Harnessing Kinetic Energy From Human Motions With a High-Efficiency Wearable Electromagnetic Energy Harvester

2020 ◽  
Author(s):  
Yan Peng ◽  
Dong Zhang ◽  
Jun Luo ◽  
Shaorong Xie ◽  
Huayan Pu ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Flux Density ◽  
Energy Harvester ◽  
High Efficiency ◽  
Experimental Studies ◽  
Electromagnetic Energy ◽  
Maximum Output ◽  
Excellent Performance ◽  
Mass System ◽  
Current Output

Abstract Recent years have witnessed explosive increase in the number of wearable devices in the market and industry. However, hardly have these devices gained the ability to capture energy from hosts and then get self-charged. In this paper, we design and build a novel wearable electromagnetic energy harvester to scavenge the kinetic energy of human ankle during walking or running. The design is composed of mainly three parts: a spring-mass system, rolling ball pair and the electromagnetic transduction mechanism. The harvester adopts an array of alternating south- and north-pole magnets. This arrangement allows the array exhibits a unique phenomenon, i.e. abrupt magnetic flux density changes within the array. Because of this phenomenon, the harvester displays excellent performance such as relatively high voltage and high power output. We then conducted FEM analysis to validate the hypothetical abrupt flux density changes. A prototype was fabricated for experimental studies. We investigated open-circuit voltage output, current output, and power as well as charging performance into energy storage components. The result shows that harvester possesses excellent performance with the maximum output voltage of 8.64V, peak-peak power of 700mW and the highest volume power density of 24.9mW/cm3. The energy harvester, as a renewable portable power source, can be of great significance for powering smart wearable electronic devices and health care monitoring sensors.

scholarly journals A Magnetically Coupled Electromagnetic Energy Harvester with Low Operating Frequency for Human Body Kinetic Energy

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1300
Author(s):  
Xiang Li ◽  
Jinpeng Meng ◽  
Chongqiu Yang ◽  
Huirong Zhang ◽  
Leian Zhang ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Human Body ◽  
Energy Harvester ◽  
Maximum Output Power ◽  
Excitation Frequency ◽  
Magnetic Coupling ◽  
Interaction Force ◽  
Harmonic Excitation ◽  
Electromagnetic Energy ◽  
Maximum Output

In this paper, a magnetically coupled electromagnetic energy harvester (MCEEH) is proposed for harvesting human body kinetic energy. The proposed MCEEH mainly consists of a pair of spring-connected magnets, coils, and a free-moving magnet. Specifically, the interaction force between the magnets is repulsive. The main feature of this structure is the use of a magnetic-spring structure to weaken the hardening response caused by the repulsive force. The magnetic coupling method enables the energy harvester system to harvest energy efficiently at low frequency. The MCEEH is experimentally investigated for improving energy harvesting efficiency. Under harmonic excitation with an acceleration of 0.5 g, the MCEEH reaches resonance frequency at 8.8 Hz and the maximum output power of the three coils are 5.2 mW, 2.8 mW, and 2.5 mW, respectively. In the case of hand-shaking excitation, the generator can obtain the maximum voltage of 0.6 V under the excitation acceleration of 0.2 g and the excitation frequency of 3.4 Hz. Additionally, a maximum instantaneous power can be obtained of about 26 mW from the human body’s kinetic energy

scholarly journals Double-Deck Metal Solenoids 3D Integrated in Silicon Wafer for Kinetic Energy Harvester

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 74
Author(s):  
Nianying Wang ◽  
Ruofeng Han ◽  
Changnan Chen ◽  
Jiebin Gu ◽  
Xinxin Li
Keyword(s):  
Kinetic Energy ◽  
Power Density ◽  
Energy Harvester ◽  
High Efficiency ◽  
Vibrational Energy ◽  
Average Power ◽  
Wafer Level ◽  
Peak Voltage ◽  
Silicon Mold ◽  
Casting Technique

A silicon-chip based double-deck three-dimensional (3D) solenoidal electromagnetic (EM) kinetic energy harvester is developed to convert low-frequency (<100 Hz) vibrational energy into electricity with high efficiency. With wafer-level micro electro mechanical systems (MEMS) fabrication to form a metal casting mold and the following casting technique to rapidly (within minutes) fill molten ZnAl alloy into the pre-micromachined silicon mold, the 300-turn solenoid coils (150 turns for either inner solenoid or outer solenoid) are fabricated in silicon wafers for saw dicing into chips. A cylindrical permanent magnet is inserted into a pre-etched channel for sliding upon external vibration, which is surrounded by the solenoids. The size of the harvester chip is as small as 10.58 mm × 2.06 mm × 2.55 mm. The internal resistance of the solenoids is about 17.9 Ω. The maximum peak-to-peak voltage and average power output are measured as 120.4 mV and 43.7 μW. The EM energy harvester shows great improvement in power density, which is 786 μW/cm3 and the normalized power density is 98.3 μW/cm3/g. The EM energy harvester is verified by experiment to be able to generate electricity through various human body movements of walking, running and jumping. The wafer-level fabricated chip-style solenoidal EM harvesters are advantageous in uniform performance, small size and volume applications.

