Electromagnetic Vibration Energy Harvester Research Articles

A piezoelectric and electromagnetic vibration energy harvesting system based on spring pendulum structure and MPPT control

A piezoelectric and electromagnetic vibration energy harvesting system based on spring pendulum structure and MPPT control

Human-motion adaptability enhancement of wearable electromagnetic vibration energy harvesters toward self-sustained body sensor networks

Human-motion adaptability enhancement of wearable electromagnetic vibration energy harvesters toward self-sustained body sensor networks

Study of vibration suppression and energy harvesting for a Vibration-based Piezoelectric–Electromagnetic energy harvester with nonlinear energy sink

Vibration-based energy harvesting devices are prone to excessive displacement response. The effective vibration suppression is critical to the longevity and safety of energy harvesting systems. In this work, the vibration-based Piezoelectric–Electromagnetic energy harvester with nonlinear energy sink (NES-VBPEEH) is proposed to achieve the dual efficacy goals of vibration suppression and vibration energy harvesting. The electromechanical-coupled distributed governing equations are derived through Hamilton’s principle, Euler’s Bernoulli theory, Gauss’s law and Faraday’s law of electromagnetic induction. The output performances of the degradation model of the NES-VBPEEH are validated by previous work. Parameter analysis indicates that the external resistance of the piezoelectric energy harvester significantly affects the electrical damping of the system and ultimately affects the output response of the NES-VBPEEH. The external resistance and coil turns of the electromagnetic vibration energy harvester can significantly affect the output response of the NES-VBPEEH. The output power of both types of energy harvesters is maximized with respect to the resistance and the coil turns. The output response of the NES-VBPEEH exhibits certain nonlinear characteristics as the external excitation amplitude increases to a certain value. The damping and nonlinear stiffness of the NES can significantly affect the output power of the NES-VBPEEH, and appropriate parameter selection can help to achieve the dual efficacy goals of vibration suppression and vibration energy harvesting for the energy harvester.

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

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.

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

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.

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

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.

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.

Electromagnetic Wind-induced Vibration Energy Harvester with a Resonant Cavity

Wind energy, as the most widely distributed form of renewable energy, holds great significance in addressing the energy supply issue for micro-power electronic equipment. Therefore, this paper proposes an electromagnetic wind-induced vibration energy harvester with a resonant cavity (EWVEH). When the wind blows through the resonant cavity, the pressure inside the cavity increases, causing a change in the pressure distribution. The pressure on the lower surface of the elastic beam exceeds the pressure on the upper surface, leading to a pressure difference. When the pressure difference exceeds the damping force of the elastic beam, it will cause the beam to move, and then the vibration energy will be converted into electrical energy through electromagnetic conversion. The installation angle of the elastic beam and the size and position of the resonant cavity outlet will affect the fluid distribution in the resonant cavity and the vibration characteristics of the elastic beam. This, in turn, will change the output characteristics of the EWVEH. The simulation analysis and experimental research demonstrate that a smaller installation angle for the cantilever and a smaller outlet for the resonant cavity is advantageous for the EWVEH to obtain higher output power. Furthermore, the position of the air outlet also impacts the efficiency of the EWVEH. At a wind velocity of 14 m/s, the load voltage and power of the EWVEH are 39 mV and 101.4 μW, respectively.

A novel design of an array of pendulum-based electromagnetic broadband vibration energy harvester

This work investigates a novel design of an electromagnetic vibration energy harvester array based on pendulum structures under harmonic base excitation. The design includes combined magnetic-solenoid pendulum harvesters with different mechanical coupling configurations. A comparison is made with standalone magnetic and solenoid pendulum based harvester arrays under similar excitation conditions. Additionally, the positions of harvesters are shuffled and analyzed. The effects on harvested power, power density and frequency bandwidth are evaluated by considering dimensionless coupling ratios, damping ratios, mass ratios and length ratios as parameters. Further, the efficiency of the harvester against these parameters has also been reported. In addition, experimental validation of the numerical formulation is also conducted. The study shows that the proposed magnetic-solenoid harvester array can harvest sustained energy in a wider bandwidth compared to standalone magnetic and solenoid pendulum harvester arrays.

Research on electromagnetic vibration energy harvester for cloud-edge-end collaborative architecture in power grid

With the deepening of the construction of the new type power system, the grid has become increasingly complex, and its safe and stable operation is facing more challenges. In order to improve the quality and efficiency of power grid management, State Grid Corporation continues to promote the digital transformation of the grid, proposing concepts such as cloud-edge-end collaborative architecture and power Internet of Things, for which comprehensive sensing of the grid is an important foundation. Power equipment is widely distributed and has a wide variety of types, and online monitoring of them involves the deployment and application of a large number of power sensors. However, there are various problems in implementing active power supplies for these sensors, which restrict their service life. In order to collect and utilize the vibration energy widely present in the grid to provide power for sensors, this paper proposes an electromagnetic vibration energy harvester and its design methodology based on a four-straight-beam structure, and carries out a trial production of prototype. The vibration pickup unit of the harvester is composed of polyimide cantilevers, a permanent magnet and a mass-adjusting spacer. The mass-adjusting spacer can control the vibration frequency of the vibration unit to match the target frequency. In this paper, a key novel method is proposed to increase the number of turns in a limited volume by stacking flexible coils, which can boost the output voltage of the energy harvester. A test system is built to conduct a performance test for the prototype harvester. According to the test results, the resonant frequency of the device is 100 Hz, the output peak-to-peak voltage at the resonant frequency is 2.56 V at the acceleration of 1 g, and the maximum output power is around 151.7 mu W. The proposed four-straight-beam electromagnetic vibration energy harvester in this paper has obvious advantages in output voltage and power compared with state-of-the-art harvesters. It can provide sufficient power for various sensors, support the construction of cloud-edge-end architecture and the deployment of a massive number of power sensors. In the last part of this article, a self-powered transformer vibration monitor is presented, demonstrating the practicality of the proposed vibration energy harvester.

