Electromagnetic Energy Harvester Research Articles

Electromagnetic vibrational energy harvester with targeted frequency-tuning capability based on magnetic levitation

Electromagnetic vibrational energy harvester with targeted frequency-tuning capability based on magnetic levitation

A viscoelastic nonlinear energy sink with an electromagnetic energy harvester: Narrow-band random response

Abstract Nonlinear energy sink is a passive energy absorption device that surpasses linear dampers, and has gained significant attention in various fields of vibration suppression. This is owing to its capacity to offer high vibration attenuation and robustness across a wide frequency spectrum. Energy harvester is a device employed to convert kinetic energy into usable electric energy. In this paper, we propose an electromagnetic energy harvester enhanced viscoelastic nonlinear energy sink (VNES) to achieve passive vibration suppression and energy harvesting simultaneously. A critical departure from prior studies is the investigation of the stochastic P-bifurcation of the electromechanically coupled VNES system under narrow-band random excitation. Initially, approximate analytical solutions are derived using a combination of multiple-scale method and a perturbation approach. The substantial agreement between theoretical analysis solutions and numerical solutions obtained from Monte Carlo simulation underscores the method’s high degree of validity. Furthermore, the effects of system parameters on system responses are carefully examined. Additionally, we demonstrate that stochastic P-bifurcation can be induced by system parameters, which is further verified by the steady-state density functions of displacement. Lastly, we analyze the impacts of various parameters on mean square current and mean output power, crucial for selecting suitable parameters to enhance energy harvesting performance.

Effect of eccentric mass on rotor dynamics as a source of harvesting energy vibration

This research focuses on the potential for vibration energy from the use of eccentric masses in dynamic rotors to become an electrical energy source. Prior studies on eccentric mass in dynamic rotors were primarily concerned with examining the rotor's vibrational characteristics; however, little research was done on converting vibrational energy into electrical energy. The purpose of this study is to ascertain the maximum amount of electrical energy that can be produced by dynamic rotor vibrations using an eccentric mass. Utilizing an electromagnetic energy harvester, an experimental study is the methodology used. With a rotor rotation speed of 450 rpm, the eccentric mass variations used are 6.5 grams, 8.5 grams, and 10.5 grams. Matlab is used in this research to process data. The highest energy, using an eccentric mass of 8.5 grams, was found to be 24.15 mV. Nevertheless, this study shows that while the eccentric mass has an impact on the amplitude, it has no effect on the voltage. In order to increase and improve the efficiency of the electrical energy produced, further research on the utilization of vibration energy from dynamic rotors can be guided by the findings of this study

Harvesting energy vibration derived from the rotational speed of a A 4-stroke engine

The utilization of vibration energy from a 4-stroke engine as a potential source of electrical energy. Previous studies have focused on analyzing the vibration characteristics and frequency response functions of the 4-stroke engine, but there is a lack of research on harnessing vibration energy as a source of electrical energy. Therefore, this research aims to fill this gap by developing a system to harness the vibration energy from the 4-stroke engine, making it a primary focus of the study. The method employed is an experimental study involving data collection using an FFT Analyzer and Matlab. The research results indicate the presence of several mode shapes in the 4-stroke piston motor. The energy harvesting device utilized is of the electromagnetic type. However, the research reveals that the utilization of vibrations from the 4-stroke piston motor as a source of electrical energy is still not efficient and requires further development. There are various mode shapes in the 4-stroke piston motor at different rotational speeds, but the electromagnetic energy harvesting device used is unable to generate significant electrical energy. Therefore, this research provides a foundation for conducting further research in utilizing the vibrations of a 4-stroke piston motor as a more efficient source of electrical energy

Data-driven modeling and fast adjustment for digital coded metasurfaces database: Application in adaptive electromagnetic energy harvesting

