An Energy Harvester With Bistable Compliance Characteristics

2010 ◽  
Author(s):  
Andrea Cammarano ◽  
Stephen G. Burrow ◽  
David A. W. Barton
Keyword(s):  
Experimental Approach ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Bistable System ◽  
Complex Dynamic ◽  
Trade Off ◽  
Magnetic Loading ◽  
Electro Magnetic ◽  
Simplified Mathematical Model ◽  
Comparison With Experimental Data

In this paper we present a bistable energy harvesting device. The bi-stability is produced by the particular arrangement of the permanent magnets which form the electro-magnetic transduction mechanism, in conjunction with an iron-cored stator. The harvester features a high magnetic loading but the resulting bistable compliance introduces complex dynamic behaviors. An experimental approach is first used to characterize the device, from which a simplified mathematical model has been developed. The model is then validated by comparison with experimental data. It has been shown that both chaotic and periodic responses are possible. The paper explores the dynamic behavior of the bistable system and attempts to understand the trade-off between the complex mechanical behavior and the benefits of increased magnetic loading.

Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Longhan Xie ◽  
Ruxu Du
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Frequency Tuning ◽  
Nonlinear Behavior ◽  
Stretch Ratio ◽  
Electromagnetic Energy ◽  
Elastic Strings ◽  
Simulation And Experiment ◽  
Frequency Tunable

This paper investigates a frequency-tunable nonlinear electromagnetic energy harvester. The electromagnetic harvester mainly consists of permanent magnets supported on the base to provide a magnetic field, and electrical coils suspended by four even-distributed elastic strings to be an oscillating object. When the base provides external excitation, the electrical coils oscillate in the magnetic field to produce electricity. The stretch length of the elastic strings can be tuned to change their stretch ratio by tuning adjustable screws, which can result in a shift of natural frequency of the harvester system. The transverse force of the elastic strings has nonlinear behavior, which broadens the system's frequency response to improve the performance of the energy harvester. Both simulation and experiment show that the above-discussed electromagnetic energy harvester has nonlinear behavior and frequency-tunable ability, which can be used to improve the effectiveness of energy harvesting.

scholarly journals Analysis of the impact of changes in the stator magnetic circuit on static properties of the electromagnetic linear motor model

2018 ◽  
Vol 67 (3) ◽  
pp. 71-81
Author(s):  
Krzysztof Just ◽  
Paweł Piskur
Keyword(s):  
Magnetic Force ◽  
Permanent Magnets ◽  
Magnetic Circuit ◽  
Evaluation Criteria ◽  
Static Properties ◽  
Independent Variable ◽  
The Mean ◽  
Electro Magnetic ◽  
The Impact ◽  
Maximum Minimum

In this paper, the static characteristics as a function of changes in geometric dimensions of the stator magnetic circuit of the linear stepper actuator with permanent magnets is presented. The stator is built from a series of cylindrical coils encapsulated with ferromagnetic case. The runner is made of permanent magnet rings connected with ferromagnetic spacers. The electromagnetic interac-tion between the stator and the runner for the sequential supply of coils was analyzed. The electro-magnetic force as a function of the geometry of the coils and the ferromagnetic housing for the con-stant graduation of the runner was determined. The maximum, minimum, and average values of the electromagnetic force as a function of the geometric independent variable were determined. The ratio of the mean force to the maximum, and mechanical work calculated as the integral of the force on the path of the runner was adopted as the evaluation criteria. A comparison between the maximum, average and relative values of forces as a function of the geometric dimensions of the stator was made. Keywords: modelling and simulation, linear actuator, finite element method, field calculations, cogging force, magnetic force.

