Electromagnetic Energy Harvesting System Research Articles

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.

Footstep-powered floor tile: Design and evaluation of an electromagnetic frequency up-converted energy harvesting system enhanced by a cylindrical Halbach array

Energy harvesting floor systems use the mechanical energy generated by human weight to produce electrical energy, providing sustainable power sources for low-power systems at pedestrian crossings. They also have the potential to serve as renewable energy solutions on a larger scale. This study evaluates the design and performance of a kinetic energy harvester floor tile. The system design employs a frequency up-conversion technique to utilize the force exerted by the weight of humans for creating vibrational movement. In addition, the use of the cylindrical Halbach array improves the magnetic flux gradient, leading to an increased power output. A semi-analytical model is presented to evaluate the system performance, which is then validated through available experimental analysis and finite element simulations. A sensitivity analysis is performed to assess the impact of various factors on system performance, ultimately determining the optimal configuration. The optimal modular system is then used to create a 30 × 30 cm2 tile. This tile is capable of generating energy while walking, running, jogging, slow running, and fast running, with power outputs of 0.57, 0.85, 1.11, and 1.42 W (0.57, 0.86, 1.11, and 1.58 mW/cm2) respectively. Additionally, it is estimated that 511 mJ (568 mJ/cm2) of energy is generated per step. Additionally, an assessment is conducted on the energy production capabilities and environmental advantages of a specific site, such as a subway station.

An electromagnetic vibration energy harvesting system based on series coupling input mechanism for freight railroads

Vibration energy harvesting technology is characterized by wide distribution, is pollution-free and independent of weather and climate, and is suitable for powering low-power sensors to ensure efficient and safe operation in freight railroads. This paper proposed an electromagnetic vibration energy harvester based on a series coupling input mechanism for the self-powered sensors in freight railroads. The design utilizes only one rack for vibration energy input to minimize the moment acting on the vibration source during the working process. Two pinions meshed with the rack convert the up and down vibrations into a two-way rotation. The one-way bearings and another pair of gears convert the opposite rotations of two parallel shafts into one-way rotation of the generator shaft, generating electricity. Supercapacitors and rectifier voltage regulator modules are utilized to store electrical energy efficiently. A peak power of 10.219 W and maximum mechanical efficiency of 64.31% is obtained in the experiment equipped with a flywheel under the 8 mm-4 Hz sinusoidal vibration excitation. The experimental results showed that the flywheel can enable the proposed harvester to achieve better power generation performance when the amplitude and frequency are relatively high.

Development of an Electromagnetic Energy Harvesting System Based on a Current Transformer for Use in Industrial Electric Motors

Development of an Electromagnetic Energy Harvesting System Based on a Current Transformer for Use in Industrial Electric Motors

Dynamic responses of an energy harvesting system based on piezoelectric and electromagnetic mechanisms under colored noise

Because of the increasing demand for electrical energy, vibration energy harvesters (VEHs) that convert vibratory energy into electrical energy are a promising technology. In order to improve the efficiency of harvesting energy from environmental vibration, here we investigate a hybrid VEH. Unlike previous studies, this article analyzes the stochastic responses of the hybrid piezoelectric and electromagnetic energy harvesting system with viscoelastic material under narrow-band (colored) noise. Firstly, a mass-spring-damping system model coupled with piezoelectric and electromagnetic circuits under fundamental acceleration excitation is established, and analytical solutions to the dimensionless equations are derived. Then, the formula of the amplitude-frequency responses in the deterministic case and the first-order and second-order steady-state moments of the amplitude in the stochastic case are obtained by using the multi-scales method. The amplitude-frequency analytical solutions are in good agreement with the numerical solutions obtained by the Monte Carlo method. Furthermore, the stochastic bifurcation diagram is plotted for the first-order steady-state moment of the amplitude with respect to the detuning frequency and viscoelastic parameter. Eventually, the influence of system parameters on mean-square electric voltage, mean-square electric current and mean output power is discussed. Results show that the electromechanical coupling coefficients, random excitation and viscoelastic parameter have a positive effect on the output power of the system.

