Broadband Energy Harvesting From Vibrations Using Magnetic Transduction

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Giovanni Caruso

In this paper, an adaptive electromagnetic energy harvester is proposed and analyzed. It is composed of an oscillating mass equipped with an electromagnetic transducer, whose pins are connected to a resonant resistive–inductive–capacitive electric circuit in order to increase its effective bandwidth. Closed-form expressions for the optimal circuit parameters are presented, which maximize the power harvested by the device under harmonic excitation. The harvesting efficiency, defined as the ratio between the harvested power and the power absorbed by the oscillating device, is also reported. It is used as an alternative objective function for the optimization of the harvester circuit parameters.

Author(s):  
Shun Chen ◽  
David Eager ◽  
Liya Zhao

This paper proposes a softening nonlinear aeroelastic galloping energy harvester for enhanced energy harvesting from concurrent wind flow and base vibration. Traditional linear aeroelastic energy harvesters have poor performance with quasi-periodic oscillations when the base vibration frequency deviates from the aeroelastic frequency. The softening nonlinearity in the proposed harvester alters the self-excited galloping frequency and simultaneously extends the large-amplitude base-excited oscillation to a wider frequency range, achieving frequency synchronization over a remarkably broadened bandwidth with periodic oscillations for efficient energy conversion from dual sources. A fully coupled aero-electro-mechanical model is built and validated with measurements on a devised prototype. At a wind speed of 5.5 m/s and base acceleration of 0.1 g, the proposed harvester improves the performance by widening the effective bandwidth by 300% compared to the linear counterpart without sacrificing the voltage level. The influences of nonlinearity configuration, excitation magnitude, and electromechanical coupling strength on the mechanical and electrical behavior are examined. The results of this paper form a baseline for future efficiency enhancement of energy harvesting from concurrent wind and base vibration utilizing monostable stiffness nonlinearities.


Author(s):  
Hieu Nguyen ◽  
Hamzeh Bardaweel

The work presented here investigates a unique design platform for multi-stable energy harvesting using only interaction between magnets. A solid cylindrical magnet is levitated between two stationary magnets. Peripheral magnets are positioned around the casing of the energy harvester to create multiple stable positions. Upon external vibration, kinetic energy is converted into electric energy that is extracted using a coil wrapped around the casing of the harvester. A prototype of the multi-stable energy harvester is fabricated. Monostable and bistable configurations are demonstrated and fully characterized in static and dynamic modes. Compared to traditional multi-stable designs the harvester introduced in this work is compact, occupies less volume, and does not require complex circuitry normally needed for multi-stable harvesters involving piezoelectric elements. At 2.5g [m/s2], results from experiment show that the bistable harvester does not outperform the monostable harvester. At this level of acceleration, the bistable harvester exhibits intrawell motion away from jump frequency. Chaotic motion is observed in the bistable harvester when excited close to jump frequency. Interwell motion that yields high displacement amplitudes and velocities is absent at this acceleration.


Author(s):  
Davide Castagnetti

Energy harvesting from kinetic ambient energy requires converters able to efficiently operate in the low frequency range. A limit of the solutions proposed in the literature, both electromagnetic and piezoelectric, is their operating frequency, which generally ranges from about 50 to 300 Hz. To overcome these limitations, this work proposes an innovative energy harvester exploiting two counteracting Belleville springs. Thanks to the peculiar height to thickness ratio of the springs a highly compliant elastic system is obtained, which can be used either for electromagnetic or piezoelectric harvesting. The harvester is modelled analytically and numerically both with regard to the force-displacement and to the modal response. The experimental validation of the harvester, highlights a noticeable power output but at a higher eigenfrequency than expected.


Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 457
Author(s):  
Ryan G. Hall ◽  
Reza Rashidi

This paper discusses the development of a multi-directional, universal, electromagnetic energy harvester. The device is a ball consisting of two parts: a rigid spherical core with internal tubes, coils and magnets, and a flexible silicone-based shell holding a carrier fluid. The multi-directional aspect of the design comes from the device’s spherical shape. The harvester generates energy when subject to compressive force, by moving fluid through a tube, pushing a permanently magnetized ball through a coil wound around the tube. A combination of 3-D printed PLA plastic and molded silicone was used to produce a prototype. The energy harvester can be utilized in applications where there is an oscillating compression and it is not limited to certain applications due to its universal ball shape. It was tested at five different frequencies between 4–15 Hz on its four different outer sides producing electricity at a range of 17 to 44 mV.


Author(s):  
Mohamed M. R. El-Hebeary ◽  
Mustafa H. Arafa ◽  
Said M. Megahed

The focus of the present work is on the design of plate structures for vibration energy harvesting from two closely-spaced modes of vibration. The work is motivated by the quest to design resonators that respond to variable-frequency sources of base motion. The geometry of two-dimensional structures, such as trapezoidal and V-shaped plates, is explored to obtain two closely-spaced harvestable vibration modes to scavenge energy across a broader bandwidth. To this end, an electromagnetic energy harvester in the form of a base excited plate is proposed. The plate carries tip magnets that oscillate past stationary coils to generate power from the first two modes of vibration. The plate dynamic behavior is governed by its geometry and placement of the magnets on its tip. An effort is made to optimize the system configuration so as to control the spacing between the resonance frequencies while efficiently harvesting energy from both modes. Findings of the present work are verified both numerically and experimentally.