Metasurfaces (MSs) show great promise in efficient electromagnetic energy harvesting (EMEH) due to their compactness, high efficiency, and long-distance transmission capabilities. Nonetheless, the conventional iterative and time-consuming solving process of MSs significantly escalates computational demands. Furthermore, once processed, the MS shape remains fixed and cannot be adapted to changing requirements. Accordingly, a critical challenge is the development of a new efficient solver for MS real-time tuning. Here, we introduce a class of digital coded MS databases including multiple pre-defined resonant frequency MS. The combination of multiple MS base functions from the database enables swift resonance frequency adjustments to adapt to changing environmental conditions. A topology optimization method based on data-driven modeling is employed to rapidly acquire the optimal digital coding for the corresponding MS at various operating frequencies, facilitating the construction of a database. This approach integrates a convolutional neural network and genetic algorithm (CNNGA). It not only enables more accurate and expedited forward prediction of MSs' electromagnetic (EM) response but also facilitates inverse design based on specified requirements. We employ this method to design a MS that achieves perfect energy harvesting (EH) over a broad range of incident angles and polarization directions. In addition, a data-driven modeling is used to establish an EH efficiency predictive model corresponding to MS combination. This model serves as a guide for real-time MS adjustments as per changing requirements. Compared to previously designed MSs, this model achieves rapid design and adaptive adjustment capabilities. Through the incorporation of various functional MS base functions into the database, this method can be universally applied to MS combinations tailored to specific functions, including EM cloaking, ultra-thin flat lenses, and computational MSs.

A high-performance electromagnetic energy harvester for scavenging ultra-low frequency vibration energy of human foot movement

A high-performance electromagnetic energy harvester for scavenging ultra-low frequency vibration energy of human foot movement

Scalable electromagnetic energy harvester for wind turbine rotor blade applications

One of the biggest challenges in structural health monitoring for rotor blades in wind turbines is to provide enough energy to power wireless sensor nodes. Batteries are not an adequate solution due to their limited lifetime and conventional cabling fails due to the rotation of the rotor blade. Therefore, we present an electromagnetic energy harvester that is specifically designed to be operated inside rotor blades and can generate a sufficient amount of energy. It uses the changing gravitational force vector to move a permanent magnet in a tube and converts this mechanical into electrical energy by coils arranged around the tube. Finite element methods simulations were performed to estimate the generated energy and an extensive parameter sweep of several key design parameters provided guidance for an optimized performance of a prototype. This device was characterized in the lab followed by a field test in a wind turbine where it was operated for several days and provided a continuous and rectified power of 6 mW, enough to power conventional wireless accelerometers, typically used within a predictive maintenance concept for the vibrational monitoring of rotor blades.

Energy Harvester Based on a Rotational Pendulum Supported with FEM

The proposed energy harvesting system is based on a rotational pendulum-like electromagnetic device. Pendulum energy harvesting systems can be used to generate power for wearable devices such as smart watches and fitness trackers, by harnessing the energy from the human body motion. These systems can also be used to power low-energy-consuming sensors and monitoring devices in industrial settings where consistent ambient vibrations are present, enabling continuous operation without any need for frequent battery replacements. The pendulum-based energy harvester presented in this work was equipped with additional adjustable permanent magnets placed inside the induction coils, governing the movement of the pendulum. This research pioneers a novel electromagnetic energy harvester design that offers customizable potential configurations. Such a design was realized using the 3D printing method for enhanced precision, and analyzed using the finite element method (FEM). The reduced dynamic model was derived for a real-size device and FEM-based simulations were carried out to estimate the distribution and interaction of the magnetic field. Dynamic simulations were performed for the selected magnet configurations of the system. Power output analyses are presented for systems with and without the additional magnets inside the coils. The primary outcome of this research demonstrates the importance of optimization of geometric configuration. Such an optimization was exercised here by strategically choosing the size and positioning of the magnets, which significantly enhanced energy harvesting performance by facilitating easier passage of the pendulum through magnetic barriers.

Electromagnetic Energy Harvester Targeting Wearable and Biomedical Applications.