Development of an Autonomous Magnetic Permeability Sensor

In our days, there is an undeniable need for control over the quality of metals in machines, metal components, tools, and construction materials during production and maintenance. Nondestructive testing sensors have been proven to be the most effective way of determining the quality of the composition of materials since they can detect flaws, not only during their construction but also during maintenance, without interfering with, or obstructing, their use. This article focuses on the measurement of the magnetic permeability of ferromagnetic steels and alloys as a nondestructive method of correlating magnetic properties with residual stresses based on the use of a yoke-shaped sensor. Most importantly, an electromagnetic energy harvesting system has been designed and tested, based on the exploitation of mechanical vibrations. The combination of the sensor and the energy harvesting system can lead to an energy autonomous device, which can be placed in inaccessible locations for remote nondestructive testing where measurements can be taken and transmitted autonomously every 10 min. Said transmission is realized by a network of yoke sensors in multiplex configuration and sent to a central sensor, leading to an Internet of Things usable device.

Investigation Into the Effect of Joint Clearance on the Dynamics of a Biomechanical Energy Harvesting System

The existing clearance in the mechanical joints plays a crucial role in the assembly of mechanical systems, allowing the mobility of its components. However, few studies have explored models that consider joint clearance in the case of electromechanical energy harvesting systems. This paper examines the effect of existing clearance in an electromagnetic energy harvester attached to the human lower limb. The dynamic response of the system and an estimate of its generated power are obtained by developing a lumped model, in which clearance is included by adding a dead band and assigning a stiffness coefficient during contact between elements. The natural motion of the lower limb is the input to the formulated model, which takes into account the nonlinear interaction of the electromagnetic device and the power conditioning circuit. Central composite design is used to study the influence of two selected factors on the dynamics of the system; joint clearance size and contact stiffness. The results suggest that the presence of clearance between the clamping mechanism and the human body positively affects the performance of the analyzed electromagnetic energy harvesting system. It was revealed that an increase of around 27% of output power could be intentionally achieved by adding larger clearance sizes.

A self-adapting wind energy harvesting system for application in canyon bridge

Many countries have increasingly built canyon bridges to develop road-based traffic in uneven terrain. Mostly, these bridges are installed far from residential areas where electricity supply is challenging. The health monitoring of these bridges is the most critical concern and gained extensive attention for safe operation with longevity. In order to solve the power supply problem of the canyon bridge health monitoring system (HMS), an adaptive electromagnetic induction-based wind energy harvesting system is proposed. The wind energy harvesting system can help to attain a zero-energy canyon bridge health monitoring system without external cables and chemical batteries. The wind energy harvesting system captures the natural wind and the wind generated by the passing vehicles. The adaptive power generation module adjusts the current most suitable electromagnetic induction mode according to the wind speed and generates electrical energy. The energy storage module rectifies the electric energy and stores it in the supercapacitor to power the health monitoring system of the bridge. The feasibility of the proposed system is analyzed by simulating the coupling effect of mixed wind fields and the electromagnetic characteristics of the double-layer disc generator. Finally, experiments show that a single wind turbine can generate a power of 471.56mW at the wind speed is 14 m/s.

Fully Self-Powered Inductor-Less Electromagnetic Vibration Energy Harvesting System Using Auxiliary Coils for Hysteresis Current MPPT Control

Utilizing coil inductor of electromagnetic vibration energy harvester (EVEH) to form single stage ac–dc boost converter can make the self-powered milli-power system more compact. However, large output current harmonics of EVEH significantly degraded the output power in such system. This article proposes a new approach of adopting hysteresis current control to realize maximum power point tracking (MPPT) and reduce current harmonics in inductor-less converter by using auxiliary coils. The output characteristics and correlations between multiple coils are firstly studied to verify the feasibility of using auxiliary coil to represent the output of main coil. The optimal winding strategy for main coil and auxiliary coils is revealed for no degradation on maximum output power of main coil. Based upon these, a completely self-powered multicoil EVEH system is designed with auxiliary coils as reference for MPPT controller and as auxiliary power supply in cold-start. Experiments show that the designed prototype can obtain 9.54 mW output power at acceleration of 3 m/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , with the overall efficiency of 77.6%. To charge a 10 mF supercapacitor from zero to 5 V, an average output power of 7.27 mW can be obtained with an average charging efficiency of 62.4%. In addition, the start-up method adopting auxiliary coil allows the system to cold-start when the output voltage is lower as 0.5 V. The proposed approach has been demonstrated to achieve high overall efficiency in milli-power self-powered EVEH system and also has significant advantages in cost and volume compared with using external devices to obtain reference.

