Electromagnetic Energy Harvester Research Articles

Efficiency evaluation of the enhanced nonlinear energy sink with electromagnetic energy harvesting mechanism

Nonlinear energy sinks (NESs) have received considerable attention in vibration suppression, and the optimal design around the stiffness and damping is considered the key to achieving improved performance. This paper investigates the tri-magnet monostable and bistable enhanced NESs with electromagnetic energy harvesting mechanism. A comprehensive evaluation of the absorption and harvesting efficiency of the enhanced NES is conducted. The tri-magnet structure is developed further to realize both monostable and bistable configurations. Then, an enhanced series coils energy conversion element based on the electromagnetic energy harvesting mechanism is proposed for damping adjustment. The NES is attached to the cantilever beam subject to transient excitations. Furthermore, the equivalent model of the cantilever beam with an NES is obtained by exploiting the extended Hamilton’s principle. An optimization design method that considers both vibration absorption and harvesting efficiency is provided. The instantaneous energy variations of the optimized monostable and bistable NESs are discussed based on simulation and experimental results. Finally, the experiments with two load modes, R load and C load, demonstrate the effectiveness of the enhanced NESs in vibration absorption and its promising application in energy harvesting.

Low-frequency human motion energy scavenging with wearable tumbler-inspired electromagnetic energy harvesters

Harvesting energy from human motion to power portable electronic devices has attracted widespread attention. However, human motion energy is primarily concentrated in low-frequency range below 5 Hz, which makes it hard to capture with traditional approaches. In this work, a tumbler-inspired electromagnetic energy harvester (T-EMH) is designed to harvest human motion energy. The magnet is placed on the top of the tumbler structure, allowing for easy conversion of irregular human motion into electricity through the tumbler mechanism. A theoretical model is established to predict the energy harvesting performance of T-EMH. Both simulations and experiments were conducted to verify the low-frequency characteristics of T-EMH. The harvested maximum peak voltage is 0.6 V and the maximum average output power can reach 0.55 mW by adjusting the external load. Additionally, human motion tests substantiate T-EMH's capacity to generate a peak power output of 0.86 mW at a running speed of 12 km/h. These results emphasize the promising potential of T-EMH as an effective approach for capturing energy from human motion.

Energy recovery from a system with double magnet. Analytical approach

The main goal of the research presented in this paper is to find an analytical solution for an electromagnetic energy harvester with double magnet. A double magnet configuration is defined as a structure in which two magnets, either attracting or repelling, are positioned at a constant distance from each other. Analytical dependencies that govern the shape of electromechanical coupling coefficient curves for various double magnet configurations are provided. In the subsequent step of the analysis, resonance curves for its vibrations and the corresponding recovered energy were determined for the selected dual magnet settings using the harmonic balance method. These characteristics enabled us to ascertain the optimal resistance and estimate the maximum electrical power that can be harvested from the vibrations of the double magnets.

Nonlinear electromagnetic vibration energy harvester comprising dual helical-plane springs and multiple Halbach arrays for low-frequency and small-amplitude vibrations

Electromagnetic vibration energy harvesters are widely investigated for self-powered wireless sensors and nonlinearity has been introduced for low-frequency and broadband vibration energy harvesting. But how to realize the nonlinearity with small amplitudes, high reliability and few complexities is still a challenge in real-world applications. In this paper, a novel electromagnetic vibration energy harvester comprising dual helical-plane springs and multiple Halbach arrays is proposed. The structural characteristics are analyzed, which indicate that the helical-plane springs can have nonlinear stiffness under small-amplitude vibrations and multiple Halbach arrays can greatly enhance the magnetic field. Then a magnet-electro-mechanical model is built by combining mechanical dynamics &electrodynamics, which is numerically solved by using the Runge-Kutta algorithm. Finally, the feasibility of the nonlinear electromagnetic vibration energy harvester is validated both numerically and experimentally. The results show that it has a nonlinear stiffness, a resonance bandwidth of 3 Hz and a peak power of 14 mW when the excitation amplitude is only 0.5 g. In particular, the resonance frequency range depends on the excitation amplitude. Furthermore, the prototype of a self-powered wireless temperature sensor is constructed and testified. The results of this study indicate that the proposed structure can be utilized and extended to build compact, reliable and nonlinear electromagnetic vibration energy harvesters for low-frequency, small-amplitude and broadband vibrations in real-world applications.

