scholarly journals A Comparison of Methods to Measure the Coupling Coefficient of Electromagnetic Vibration Energy Harvesters

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 826 ◽  
Author(s):  
Mario Mösch ◽  
Gerhard Fischerauer
Keyword(s):  
Coupling Coefficient ◽  
Energy Harvester ◽  
Electromagnetic Coupling ◽  
Electric Circuit ◽  
Open Circuit ◽  
Measurement Methods ◽  
Vibration Energy ◽  
Simulation Data ◽  
Average Deviation ◽  
Energy Harvesters

Vibration energy harvesters transform environmental vibration energy into usable electrical energy. The transformation is only possible because of a coupling between the mechanical part of the energy harvester and the electric circuit. This paper compares several measurement methods to determine the electromagnetic coupling coefficient. These methods are applied to various implementations of an energy harvester and the results are compared with one another and with simulation data by analyzing the magnetic flux. The average deviation between the measurement methods and the simulation data in our study was 5%. This good agreement validates the methods. Based on this, we recommend determination of the coupling coefficient and the optimum load resistance for maximum power harvesting on the basis of simulations and the open circuit method, because this procedure leads to the shortest measurement times.

scholarly journals Vibration Energy Harvester Based on Torsionally Oscillating Magnet

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1545
Author(s):  
Xinyi Wang ◽  
Jiaxing Li ◽  
Chenyuan Zhou ◽  
Kai Tao ◽  
Dayong Qiao ◽  
...  
Keyword(s):  
Energy Harvester ◽  
Proof Mass ◽  
Vibrational Energy ◽  
Open Circuit ◽  
Vibration Energy ◽  
Peak Voltage ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Cantilever Structure ◽  
Sinusoidal Excitation

Most of the miniaturized electromagnetic vibrational energy harvesters (EVEHs) are based on oscillating proof mass suspended by several springs or a cantilever structure. Such structural feature limits the miniaturization of the device’s footprint. This paper presents an EVEH device based on a torsional vibrating magnet over a stack of flexible planar coils. The torsional movement of the magnet is enabled by microfabricated silicon torsional springs, which effectively reduce the footprint of the device. With a size of 1 cm × 1 cm × 1.08 cm, the proposed EVEH is capable of generating an open-circuit peak-to-peak voltage of 169 mV and a power of 6.9 μW, under a sinusoidal excitation of ±0.5 g (g = 9.8 m/s2) and frequency of 96 Hz. At elevated acceleration levels, the maximum peak-to-peak output voltage is 222 mV under the acceleration of 7 g (±3.5 g).

Performance analysis of a lever piezoelectric energy harvester for roadway applications

2021 ◽  
pp. 1045389X2110014
Author(s):  
Guangya Ding ◽  
Hongjun Luo ◽  
Jun Wang ◽  
Guohui Yuan
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Open Circuit ◽  
Traffic Load ◽  
Energy Harvesters ◽  
Speed Sensor ◽  
Piezoelectric Energy ◽  
Optimal Load ◽  
Self Powered ◽  
Output Characteristics

A novel lever piezoelectric energy harvester (LPEH) was designed for installation in an actual roadway for energy harvesting. The model incorporates a lever module that amplifies the applied traffic load and transmits it to the piezoelectric ceramic. To observe the piezoelectric growth benefits of the optimized LPEH structure, the output characteristics and durability of two energy harvesters, the LPEH and a piezoelectric energy harvester (PEH) without a lever, were measured and compared by carrying out piezoelectric performance tests and traffic model experiments. Under the same loading condition, the open circuit voltages of the LPEH and PEH were 20.6 and 11.7 V, respectively, which represents a 76% voltage increase for the LPEH compared to the PEH. The output power of the LPEH was 21.51 mW at the optimal load, which was three times higher than that of the PEH (7.45 mW). The output power was linearly dependent on frequency and load, implying the potential application of the module as a self-powered speed sensor. When tested during 300,000 loading cycles, the LPEH still exhibited stable structural performance and durability.

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.

On Mathematical Modeling of Piezoelectric Energy Harvesters

2014 ◽  
Vol 953-954 ◽  
pp. 655-658 ◽  
Author(s):  
Guang Qing Shang ◽  
Hong Bing Wang ◽  
Chun Hua Sun
Keyword(s):  
Mathematical Modeling ◽  
Energy Harvesting ◽  
Energy Harvester ◽  
Vibration Energy ◽  
Piezoelectric Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Energy Harvesting System ◽  
Piezoelectric Vibration

Energy harvesting system has become one of important areas of ​​research and develops rapidly. How to improve the performance of the piezoelectric vibration energy harvester is a key issue in engineering applications. There are many literature on piezoelectric energy harvesting. The paper places focus on summarizing these literature of mathematical modeling of piezoelectric energy harvesting, ranging from the linear to nonlinear, from early a single mechanical degree to piezoaeroelastic problems.

Multi-Modal Vibration Energy Harvesting Using a Trapezoidal Plate

2011 ◽  
Author(s):  
Mustafa H. Arafa
Keyword(s):  
System Performance ◽  
Energy Harvester ◽  
Natural Frequencies ◽  
Vibration Energy ◽  
Vibration Modes ◽  
Vibration Energy Harvesting ◽  
Energy Harvesters ◽  
Trapezoidal Plate ◽  
Plate Geometry ◽  
Modal Vibration

Vibration-based energy harvesters are usually designed to exhibit natural frequencies that match those of the excitation for maximum power output. This has spurred interest into the design of devices that respond to variable frequency sources. In this work, an electromagnetic energy harvester in the form of a base excited trapezoidal plate is proposed. The plate geometry is designed to achieve two closely spaced vibration modes in order to harvest energy across a broader bandwidth. The ensuing bending and twisting vibrations are utilized in this capacity by placing a magnet on the plate tip that moves past a stationary coil. A dynamic model is presented to predict the system performance and is verified experimentally.