Design of vibro-impact electromagnetic ocean-wave energy harvesting system; an experimental study

Ocean wave energy is a stable renewable energy source, which has realistic application prospects. Based on the intermittent and irregular nature of ocean-wave, researchers have designed many ocean-wave energy harvesters, with several advantages and disadvantages. The main goal of this study is to present a new ocean wave energy harvester, which works based on the small pitch motion of moving floaters. Unlike almost all the previously presented systems, the presented ocean wave energy harvester can work in moving forward ships and boats like emergency boats. To do so, a ibro-impact system is designed to gather the kinetic energy of small pitch motions and transmit it to the vibratory part of the system via impulsive load. A mechanical rectifier that gets its input energy from the oscillations of the vibratory part, provides continuous rotations needed by the electromagnetic transducer. The governing electromechanical equation of motion for the discussed system is derived to study the effects of changing the ocean-wave properties on the application of the energy harvester. It is shown the gap size of the impact part of the system and the ocean-wave period have important effects on the output electrical energy.

A Magnet-Coil-Type Bistable Vibration Energy Harvester for Random Wave Environment

In this study, a new bistable vibration energy harvesting system is developed by originally proposing a bistable vibration model comprising a spring and a mass block and then applying a vibration generator composed of a coil and a magnet. The nonlinear equations of motion for this vibration energy harvesting system are developed and the static potential energy distribution is analyzed. The bistable vibration characteristics and the method for prediction of the periodic excitation frequency at which stochastic resonance is likely to occur are investigated theoretically, and the electromagnetic induction-based bistable vibration energy harvesting system is then developed. We predicted the excitation value that the stochastic resonance phenomenon is most likely to occur at 1.543 Hz. We also conducted experiments at 1.15 Hz, 1.50 Hz, and 1.85 Hz, which are centered on the predicted value. As a result, stochastic resonance occurred in all experimental cases. The power generation efficiency was improved by 125.03%, 149.05%, and 95.39%, respectively.

Three-Port Power Electronic Interface With Decoupled Voltage Regulation and MPPT in Electromagnetic Energy Harvesting Systems

In conventional electromagnetic energy harvesting systems, a two-port ac&#x2013;dc rectifier is utilized to process the harvested power. However, it is difficult to achieve voltage regulation and maximum-power-point-tracking (MPPT) simultaneously. To resolve this issue, this article proposes a three-port power-electronic-interface (PEI) dedicated to this application. A battery port is introduced to buffer the redundant energy. A bidirectional dc&#x2013;dc converter is utilized to tightly regulate the load side voltage. To capture the maximum power for the harvester, a simple MPPT method is proposed for this PEI. The power tracking of ac source can be simplified by dealing with the power of the battery port. The regulations of power and output voltage are fully decoupled with different control degree-of-freedoms. Moreover, when the harvester is in idle mode, the load can be powered by the battery via the bidirectional dc&#x2013;dc converter independently. A 24-mW rated laboratory prototype, which processes the power flow among a 0.6 V, 100 Hz ac source, a 1.2 V battery, and a 3.3 V constant voltage load is developed and tested. The proposed concept is validated by experimental results.