Frequency tunable electromagnetic vibration energy harvester based on diamagnetic levitation

Frequency tunable electromagnetic vibration energy harvester based on diamagnetic levitation

Design, Optimization, and Application of Nonlinear Energy Sink in Energy Harvesting Device

Vibration control has been of great interest to scientists and engineers for many years. Although linear vibration absorbers have been shown to be effective in mitigating vibrations at specific frequencies, their vibration reduction effect is usually limited to a narrow frequency bandwidth. Nonlinear energy sinks have attracted attention due to their better vibration reduction effect over a wider frequency bandwidth. In practical applications, the nonlinear energy sink devices can effectively absorb, dissipate, and convert energy from broadband excitation, so as to achieve vibration reduction and energy harvesting. However, research on energy harvesting based on the nonlinear energy sink is less mature than in linear systems. Multiple parameters of device design (e.g., damping size) affect the actual performance of the nonlinear energy sinks, but there is no exact method to simplify the design of the multiparameter nonlinear energy sinks. Since it is more difficult to implement electromagnetic and electrostatic energy harvesters, more research has focused on piezoelectric energy harvesters. This paper summarizes the research on the nonlinear energy sink and energy harvesting technology, including the introduction of the nonlinear energy sink, energy harvesting based on the nonlinear energy sink, and its application in various fields of energy harvesting. The paper also summarizes some important methods for solving the dynamical equations, as well as their advantages and disadvantages. The conclusions provide an outlook on the subsequent research of the nonlinear energy sink technology, such as the introduction of piezoelectric materials with high energy density, the benefits of balanced vibration suppression and harvesting of vibration energy, and the self-tuning of parameters in complex environments. It provides a powerful reference for the popularization and application of energy harvesting technology based on nonlinear energy sinks.

A walking energy harvesting device based on miniature water turbine

The rapid development of wearable electronics highlights the urgence to develop the portable energy harvester with excellent output performance, comfortability, and sustainability. This work designs an electromagnetic walking energy harvester based on water turbine that can be embedded in shoes with good comfortability. Its working principle is that the walking generated pressure energy drives a miniature hydraulic turbine to output electricity. Experimental results show that an average power of 300 and 180 mW can be produced at heel and toe, respectively, when a man of 80 kg walks at a speed of 1.8 m s−1. This power output exceeds the piezoelectric, triboelectric, and electromagnetic walking energy harvesters reported in the past. Additionally, the simpler structure endows it better comfortability as compared with the electrostatic capacitances. Computational fluid dynamics simulations provide a further insight that the efficiency of turbine can reach 13.5% by optimizing parameters of blade number and outlet flow ratio. Finally, user real-time positioning and trajectory recording are successfully demonstrated via a wearable GPS means Global Positioning System module powered by the harvester. Due to the combination of high output performance, simple structure and low discomfort, the water turbine based walking energy harvester will provide a wide application potential in wearable devices.

Investigative Study of the Effect of Damping and Stiffness Nonlinearities on an Electromagnetic Energy Harvester at Low-Frequency Excitations

Ambient vibration energy is widely being harnessed as a source of electrical energy to drive low-power devices. The vibration energy harvester (VEH) of interest employs an electromagnetic transduction mechanism, whereby ambient mechanical vibration is converted to electrical energy. The limitations affecting the performance of VEHs, with an electromagnetic transduction structure, include its operational bandwidth as well as the enclosure-size constraint. In this study, an analysis and design of a nonlinear VEH system is conducted using the Output Frequency Response Function (OFRF) representations of the actual system model. However, the OFRF representations are determined from the Generalised Associated Linear Equation (GALE) decompositions of the system of interest. The effect of both nonlinear damping and stiffness characteristics, to, respectively, extend the average power and operational bandwidth of the VEH device, is demonstrated.

Design of Electro-Magnetic Energy Harvester (EMEH) From Knee’s Muscle Work During Walking

Design of Electro-Magnetic Energy Harvester (EMEH) From Knee’s Muscle Work During Walking

Sustainable Solutions in Sound Shielding: Harnessing Metamaterials for Acoustic Cloaking