This work presents a miniaturized electromagnetic energy harvester (EMEH) based on two coils moving in a head-to-head permanent magnet tower. The two coils are separated by a set distance so that the applied force moves the EMEH from one equilibrium position to another. In this configuration, the harvester produces energy in two different working modes: when a force is applied to the moving part or when an external random acceleration is applied to the whole system. A custom test bench has been designed to characterize the behavior of this energy harvester under a variety of conditions encountered in wearable applications. Notably, at 10 Hz and 1.32 g RMS acceleration, our inertial EMEH demonstrates its capability to sustain a consistent output power of 1696 μW within a total volume of 22.39 cm3, showcasing its efficiency in environments with erratic stimuli typical of wearable and biomedical applications. The presented EMEH is compared with reported inertial EMEH structures to extract its design limitations as well as future improvements, situating the present work in a comprehensive state-of-the-art and defining a generic performance target for biomedical and wearable applications.

Single body-coupled fiber enables chipless textile electronics.

Intelligent textiles provide an ideal platform for merging technology into daily routines. However, current textile electronic systems often rely on rigid silicon components, which limits seamless integration, energy efficiency, and comfort. Chipless electronic systems still face digital logic challenges owing to the lack of dynamic energy-switching carriers. We propose a chipless body-coupled energy interaction mechanism for ambient electromagnetic energy harvesting and wireless signal transmission through a single fiber. The fiber itself enables wireless visual-digital interactions without the need for extra chips or batteries on textiles. Because all of the electronic assemblies are merged in a miniature fiber, this facilitates scalable fabrication and compatibility with modern weaving techniques, thereby enabling versatile and intelligent clothing. We propose a strategy that may address the problems of silicon-based textile systems.

Mathematical Analysis of the Electromotive Induced Force in a Magnetically Damped Suspension

This study explores the advanced mathematical modeling of electromagnetic energy harvesting in vehicle suspension systems, addressing the pressing need for sustainable transportation and improved energy efficiency. We focus on the complex challenge posed by the non-linear behavior of magnetic flux in relation to displacement, a critical aspect often overlooked in conventional approaches. Utilizing Taylor expansion and Fourier analysis, we dissect the intricate relationship between oscillation and electromagnetic damping, crucial for optimizing energy recovery. Our rigorous mathematical methodology enables the precise calculation of the average power per cycle and unit mass, providing a robust metric for evaluating the effectiveness of energy harvesting. Further, the study extends to the practical application in a combined system of passive and electromagnetic suspension, demonstrating the real-world viability of our theoretical findings. This research not only offers a comprehensive solution for enhancing vehicle efficiency through advanced suspension systems but also sets a precedent for the integration of complex mathematical techniques in solving real-world engineering challenges, contributing significantly to the future of energy-efficient automotive technologies. The cases reviewed in this article and listed as references are those commonly found in the literature.

A Triboelectric-Piezoelectric-Electromagnetic hybrid wind energy harvester based on a snap-through bistable mechanism

Real-time monitoring is essential for safeguarding infrastructure in extreme environments, particularly in remote areas with abundant wind resources where sustained strong winds are common. A triboelectric-piezoelectric-electromagnetic hybrid wind energy harvester based on a snap-through bistable mechanism (ST-HWEH) is proposed, which can be used as a sustainable power source and a self-powered wind speed sensor. The piezoelectric energy harvester (PEH), triboelectric nanogenerator (TENG), and electromagnetic energy harvester (EMH) are placed at the maximum strain location, maximum contact area, and maximum displacement position of the bistable buckled beam, respectively, fully utilizing its characteristics in the structural space. The bistable buckled beam undergoes convex and concave snap-through transformations under the magnetic excitation, working synergistically with the buckled boundary to simultaneously achieve the three electromechanical energy conversions, thereby enhancing the electrical output performance of the system. Moreover, both the starting wind speed and resistance torque of the system are effectively reduced through the arrangement of symmetrical excited magnets with antimagnetic poles on the buckled beam. A prototype is prepared and subsequently experimentally verified. The results show that the overall output power density in a composite power generation unit for the ST-HWEH is 83.97 W/m3 at a wind speed of 11 m/s, which is 6.88 times higher than that of the ST-HWEH that only contains TENG. The prototype can easily light up 1000 LED lights at a mild wind speed of 5 m/s and demonstrate self-powered environmental monitoring (taking temperature and wind speed as examples), providing a potential solution for self-powered environmental monitoring and status monitoring of the infrastructure.