A Halbach cylinder-based system for energy harvesting from rotational motion with high power density

This paper presents an electromagnetic energy harvesting system based on a Halbach array (HA) optimized to improve the volume power density. The system design is based on a Halbach cylinder that emphasizes the magnetic field towards its center. 16 magnets are arranged in the middle along the generatrix of the cylindrical housing, while four serially connected coils are attached to the axis and oriented radially. When mechanically excited, the cylindrical housing rotates around the coils, which allows the generation of a sinusoidally induced voltage. A finite element analysis approach was first presented for different magnet numbers, and the magnetic flux was found for different coil radiuses. Then a 3D-printed prototype was fabricated and tested at a rotating speed of 5700 rpm. We first compared the device performance with and without HA. We measured an induced RMS voltage of 1.71 V and 1.27 V, respectively, which attests to the improvement brought by the HA. The final device, using four coils, achieved an RMS voltage of 2.08 V and generated power of 170 mW, which resulted in a power density of about 9.27 mW/cm3.

Kinetic Electromagnetic Energy Harvester for Railway Applications-Development and Test with Wireless Sensor.

This paper deals with a development and lab testing of energy harvesting technology for autonomous sensing in railway applications. Moving trains are subjected to high levels of vibrations and rail deformations that could be converted via energy harvesting into useful electricity. Modern maintenance solutions of a rail trackside typically consist of a large number of integrated sensing systems, which greatly benefit from autonomous source of energy. Although the amount of energy provided by conventional energy harvesting devices is usually only around several milliwatts, it is sufficient as a source of electrical power for low power sensing devices. The main aim of this paper is to design and test a kinetic electromagnetic energy harvesting system that could use energy from a passing train to deliver sufficient electrical power for sensing nodes. Measured mechanical vibrations of regional and express trains were used in laboratory testing of the developed energy harvesting device with an integrated resistive load and wireless transmission system, and based on these tests the proposed technology shows a high potential for railway applications.

Hybrid energy harvesting system under the electromagnetic induced vibrations with non-rigid ground connection

A hybrid energy harvesting system has been presented in this study by vibrating a beam element with an electromagnetic actuator. With the structure proposed in this article, two different types of energy harvesting concepts were provided with the piezoelectric patch attached to the fixed end of the cantilever beam and the electromagnetic device connected to the free end of the cantilever beam. Generally, in electromagnetic energy harvesting systems, the electromagnetic device is fixed from one end to the ground. The effects of vibration of this fixed surface on energy harvest are being neglected. Electromagnetic devices that provide energy harvesting and vibrate the beam element are of identical structure in the proposed hybrid system. Both devices are mounted at the same point of the beam to face each other. While one of these electromagnetic devices is fixed onto the ground, the other one is assembled to the main beam with a secondary parallel beam element. Therefore, the electromagnetic device that harvests energy or vibrates the beam element can be changed so that it can be either on the lower or upper side of the main beam element. With this designed structure, the behavior of electromagnetic energy harvesting elements and vibration actuators placed on the non-rigid ground has been investigated. Unlike conventional energy harvesting methods, the concept of displacement transmissibility has been discussed in this study. Experimental studies have performed the dynamic conditions to obtain optimum energy harvest in the proposed harvesting system for different frequency inputs. Experimental results revealed the effect of vibrations originating from the non-rigid ground on energy harvesting. It has been observed that the electromagnetic energy harvesting device connected to the non-rigid ground increases the amount of energy collected.

Metamaterial-Based Sub-Microwave Electromagnetic Field Energy Harvesting System

This paper presents the comprehensive analysis of the sub-microwave, radio frequency band resonant metastructures’ electromagnetic properties with a particular emphasis on the possibility of their application in energy harvesting systems. Selected structures based on representative topologies of metamaterials have been implemented in the simulation environment. The models have been analyzed and their substitute average electromagnetic parameters (absorption, reflection, transmission and homogenized permeability coefficients) have been determined. On the basis of simulation research, prototypes of electromagnetic field two-dimensional absorbers have been manufactured and verified experimentally in the proposed test system. The absorber has been implemented as a component of the low-cost energy harvesting system with a high-frequency rectifier and a voltage multiplier, obtaining usable DC energy from the electromagnetic field in certain frequency bands. The energy efficiency of the system has been determined and the potential application in energy harvesting technology has been assessed.