Author(s):  
Yu Pan ◽  
Fengwei Liu ◽  
Ruijin Jiang ◽  
Zhiwen Tu ◽  
Lei Zuo

To enable the smart technologies, such as the GPS, suspension active and semi-active controls and electromagnetic braking system, on the railway freight vehicles, the electricity is required and in needed. In this paper, we proposed a rack-pinion based freight train suspension energy harvester with mechanical-motion-rectifier (MMR) mechanism, to harvest the energy that usually dissipated and wasted during suspension vibration. The special mechanism with one way clutches engagement and disengagement during the working period makes the harvester convert the bi-direction suspension linear motion into a generator unidirectional rotation, which improve the transmission reliability and increase the energy harvesting efficiency. Nonlinear model of the energy harvester is established in this paper to analyze the dynamic characteristic of the freight train energy harvester and bench test are carried out to experimentally characterize the proposed energy harvester. The results show that under a certain freight vehicle suspension vibration condition, the proposed energy harvester can get a peak 292W and an average 34W power, which has a much better energy harvesting performance than any other existing energy harvesting technology used for the railway vehicles. Moreover, the proposed energy harvester can reach a 70% mechanical efficiency, which shows that the MMR’s advantage in improving the energy harvesting efficiency.


Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4277 ◽  
Author(s):  
Maoying Zhou ◽  
Mohannad Al-Furjan ◽  
Ban Wang

This paper proposes and investigates a piezoelectric energy harvesting system based on the flow induced vibration of a piezoelectric composite cantilever pipe. Dynamic equations for the proposed energy harvester are derived considering the fluid-structure interaction and piezoelectric coupling vibration. Linear global stability analysis of the fluid-solid-electric coupled system is done using the numerical continuation method to find the neutrally stable vibration mode of the system. A measure of the energy harvesting efficiency of the system is proposed and analyzed. A series of simulations are conducted to throw light upon the influences of mass ratio, dimensionless electromechanical coupling, and dimensionless connected resistance upon the critical reduced velocity and the normalized energy harvesting efficiency. The results provide useful guidelines for the practical design of piezoelectric energy harvester based on fluid structure interaction and indicate some future topics to be investigated to optimize the device performance.


Author(s):  
Alper Erturk ◽  
Ho-Yong Lee ◽  
Daniel J. Inman

Piezoelectric materials have received the most attention for vibration-to-electricity conversion over the last decade. Harmonic excitation is the most commonly investigated form of excitation in piezoelectric energy harvesting and it can be divided into two subgroups as resonant and off-resonant excitations. Although resonant excitation is preferred for extracting the maximum electrical power output from the device, there are several practical cases where it is not possible to excite the energy harvester at its resonance frequency (e.g. varying frequency excitations or very low frequency excitations where the input frequency is much lower than the fundamental resonance frequency). Several researchers have used soft piezoceramics (e.g. PZT-5A and PZT-5H) for power generation under resonant excitation. Typically, these soft piezoceramics have larger piezoelectric strain constant and larger elastic compliance compared to hard piezoceramics (e.g. PZT-4 and PZT-8). However, it is known that hard piezoceramics can have an order of magnitude larger mechanical quality factor compared to soft piezoceramics. Consequently, hard piezoceramics can generate more power under resonant excitation even though researchers have mostly focused on the soft piezoceramics. On the other hand, soft piezoceramics can generate more power for low frequency excitation below the resonance frequency due to their large effective piezoelectric stress constants. This difference is also the case for soft and hard single crystals (e.g. soft PMN-PZT versus hard PMN-PZT-Mn). In addition, single crystals can generate more power than ceramics at low off-resonant frequencies due to their large dynamic flexibilities (which is related to their large elastic compliances). This work investigates the specific advantages of soft and hard piezoceramics and single crystals for vibration-based energy harvesting. An experimentally validated piezoelectric energy harvester model is used to compare the power generation performances of soft and hard ceramics as well as soft and hard single crystals. The soft and the hard piezoceramics considered in this work are PZT-5H and PZT-8, respectively, while the soft and the hard single crystals considered here are PMN-PZT and PMN-PZT-Mn, respectively.


Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1300
Author(s):  
Xiang Li ◽  
Jinpeng Meng ◽  
Chongqiu Yang ◽  
Huirong Zhang ◽  
Leian Zhang ◽  
...  

In this paper, a magnetically coupled electromagnetic energy harvester (MCEEH) is proposed for harvesting human body kinetic energy. The proposed MCEEH mainly consists of a pair of spring-connected magnets, coils, and a free-moving magnet. Specifically, the interaction force between the magnets is repulsive. The main feature of this structure is the use of a magnetic-spring structure to weaken the hardening response caused by the repulsive force. The magnetic coupling method enables the energy harvester system to harvest energy efficiently at low frequency. The MCEEH is experimentally investigated for improving energy harvesting efficiency. Under harmonic excitation with an acceleration of 0.5 g, the MCEEH reaches resonance frequency at 8.8 Hz and the maximum output power of the three coils are 5.2 mW, 2.8 mW, and 2.5 mW, respectively. In the case of hand-shaking excitation, the generator can obtain the maximum voltage of 0.6 V under the excitation acceleration of 0.2 g and the excitation frequency of 3.4 Hz. Additionally, a maximum instantaneous power can be obtained of about 26 mW from the human body’s kinetic energy


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