Wideband metasurface-loaded rectenna for azimuth-insensitive electromagnetic energy absorption using characteristic mode analysis

In this paper, a wideband metasurface-loaded (MTS-L) rectenna system is proposed to capture electromagnetic (EM) energy at arbitrary azimuth angles. The radiation patterns of different modes in the original MTS configuration are analyzed using the characteristic mode theory, and potential modes with omnidirectional radiation are screened out. By the arrangement of patches, the roundness performance of the radiation pattern can be ameliorated, and the omnidirectional characteristic is obtained over a wide frequency band. Subsequently, the surface current density of the selected mode is carefully and artificially designed to facilitate probe excitation as well as refrain from introducing complex power-combining networks. A wideband rectifier circuit is designed as the load of the proposed antenna. Eventually, measured results show that it operates from 4.6 to 9.6 GHz with a fractional bandwidth of 70.4%, and the peak system efficiency is 52.2%. The proposed system demonstrates excellent potential for wireless power transmission and EM energy harvesting in indoor environments.

Designs of Energy Harvester for Wireless Sensor Networks

An essential part of the IoT architecture are wireless sensor networks. There has been extensive study done to identify alternative methods of powering wireless sensor networks because the nodes of wireless sensor networks are mostly power constrained. This study mainly introduces three energy collector solutions that can power wireless sensors. They are an electromagnetic vibration energy harvesting system that powers the light source of the fiber Bragg grating sensor, a solar energy collection system that uses ambient photovoltaic energy, and a wind energy harvester that uses gas elastic vibration to convert wind energy into electrical energy. The solar energy collection system is based on maximum power point tracking, in which the solar panels can provide 3W of power with a high efficiency of up to 96%; the wind energy harvester is composed of a wind generator and a power management unit, capable of operating at wind speeds of 2-9m/s, providing 70mW of power. Besides, the electromagnetic vibration energy harvesting system provides an average power output of approximately 40mW when subjected to acceleration levels greater than 0.05g. These results can serve as solutions for sustainable power output.

Compact dual-band metamaterial absorber: Enhancing electromagnetic energy harvesting with polarization-insensitive and wide-angle capabilities

A novel compact metamaterial (MM) energy harvester optimized for Wi-Fi frequencies (2.4 GHz and 5.8 GHz) is introduced in this study. The energy harvester exhibits polarization insensitivity and versatility across various incident angles. The energy harvesting (EH) efficiency is evaluated using numerical simulations and practical experiments. The design features ring and octagonal resonators constructed with Rogers RT 5880 Substrate, with each octagonal resonator incorporating a strategically placed gap for lumped elements. The structure's impedance is meticulously aligned with free space to efficiently absorb incident electromagnetic (EM) power with minimal reflection. The simulation outcomes indicate that normal incidence at 2.4 GHz and 5.8 GHz yields high-efficiency levels of 96 % and 98 %, respectively. To validate these results experimentally, we conducted tests in an anechoic chamber using a fabricated 3 × 3 array structure. The results showed a significant correlation between the simulation outcomes and experimental data. The proposed MM energy harvester is highly efficient and shows great promise as an alternative for various microwave applications, such as EH and wireless power transfer.

Automatic Impedance Matching With Dual Time-Scale P&O in Fully Self-Powered Electromagnetic Vibration Energy Harvesting

Automatic Impedance Matching With Dual Time-Scale P&O in Fully Self-Powered Electromagnetic Vibration Energy Harvesting

Kresling origami-inspired electromagnetic energy harvester with reversible nonlinearity

This paper presents an electromagnetic energy harvester based on a unique nonlinear Kresling origami-inspired structure. By introducing the equilibrium shift phenomenon, reversible nonlinearity (i.e. mixed softening-hardening behavior) empowers the proposed harvester to work in a broad frequency band, confirmed by both simulation using a dynamic model and experimentation. The prototyped device can produce the open-circuit root mean square (RMS) voltage from 0.09 V to 0.20 V in the reversibly nonlinear response region in (6.19 Hz, 9.63 Hz) and a maximum output power of 0.4956 mW at an optimum load of 18.1 Ω under the excitation of 1.1 g. Moreover, detailed research further reveals that the design parameters of Kresling origami-inspired structure and electrical and mechanical loads influence reversible nonlinearity. Increasing the tip mass and γ 0 in the M2 region of the design map strengthens the softening behavior, and enlarging the electrical load enhances the hardening behavior. The findings from this work deepen the understanding of the nonlinear behavior of Kresling origami, unveils the great potential of origami structure in energy harvesting and offers a new method to realize broadband vibration energy harvesters.