Modeling and Analysis of the Power Conditioning Circuit for an Electromagnetic Human Walking-Induced Energy Harvester

Among the various alternative energy sources, harvesting energy from the movement of the human body has emerged as a promising technology. The interaction between the energy harvesting structure and the power conditioning circuit is nonlinear in nature, which makes selecting the appropriate design parameters a complex task. In this work, we present an electromagnetic energy harvesting system suitable for recovering energy from the movement of the lower limb joints during walking. The system under study is modeled and simulated, considering three different scenarios in which the energy source is the hip, knee, and ankle joint. The power generated by the energy harvester is estimated from kinematic data collected from an experimental gait study on a selected participant. State-space representation and Recurrence plots (RPs) are used to study the dynamical system’s behavior resulting from the interaction between the electromagnetic structure and the power conditioning circuit. The maximum power obtained through the simulation considering a constant walking speed of 4.5 km/h lays in the range of 1.4 mW (ankle joint) to 90 mW (knee joint) without implementing a multiplier gear.

A novel mushroom lens antenna with wide beam using three dimensional printing

Lens is an effective antenna solution, the radiation pattern of the antenna can be enhanced through the dielectric lens, the lens antennas tend to be directive rather than omnidirectional that is. However, in this article, a monopole antenna integrated within a three dimensional printing mushroom shape lens and pasted the copper foil on the part of the surface of lens is proposed for wireless electromagnetic energy harvesting system at 5.8 GHz to the realization of a wide beam antenna. The bandwidth is from 5.33 to 6.07 GHz with the reflection coefficient below −10 dB. The half power beamwidth is 197° in x-z plane and 175° in y-z plane, respectively. And the peak gain is 2.47 dBi. Simulation results agree well with measured results.

Linear electromagnetic energy harvester system embedded on a vehicle suspension: From modeling to performance analysis

Although linear electromagnetic energy harvester (LEH) is a promising technique for converting energy in a vehicle suspension, due to the large displacements, one of the main drawbacks of the solutions inside the vehicle is still their size and complexity. To address this issue, this paper focuses on the design and fabrication of a fully embedded LEH without any modification of the suspension initial structure. After a determination of the electrical, mechanical and electromechanical parameters using a Finite Element analysis, the dynamic efficiency is highlighted with a global Bond Graph model. This formalism is well adapted to simulate energy transfers inside multiphysic systems and to reduce the computational time, whereas the finite element model is not exploitable for a complete suspension simulation. In order to validate the Bond Graph simulation results, an embedded prototype has been built and tested in a laboratory environment. The embedded LEH system delivers around 10 W for a solicitation of linear velocity of 1 m/s which is sufficient to power a classical electronic circuit which is in good correlation with the measured ones and significant power has been obtained.

Rail corrugation inspection by a self-contained triple-repellent electromagnetic energy harvesting system

Rail corrugation, a widely distributed periodic wear pattern of the railway track, is a severe rail defect that could cause high-pitched noises and vibrations of the ground and nearby buildings. The current rail corrugation inspection trolley can only be employed offline, whereas online monitoring devices require external batteries that depend heavily on manual maintenance. This paper presents a novel approach by monitoring the rail corrugation online using a self-contained energy harvesting system. The mechanics of the magnetic-floating energy harvester was improved by a triple-magnet configuration, and differences between repellent and attractive configurations were investigated. Comprehensive broad-band (5–2000 Hz) sinusoidal sweeping vibration tests and stochastic vibration tests were conducted based on the measured railway track spectra. The wavelet theory was used to carry out time–frequency analysis and identify the defects of the rail corrugation. The results indicate that the proposed system could collect the rail vibration energy across a wider frequency range as well as identify the rail corrugation by the induced voltage of the energy harvesters. This study offers a new sustainable approach toward rail corrugation monitoring by the self-contained energy harvesting system that could eliminate environmentally-unfriendly batteries and reduce manual involvement for railway track inspection.