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 Force Characteristics Analysis for Linear Machine with DC Field Excitations

2018 ◽  
Vol 152 ◽  
pp. 03005
Author(s):  
Preshant A/L Krishna ◽  
Aravind CV ◽  
Aminath Saadha ◽  
F. Azhar
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Magnetic Levitation ◽  
Transport Sector ◽  
Magnet System ◽  
Element Analysis ◽  
Average Force ◽  
Railway Systems ◽  
Characteristics Analysis ◽  
Electro Magnetic

In urban regions and particularly in developing countries such as Malaysia with its ever-growing transport sector, there is the need for energy efficient systems. In urban railway systems there is a requirement of frequent braking and start/stop motion, and energy is lost during these processes. To improve the issues of the conventional braking systems, particularly in Japan, they have introduced linear induction motor techniques. The drawbacks of this method, however, is the use of permanent magnets, which not only increase the weight of the entire system but also increases magnetic cogging. Hence an alternative is required which uses the same principles as Magnetic-Levitation but using a magnet-less system. Therefore, the objective of this research is to propose an electromagnetic rail brake system and to analyze the effect of replacing permanent magnets with a magnet-less braking systems to produce a significant amount of brake thrust as compared with the permanent magnet system. The modeling and performance analysis of the model is done using Finite Element Analysis (FEA). The mechanical aspects of the model are designed on Solidworks and then imported to JMAG Software to proceed with the electro-magnetic analysis of the model. There are 3 models developed: Base Model (steel), Permanent Magnet (PM) Model and DC Coil Model. The performance of the proposed 2D models developed is evaluated in terms of average force produced and motor constant square density. By comparing the values for the 3 models for the same case of 9A current supplied for a 0.1mm/s moving velocity, the base model, permanent magnet model and DC coil model produced an average force of 7.78 N, 7.55 N, and 8.34 N respectively, however, with increase in DC current supplied to the DC coil model, the average force produced is increased to 13.32 N. Thus, the advantage of the DC coil (magnet-less) model, is, that the force produced can be controlled by varying the number of turns in the coil (N) or the current supply to the coil (I) given by the which is the simple principles of a solenoid: Force(mmf)=NI.

scholarly journals A Combination of a Vibrational Electromagnetic Energy Harvester and a Giant Magnetoimpedance (GMI) Sensor

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1873
Author(s):  
Juan Jesús Beato-López ◽  
Isaac Royo-Silvestre ◽  
José María Algueta-Miguel ◽  
Cristina Gómez-Polo
Keyword(s):  
Permanent Magnets ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Magnetic Levitation ◽  
Low Cost ◽  
Mechanical Vibration ◽  
Inertial Mass ◽  
Amorphous Wire ◽  
Magnetic Element ◽  
Giant Magnetoimpedance

An energy harvesting device combined with a giant magnetoimpedance (GMI) sensor is presented to analyze low frequency vibrating systems. An electromagnetic harvester based on magnetic levitation is proposed for the electric power generation. The device is composed of two fixed permanent magnets at both ends of a cylindrical frame, a levitating magnet acting as inertial mass and a pick-up coil to collect the induced electromotive force. At the resonance frequency (10 Hz) a maximum electrical power of 1.4 mW at 0.5 g is generated. Moreover, an amorphous wire was employed as sensor nucleus for the design of a linear accelerometer prototype. The sensor is based on the GMI effect where the impedance changes occur as a consequence of the variations of the effective magnetic field due to an oscillating magnetic element. As a result of the magnet’s periodic motion, an amplitude modulated signal (AM) was obtained, its amplitude being proportional to mechanical vibration amplitude (or acceleration). The sensor’s response was examined for a simple ferrite magnet under vibration and compared with that obtained for the vibrational energy harvester. As a result of the small amplitudes of vibration, a linear sensor response was obtained that could be employed in the design of low cost and simple accelerometers.

An Electromagnetic Frequency Increased Vibration Energy Harvester

2011 ◽  
Vol 403-408 ◽  
pp. 4231-4234 ◽  
Author(s):  
Khalid Ashraf ◽  
Mohd Haris Md Khir ◽  
John Ojur Dennis
Keyword(s):  
Permanent Magnets ◽  
Energy Harvester ◽  
Proof Mass ◽  
Excitation Frequency ◽  
Average Power ◽  
Low Frequency ◽  
High Frequency Oscillation ◽  
Vibration Energy ◽  
Frequency Oscillation ◽  
Vibration Energy Harvester