The development of metamaterials promises to enable smallscale, worldwide industry-wide acoustic, electromagnetic, mechanical, and solar energy harvesting. Engineered structures surpass natural material limitations, offering capabilities unattainable in traditional counterparts. This paper explores metamaterials' manipulation of acoustic, electromagnetic, mechanical, and solar energy. Mechanical metamaterials convert strain into electrical energy, applicable from interstellar travel to terrestrial infrastructure. Precision-configured acoustic metamaterials efficiently harness dispersed acoustic energy, improving renewable energy methodologies. Integration into photovoltaic cells showcases metamaterials' solar potential, with innovative designs enhancing solar energy conversion efficiency. “Metamaterials” is a word used to describe artificial structures whose properties are based on the aggregate expression of individual components. Acoustic metamaterials are the term used for such constructions intended for the manipulation of acoustic waves. Controlled wave propagation is made possible by acoustic metamaterials, which is frequently not possible with bulk materials created chemically. This indicates that the wave propagation in acoustic metamaterials is directed and produces desired acoustic effects, independent of the mass-density properties of the material. The distinct properties of acoustic metamaterials have paved the way for the creation of practical solutions for a variety of uses, such as passive destructive interference, acoustic cloaking, sound focusing, low-frequency sound insulation, and biomedical acoustics. The kind of sound modification determines the general properties of an acoustic metamaterial. The properties of several of the most promising acoustic metamaterials from passive to active are introduced in this work. In order to achieve a sustainable future, it is necessary to combine environmentally friendly technologies with renewable energy sources for their final application. This is demonstrated by highlighting both the fundamental concepts and the physical models that were assessed.

A Dual-Polarized, Notched Electromagnetic Energy Harvester Array Based on FSS

A Dual-Polarized, Notched Electromagnetic Energy Harvester Array Based on FSS

A Synchronous Current Inversion and Energy Extraction Circuit for Electromagnetic Energy Harvesting Enhancement

A Synchronous Current Inversion and Energy Extraction Circuit for Electromagnetic Energy Harvesting Enhancement

A hybrid energy harvester inspired by bionic flapping wing structure based on magnetic levitation.

A hybrid energy harvester based on magnetic levitation is inspired by the structure of the flapping wing, which consists of two parts: one is a flapping wing structure mounted with a piezoelectric sheet, which can achieve piezoelectric energy harvesting; the other is an intermediate muscle unit, which is vertically arranged by three groups of permanent magnets to achieve magnetic levitation electromagnetic energy harvesting. An electromechanical-electromagnetic coupling model of this harvester is established based on electromechanical coupling characteristics. The simulation analysis can evaluate the magnetic field distribution and nonlinear magnetic properties and also analyze its effects on the output performance. Several experiments are designed to verify the effectiveness of the hybrid energy harvesting structure and to check the influence of the number of magnets on the output power. The maximum output power of the proposed structure can generate 13.61 mW at 4.5Hz excitation.

A compact-sized four-band metamaterial-based perfect absorber for electromagnetic energy harvesting applications

A compact-sized four-band metamaterial-based perfect absorber for electromagnetic energy harvesting applications

Power Analysis of Toroidal Core Electromagnetic Energy Harvesters for Transmission Lines

Introduction. As the need for energy increases, energy harvesting methods have also been intensively researched. Energy harvesting techniques which are a way of converting low amounts of energy from the environment into electrical energy can be used to meet the energy needs of low-power electronic devices and sensors. The increase in such sensors and devices with low power consumption also makes energy harvesting techniques more important. One of these harvesting techniques is energy harvesting from electromagnetic fields, which is obtained from transmission lines. Aim of the Article. The article is aimed at developing an effective electromagnetic energy harvester from energy transmission lines for unmanned aerial vehicles. Materials and Methods. The method of harvesting energy from transmission lines through magnetic field energy harvesting is reviewed. Theoretical analyses, Finite Element Analyses (FEA), and experimental studies are conducted on toroidal core structures designed in different sizes and with different materials. Results. Among the selected materials and under the specified line conditions, current of 0‒30 A and a frequency of 50 Hz, the highest power of 695.516 mW was harvested by the 60x30x20 sized ferrite core harvester at a line current of 30 A. Discussion and Conclusion. Detailed experiments were conducted based on the 60x30x20 mm ferrite core, which demonstrated the highest induced voltage. Different load resistances were used to find the resistance value for the highest power at each current value. The optimal load resistance for maximum power transmission was determined for each core using the curve fitting method at all current values.

Metamaterial Wave Absorber for Harvesting Electromagnetic Energy with Dispersion Characteristics Using Palm Oil Frond Graphitic Carbon

Metamaterial Wave Absorber for Harvesting Electromagnetic Energy with Dispersion Characteristics Using Palm Oil Frond Graphitic Carbon

Structural Performance and Evaluation of PDMS-Based Planar Membrane for Electromagnetic Vibration Energy Harvester (EM-VEH)

This paper discusses the performances of Polydimethylsiloxane (PDMS) membranes with the electromagnetic coils and magnetic arrangement as the supporting structure to generate electricity by capturing the energy from vibrating ambient source. The membrane attached to the permanent magnet moved according to the structure of the electromagnetic system. The study first designed the PDMS planar membrane to allow the vibration energy capturer to induce the coils efficiently. Membrane vibration from a loudspeaker with an operating frequency of 32 Hz was used as the vibration source. The generated energy stored in a storage circuit using a 220 µF/25 Volt capacitor, while a 1.5 Volt LED was used as a tested load in the system. The results showed that the moving membrane attached with a 10 mm diameter magnet revealed an open circuit output voltage of 500 mV on the EM coil. An experiment within a 20-minute flashing LED load test produced an output voltage of 2.2 Volts. This study would benefit the development of vibration energy harvester used to supply a low electrical power for microdevices in an isolated area.