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.

High-density stacked microcoils integrated microminiaturized electromagnetic vibration energy harvester for self-powered acceleration sensing

High-density stacked microcoils integrated microminiaturized electromagnetic vibration energy harvester for self-powered acceleration sensing

Parameter optimization analysis of rotary electromagnetic vibration energy harvester for performance enhancement under free vibration

In this paper, three new important aspects of rotary electromagnetic vibration energy harvesting technology (RE-VEH) are concerned and investigated: (i)vibro-electric coupling mechanism of the RE-VEH system is studied through theoretical modeling; (ii) quantitative analysis of system parameters based on numerical simulation method is carried out for the optimal design of RE-VEH; and (iii) dynamic power output performance of the RE-VEH system in free vibration is discussed. The parameter adjusting methods of the RE-VEH system in free vibration mode are obtained through theoretical analysis and numerical simulation. The experimental results show that the power output performance of RE-VEH in free vibration mode matches the numerical simulation results. The simulation and experimental results show that the maximum voltage output and power output of the RE-VEH with different structure parameters under free vibration can be up to the level of 100∼101 V/watt. The above results indicate that RE-VEH in a free vibration environment has significant energy output performance.

Nonlinear energy harvesting from rotating system

A simple electromagnetic energy harvester with a cubic nonlinear stiffness is proposed and dynamic responses as well as the potential power harvested are studied in this paper. The proposed nonlinear electromagnetic vibration energy harvester can be installed on a host base that is rotating at a constant speed and vibrating vertically. Considering the combination of the vertically vibrating and rotating frequency of the host base, the 1:1 primary resonance is investigated by the method of multiple scales. The dynamic characteristics of responses in terms of system parameters are studied and bifurcation curves are constructed. In addition to possessing the resonance characteristics, some saddle–node bifurcations occur for the steady-state solutions under certain conditions. Moreover, the effects of system parameters on the output average power are investigated as well. The results of analysis show that multiple frequency bands and parameter regions exist where a large power can be harvested due to the nonlinear resonances. Introducing the nonlinearity not only can increase the power output but also expand the frequency bands and parameter regions to harvest more power. A carefully selected system parameters can help to optimize the average power harvested in the design.

Theoretical and experimental investigation of magnet and coil arrays optimization for power density improvement in electromagnetic vibration energy harvesters

Power density is a critical evaluation indicator of electromagnetic vibration energy harvesters and has become one of the research hotspots. Therefore, it is of great significance to establish a simple and accurate theory to optimize and guide the design of an energy harvester for power density enhancement. Indeed, an alternating magnet array has a high flux gradient, which is one of the key factors for power enhancement. Under volume constraints, the coil output power is highly related to the magnet configuration, as the latter determines the magnitude of the flux gradient as well as the total flux mutation. Motivated by this, in this paper, an electromagnetic vibration energy harvester based on a coil array and a magnet array is proposed. The magnetic field distribution of rectangular magnets is analyzed. Then, a theoretical model based on Faraday's law of electromagnetic induction is derived to efficiently calculate the open-circuit voltage of coils with different numbers of magnets. After that, the optimal magnetic configuration is obtained based on the developed model without the need of measuring the parasitic damping of the energy harvester. Simulations and experiments verify the correctness of the theory. The results show that at an acceleration of 1 g and frequency of 41.2 Hz, the output power and power density reach a maximum of 3.71 mW and 106.68 μW/cm3, respectively, when the number of magnets m = 6, which is 2.58 times higher than the case of m = 3 and 2.06 times higher than the case of m = 12. The model proposed in this paper applies to the optimization of magnet array configurations of any volume, demonstrating the great benefits of power density enhancement.

A nonlinear electromagnetic vibration energy harvester lubricated by magnetic fluid for low-frequency vibration

Using vibration energy harvesters (VEHs) to achieve self-power is an effective method to ensure long-term use of sensor networks. This paper proposes a nonlinear electromagnetic VEH lubricated by magnetic fluid (MF) for low-frequency vibration energy harvesting. The VEH uses fixed small magnets to reduce natural frequency and prevent moving a magnet stack from flipping, MF for lubrication to improve output voltage under weak vibration, and elastomers to prevent magnet damage under strong vibration. In addition, MF and elastomers can increase the nonlinearity of restoring force, broadening the response frequency of VEHs. The motion state of the VEH is analyzed, and a crank-slider mechanism is used to test the output performance of VEHs. The influence of shell conductivity, the number of fixed small magnets, and length of VEH on output voltage is studied, and the results show that the VEH with an insulated shell, fewer fixed small magnets, and suitable length generates higher output voltage. The MF mainly plays a damping role in strong vibration but mainly plays a lubricating role in weak vibration. For experiments with 15 mm amplitude at 7.9 Hz, the output power density of the VEH without MF and lubricated by MF are 2.436 and 1.862 mW/cm3, respectively. MF damping reduces the output power density by 23.56%. However, for experiments with 7.5 mm amplitude at 3 Hz, the output power for VEHs without MF and lubricated by MF are 0.065 and 0.254 mW, respectively. The output power is increased by 291% with MF lubrication.