This paper presents an impact-based frequency increased electromagnetic vibration energy harvester to scavenge energy in a low frequency environment. To realize the novel impact based frequency up-conversion mechanism, a coil has been elastically anchored with a platform on which four permanent magnets are arranged in such a way that a strong closed magnetic flux path, linking the coil, is formed. The proposed scavenger has two dynamics of motion. The first phase is a low frequency oscillation to absorb energy from ambient vibration during which both the coil and magnet act as proof mass and move collectively. The increased proof mass ensures maximization of absorbed energy. After crossing a certain clearance, the platform containing magnetic setup rigidly and supporting the coil elastically, collides with a rigid stopper and bounces back. As a result of this mechanical impact a high frequency oscillation is setup in the coil relative to the magnets during which energy is transferred to electrical domain by electromagnetic induction. A macro-prototype has been build to prove the proposed concept. Initial test results show that the proposed harvester generates a peak voltage of 1 volt across a load of 220 Ω at an excitation frequency of 5 Hz which corresponds to a peak power of 4.5 mW and average power of 660 µW.

Investigations of a Stiffness Tunable Nonlinear Vibrational Energy Harvester

2014 ◽  
Vol 14 (08) ◽  
pp. 1440023 ◽  
Author(s):  
Dongxu Su ◽  
Kimihiko Nakano ◽  
Rencheng Zheng ◽  
Matthew P. Cartmell
Keyword(s):  
Energy Harvesting ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Duffing Oscillator ◽  
Experimental Tests ◽  
High Energy ◽  
Practical Implementation ◽  
Energy Harvesting Devices ◽  
Energy Orbit

The recent potential benefit of nonlinearity has been applying in order to improve the effectiveness of energy harvesting devices. For instance, at relatively high excitation levels, both low and high-energy responses can coexist for the same parameter combinations in a hardening type Duffing oscillator, and this provides a wider bandwidth and a higher energy harvesting effectiveness under periodic excitations. However, frequency or amplitude sweeps of the excitation must be used in order to reach a desirable high-energy orbit, and this gives a limitation on practical implementation. This paper presents a stiffness tunable nonlinear vibrational energy harvester which contains a moving magnetic end mass attached to a cantilever beam, whose nonlinearity emerges from the interaction forces with two neighboring permanent magnets facing with opposing poles. The motivating hypothesis has been that the jump from the low-energy orbit to the high-energy orbit can be triggered by tuning the stiffness of the system without changing the frequency or the amplitude of the excitation. Theoretical investigations show a methodology for tuning stiffness, and experimental tests have validated that the proposed method can be used to trigger a jump to the desirable state, and hereby this can broaden the bandwidth of the energy harvester.

A broadband flow energy harvester induced by the wake of a bluff body

2021 ◽  
Author(s):  
Wen-An Jiang ◽  
Xin-dong Ma ◽  
Yong Wang ◽  
Mao Liu ◽  
Li-qun Chen ◽  
...  
Keyword(s):  
Bluff Body ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Analytical Data ◽  
Degree Of Freedom ◽  
Nonlinear Flow ◽  
Physical Parameters ◽  
Restoring Force ◽  
Flow Energy ◽  
Two Degree Of Freedom

Abstract Wake galloping energy harvesting have been extensively developed to scavenge flow energy from vortex-induced oscillations. Hence, the wake-galloping harvester only has a natural frequency which leads to a very narrow bandwidth. Therefore, it does not operate well under the wide region of shedding frequencies in variable wind speed. To overcome the vital issue, this paper we explored a novel two-degree-of-freedom nonlinear flow energy harvester to collect flow energy induced by the wake of a bluff body. The nonlinear restoring force is realized by using a repulsive magnetic force between two cuboid-shaped permanent magnets, and the electromechanical coupling equations is presented. Based on the method of harmonic balance, the electromechanical governing equations is decoupled, and the first order harmonic solutions are implemented. The modulation equations are established, the amplitude-frequency figures of displacement and voltage are depicted with different detuning parameters. The superiority of the presented energy harvester is contrasted with the single-degree-of-freedom linear and nonlinear cases, the results revealed that the two-degree-of-freedom nonlinear scheme can enhance the bandwidth of flow energy capture. The effect of physical parameters on the scavenged power is discussed. The accuracy and efficiency of the approximate analytical data are examined by numerical simulations.

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.

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