which break through the bottleneck of traditional single resonance frequency of energy acquisition, has a high value of theory and engineering application.

scholarly journals Ultra-Low Frequency Eccentric Pendulum-Based Electromagnetic Vibrational Energy Harvester

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1009
Author(s):  
Mingxue Li ◽  
Huichao Deng ◽  
Yufeng Zhang ◽  
Kexin Li ◽  
Shijie Huang ◽  
...  
Keyword(s):  
Low Power ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Low Frequency ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Center Frequency ◽  
Vibration Energy ◽  
Outer Side ◽  
Working Frequency

With the development of low-power technology in electronic devices, the wireless sensor network shows great potential in applications in health tracing and ocean monitoring. These scenarios usually contain abundant low-frequency vibration energy, which can be collected through appropriate energy conversion architecture; thus, the common issue of limited battery life in wireless sensor devices could be solved. Traditional energy-converting structures such as the cantilever-beam type or spring-mass type have the problem of high working frequency. In this work, an eccentric pendulum-based electromagnetic vibration energy harvester is designed, analyzed, and verified with the finite element analysis method. The pendulum that contains alternative distributed magnets in the outer side works as a rotor and has the advantages of a simple structure and low center frequency. The structure size is well scalable, and the optimal output performance can be obtained by optimizing the coil thickness and width for a given diameter of the energy harvester. The simulation results show that the energy harvester could work in ultra-low frequencies of 0.2–3.0 Hz. A full-scale prototype of the energy harvester is manufactured and tested. The center working frequency is 2.0 Hz with an average output power of 8.37 mW, which has potential for application in driving low-power wireless sensor nodes.

An enhanced performance of a horizontal diamagnetic levitation mechanism–based vibration energy harvester for low frequency applications

2016 ◽  
Vol 28 (5) ◽  
pp. 578-594 ◽  
Author(s):  
Sri Vikram Palagummi ◽  
Fuh-Gwo Yuan
Keyword(s):  
Figure Of Merit ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Performance Metrics ◽  
Low Frequency ◽  
Experimental System ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Diamagnetic Levitation

This article identifies and studies key parameters that characterize a horizontal diamagnetic levitation mechanism–based low frequency vibration energy harvester with the aim of enhancing performance metrics such as efficiency and volume figure of merit. The horizontal diamagnetic levitation mechanism comprises three permanent magnets and two diamagnetic plates. Two of the magnets, lifting magnets, are placed co-axially at a distance such that each attracts a centrally located magnet, floating magnet, to balance its weight. This floating magnet is flanked closely by two diamagnetic plates which stabilize the levitation in the axial direction. The influence of the geometry of the floating magnet, the lifting magnet, and the diamagnetic plate is parametrically studied to quantify their effects on the size, stability of the levitation mechanism, and the resonant frequency of the floating magnet. For vibration energy harvesting using the horizontal diamagnetic levitation mechanism, a coil geometry and eddy current damping are critically discussed. Based on the analysis, an efficient experimental system is setup which showed a softening frequency response with an average system efficiency of 25.8% and a volume figure of merit of 0.23% when excited at a root mean square acceleration of 0.0546 m/s2 and at a frequency of 1.9 Hz.

scholarly journals Dynamic Modeling and Structural Optimization of a Bistable Electromagnetic Vibration Energy Harvester

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2410 ◽  
Author(s):  
Bei Zhang ◽  
Qichang Zhang ◽  
Wei Wang ◽  
Jianxin Han ◽  
Xiaoli Tang ◽  
...  
Keyword(s):  
Energy Harvester ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Electromagnetic Vibration ◽  
Magnetic Spring ◽  
Element Simulation ◽  
Nonlinear Galerkin Method ◽  
Simulation And Experiment ◽  
The Mathematical Model

A novel bistable electromagnetic vibration energy harvester (BEMH) is constructed and optimized in this study, based on a nonlinear system consisting mainly of a flexible membrane and a magnetic spring. A large-amplitude transverse vibration equation of the system is established with the general nonlinear geometry and magnetic force. Firstly, the mathematical model, considering the higher-order nonlinearities given by nonlinear Galerkin method, is applied to a membrane with a co-axial magnet mass and magnetic spring. Secondly, the steady vibration response of the membrane subjected to a harmonic base motion is obtained, and then the output power considering electromagnetic effect is analytically derived. On this basis, a parametric study in a broad frequency domain has been achieved for the BEMH with different radius ratios and membrane thicknesses. It is demonstrated that model predictions are both in close agreement with results from the finite element simulation and experiment data. Finally, the proposed efficient solution method is used to obtain an optimizing strategy for the design of multi-stable energy harvesters with the similar flexible structure.

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