Design and Comparison of Micro Electromagnetic Vibration Energy Harvesters

2015 ◽  
Vol 645-646 ◽  
pp. 1223-1232
Author(s):  
Yi Ming Lei ◽  
Zhi Yu Wen ◽  
Li Chen
Keyword(s):  
Energy Harvester ◽  
Load Resistance ◽  
Vibration Energy ◽  
Test Results ◽  
Peak Voltage ◽  
Energy Harvesters ◽  
Electromagnetic Vibration ◽  
Mems Technology ◽  
Electromagnetic Energy Harvesting ◽  
Linear Spring

This paper presents two electromagnetic vibration energy harvesters based on micro-electro-mechanical (MEMS) technology. Two prototypes with different vibration structures were designed and fabricated. The energy harvester includes a permanent magnet attached on vibration structure (resonator) made by Si and a fixed wire-wound coil, with the total volume of 0.9 cm3. Two energy harvesters with different resonator are tested and compared. Experiments show that: in the same acceleration and a load resistance, the resonant frequency of prototype B is approximately 95% of prototype A; The peak-peak voltage and the maximum power of prototype B is 1.6 times and 2.7 times of prototype A respectively. The test results was analyzed simply and it indicated that the electromagnetic energy harvesting with the spring B has better performance; also proved that the potential ability of the non-linear spring could extend the frequency bandwidth and improve output voltage.

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.

scholarly journals Development and Validation of an Enhanced Coupled-Field Model for PZT Cantilever Bimorph Energy Harvester

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Long Zhang ◽  
Keith A. Williams ◽  
Zhengchao Xie
Keyword(s):  
Energy Harvester ◽  
Field Model ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Open Circuit ◽  
Conservation Of Energy ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Comparison Results ◽  
Coupled Field

The power source with the limited life span has motivated the development of the energy harvesters that can scavenge the ambient environment energy and convert it into the electrical energy. With the coupled field characteristics of structure to electricity, piezoelectric energy harvesters are under consideration as a means of converting the mechanical energy to the electrical energy, with the goal of realizing completely self-powered sensor systems. In this paper, two previous models in the literatures for predicting the open-circuit and close-circuit voltages of a piezoelectric cantilever bimorph (PCB) energy harvester are first described, that is, the mechanical equivalent spring mass-damper model and the electrical equivalent circuit model. Then, the development of an enhanced coupled field model for the PCB energy harvester based on another previous model in the literature using a conservation of energy method is presented. Further, the laboratory experiments are carried out to evaluate the enhanced coupled field model and the other two previous models in the literatures. The comparison results show that the enhanced coupled field model can better predict the open-circuit and close-circuit voltages of the PCB energy harvester with a proof mass bonded at the free end of the structure in order to increase the energy-harvesting level of the system.

scholarly journals Topology Selection and Parametric Design of Electromagnetic Vibration Energy Harvesters by Combining FEA-in-the-Loop and Analytical Approaches

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 627 ◽  
Author(s):  
Seong-yeol Yoo ◽  
Young-Woo Park ◽  
Myounggyu Noh
Keyword(s):  
Output Power ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Maximum Output Power ◽  
Electromagnetic Energy ◽  
Vibration Energy ◽  
Maximum Output ◽  
Primary Concern ◽  
Energy Harvesters ◽  
Analytical Approaches

Electromagnetic energy harvesters have been used to capture low-frequency vibration energy of large machines such as diesel generators. The structure of an electromagnetic energy harvester is either planar or tubular. Past research efforts focus on optimally designing each structure separately. An objective comparison between the two structures is necessary in order to decide which structure is advantageous. When comparing the structures, the design variations such as magnetization patterns and the use of yokes must also be considered. In this study, extensive comparisons are made covering all possible topologies of an electromagnetic energy harvester. A bench mark harvester is defined and the parameters that produce maximum output power are identified for each topology. It is found that the tubular harvesters generally produce larger output power than the planar counterparts. The largest output power is generated by the tubular harvester with a Halbach magnetization pattern (94.7 mW). The second best is the tubular harvester with axial magnetization pattern (79.1 mW) when moving yokes are inserted between permanent magnets for flux concentration. When cost is of primary concern, the tubular harvester with axial pattern may become a best option.

Trends of MEMS-Based Vibration Energy Harvester

2013 ◽  
Vol 562-565 ◽  
pp. 1251-1256
Author(s):  
Bing Mo ◽  
Rong Hai Huang ◽  
Rui Min Huang ◽  
Chao Dong Ling ◽  
Huo Zhou
Keyword(s):  
Wireless Sensor Networks ◽  
Power Management ◽  
Energy Harvester ◽  
Ambient Vibration ◽  
Wireless Sensor ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Prospective Development ◽  
Energy Harvesters ◽  
Micro Vibration

Micro vibration energy harvesters have received much attention due to their potential application of low power wireless sensor networks and embedded systems. This paper studies three mechanisms to scavenge the ambient vibration energy, discusses the power management circuit and the application of the converter, investigates the prospective development and ongoing challenges in MEMS-based vibration energy harvester.

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