A Novel Tri-Magnet Levitating Bistable Electromagnetic Energy Harvester with Variable Potential Wells to Promote Snap-Through Behavior

To achieve broadband energy harvesting under weak excitations, this paper comprehensively investigates a novel tri-magnet levitating bistable electromagnetic energy harvester with variable potential wells (BEEH-VP). The bistable nonlinear mechanism is realized using the single-sided bipolarity of the ring magnets. Auxiliary springs are integrated into the ring magnets to dynamically self-adjust the spacing of the ring magnets, causing variable potential wells. The analytical model of BEEH-VP is derived and verified experimentally. The performance of the proposed BEEH-VP is compared with that of the bistable electromagnetic energy harvester with featuring fixed potential wells (BEEH-FP). The comparative results clearly demonstrate that the BEEH-VP exhibits superior capabilities in terms of energy output under weak excitation and possesses a broader frequency bandwidth. Bifurcation analysis for the excitation conditions reveals that the proposed structure features complex dynamic behaviors, such as intra-well, chaotic, harmonic inter-well and subharmonic inter-well vibrations. In comparison to BEEH-FP, BEEH-VP requires lower acceleration to perform the snap-through and has a larger vibration amplitude, facilitating improved output performance.

Performance analysis of electromagnetic vibration energy harvester under square excitation

Harvesting energy from surrounding vibrations is an effective method for powering various low-power electronic devices. The energy output performance of vibration energy harvesters under some special excitations remains to be investigated. In this paper, a vibration energy harvester (VEH) system based on a rack and pinion mechanism and a bevel gear set is proposed, and a detailed electromechanical coupling modeling of the system under general excitation and square wave excitation is carried out. The energy output characteristics of the proposed system under square wave excitation are explored through simulation and experiment. When the energy output is the target, the priority of adjusting the constituent parameters in the equivalent mass parameter, equivalent damping parameter and equivalent stiffness parameter of the system can be obtained based on the simulation results. The experimental results under periodic square wave excitation force show that the maximum output power of the proposed system is 2.7 W at an amplitude of 4 kN and a frequency of 3 Hz. This is a 55 % increase in the maximum power compared to the sinusoidal excitation under the same conditions. It is demonstrated that the proposed system has great potential to power various low-power electronic devices.

Microwave Metamaterial Absorber with Radio Frequency/Direct Current Converter for Electromagnetic Harvesting System

This article presents the analysis of the electromagnetic (EM) properties of a novel metamaterial (MM) array in the microwave frequency range. The background for this work is the rapid development of portable devices with low individual energy consumption for the so-called “Internet of Things” (IoT) and the demand for energy harvesting from the environment on a micro scale through harvesters capable of powering billions of small receivers globally. The main goal of this work was to check the potential of the novel MM array structure for EM energy harvesting. The proposed MM array was analyzed in the CST Studio simulation environment. This resulted in the determination of the substitute average EM parameters (absorption, reflection, and transmission) of the MM array. Then, the MM array was manufactured, and the simulation results of the MM array parameters were experimentally validated in a microwave waveguide test system. Based on this conclusion, a prototype of the microwave MM absorber, together with an RF/DC converter, was designed and manufactured for harvesting EM energy from the environment. The system’s energy efficiency was evaluated, and its potential application in energy harvesting technology was appraised. Using a microwave horn antenna, the EM energy harvesting efficiency of the prototype was evaluated. It was about 50% at a microwave frequency of about 2.6 GHz. This may make the prototype attractive as an EM energy harvester or bolometric sensor.