A novel elastic strip suspension-based bi-directional electromagnetic wind energy harvester designed specifically for wind energy factories

In this study, we propose a novel parallel elastic strips suspended electromagnetic wind energy harvester (ESWEH) based on wind-induced vibration. Profiting galloping phenomena caused by wind flow, the hollow square tube is conceived to generate a significant transverse vibration, and two magnets are equipped on the hollow square tube to generate electrical energy utilizing the electromagnetic induction principle. The symmetrical design of the ESWEH enables it to harvest bi-directional wind energy, while this structure is easy to be assembled into an integrated energy harvesting factory to meet various power supply requirement. A theoretical model is developed to explain the operational mechanism of the proposed electromechanical coupling system. Further, a series of experiments are conducted in a wind tunnel to examine its power generation characteristics (including power-resistance, voltage-resistance) under a closed-circuit condition. The results of the experiments indicate that, when the wind velocity exceeds 2 m/s, the ESWEH equipped with both front and back attached fins produces a continuous and stable current output, with a voltage value exceeding 2.0 V and power exceeding 2.0 mW. Moreover, at an incoming wind velocity of 4 m/s, anaverage power of 7.8 mW is obtained, accompanied by a Root Mean Square (RMS) voltage of 3.2 V when connected to a resistance of 1.2 kΩ. In conclusion, the proposed ESWEH shows good performances in various aspects such as a simplified structure, efficiency-cost, low critical wind velocity and a high-power capacity. The experimental results further indicate that the proposed structure has potential application in construction of a stable power supplying system and wind energy factory for wireless sensors.

High-efficiency electromagnetic energy harvesting using double-elliptical metasurface resonators.

This study introduces a metasurface (MS) based electrically small resonator for ambient electromagnetic (EM) energy harvesting. It is an array of novel resonators comprising double-elliptical cylinders. The harvester's input impedance is designed to match free space, allowing incident EM power to be efficiently absorbed and then maximally channelled to a single load through optimally positioned vias. Unlike the previous research works where each array resonator was connected to a single load, in this work, the received power by all array resonators is channelled to a single load maximizing the power efficiency. The performance of the MS unit cell, when treated as an infinite structure, is examined concerning its absorption and harvesting efficiency. The numerical results demonstrate that the MS unit cell can absorb EM power, with near-perfect absorption of 90% in the frequency range of 5.14 GHz to 5.5 GHz under normal incidence and with a fractional bandwidth of 21%. The MS unit cell also achieves higher harvesting efficiency at various incident angles up to 60o. The design and analysis of an array of 4x4 double elliptical cylinder MS resonators integrated with a corporate feed network are also presented. The corporate feed network connects all the array elements to a single load, maximizing harvesting efficiency. The simulation and measurement results reveal an overall radiation to AC efficiency of about 90%, making it a prime candidate for energy harvesting applications.

An electromagnetic vibration energy harvester with compact flexure guide for low frequency applications

This paper presents the design, modeling, fabrication, and characterization of a novel electromagnetic vibration energy harvester (EVEH) using a compact flexure guide structure and opposing permanent magnets. The flexure guide is a unique cylindrical structure, and can transfer force and motion by the deformation of elastic beams. It allows the single-degree-of-freedom motion characteristic, and eliminates the friction between the permanent magnets and the housing structure, which exists in mostly reported magnet-spring based vibration energy harvesters. The structure also greatly reduces the spacing between the coil and the permanent magnets, which considerably increases the magnetic flux linkage through the coil. Experimental results show that the EVEH prototype can generate an output voltage of 6.08 V and output power of 4.02 mW from 0.1 g acceleration at resonant (19.5 Hz), achieving a normalized power density of 3.28 mW cm − 3g − 2. In addition, the flexure guide can be directly fabricated by 3D printing, which greatly simplifies the harvester assembly compared to other EVEHs reported. In terms of the proposed EVEH, a self-powered sensor network is implemented to transfer the GPS data to some appointed terminals.