scholarly journals Study of the Properties of a Hybrid Piezoelectric and Electromagnetic Energy Harvester for a Civil Engineering Low-Frequency Sloshing Environment

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 391
Author(s):  
Nan Wu ◽  
Yuncheng He ◽  
Jiyang Fu ◽  
Peng Liao
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Civil Engineering ◽  
Maximum Output Power ◽  
Low Frequency ◽  
Electromagnetic Energy ◽  
Maximum Output ◽  
Piezoelectric Film ◽  
Hybrid Energy ◽  
Level Height

In this paper a novel hybrid piezoelectric and electromagnetic energy harvester for civil engineering low-frequency sloshing environment is reported. The architecture, fabrication and characterization of the harvester are discussed. The hybrid energy harvester is composed of a permanent magnet, copper coil, and PVDF(polyvinylidene difluoride) piezoelectric film, and the upper U-tube device containing a cylindrical fluid barrier is connected to the foundation support plate by a hinge and spring. The two primary means of energy collection were through the vortex street, which alternately impacted the PVDF piezoelectric film through fluid shedding, and the electromotive force (EMF) induced by changes in the magnetic field position in the conducting coil. Experimentally, the maximum output power of the piezoelectric transformer of the hybrid energy harvester was 2.47 μW (circuit load 270 kΩ; liquid level height 80 mm); and the maximum output power of the electromagnetic generator was 2.72 μW (circuit load 470 kΩ; liquid level height 60 mm). The low-frequency sloshing energy collected by this energy harvester can drive microsensors for civil engineering monitoring.

scholarly journals Study on the Efficiency and Dynamic Characteristics of an Energy Harvester Based on Flexible Structure Galloping

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6548
Author(s):  
Peng Liao ◽  
Jiyang Fu ◽  
Wenyong Ma ◽  
Yuan Cai ◽  
Yuncheng He
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Physical Model ◽  
Energy Harvester ◽  
High Efficiency ◽  
Lateral Displacement ◽  
Maximum Output Power ◽  
Flexible Structure ◽  
Maximum Output ◽  
Cfd Numerical Simulation

According to the engineering phenomenon of the galloping of ice-coated transmission lines at certain wind speeds, this paper proposes a novel type of energy harvester based on the galloping of a flexible structure. It uses the tension generated by the galloping structure to cause periodic strain on the piezoelectric cantilever beam, which is highly efficient for converting wind energy into electricity. On this basis, a physical model of fluid–structure interaction is established, and the Reynolds-averaged Navier–Stokes equation and SST K -ω turbulent model based on ANSYS Fluent are used to carry out a two-dimensional steady computational fluid dynamics (CFD) numerical simulation. First, the CFD technology under different grid densities and time steps is verified. CFD numerical simulation technology is used to simulate the physical model of the energy harvester, and the effect of wind speed on the lateral displacement and aerodynamic force of the flexible structure is analyzed. In addition, this paper also carries out a parameterized study on the influence of the harvester’s behavior, through the wind tunnel test, focusing on the voltage and electric power output efficiency. The harvester has a maximum output power of 119.7 μW/mm3 at the optimal resistance value of 200 KΩ at a wind speed of 10 m/s. The research results provide certain guidance for the design of a high-efficiency harvester with a square aerodynamic shape and a flexible bluff body.

scholarly journals Topology Selection and Parametric Design of Electromagnetic Vibration Energy Harvesters by Combining FEA-in-the-Loop and Analytical Approaches

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 627 ◽  
Author(s):  
Seong-yeol Yoo ◽  
Young-Woo Park ◽  
Myounggyu Noh
Keyword(s):  
Output Power ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Maximum Output Power ◽  
Electromagnetic Energy ◽  
Vibration Energy ◽  
Maximum Output ◽  
Primary Concern ◽  
Energy Harvesters ◽  
Analytical Approaches

Electromagnetic energy harvesters have been used to capture low-frequency vibration energy of large machines such as diesel generators. The structure of an electromagnetic energy harvester is either planar or tubular. Past research efforts focus on optimally designing each structure separately. An objective comparison between the two structures is necessary in order to decide which structure is advantageous. When comparing the structures, the design variations such as magnetization patterns and the use of yokes must also be considered. In this study, extensive comparisons are made covering all possible topologies of an electromagnetic energy harvester. A bench mark harvester is defined and the parameters that produce maximum output power are identified for each topology. It is found that the tubular harvesters generally produce larger output power than the planar counterparts. The largest output power is generated by the tubular harvester with a Halbach magnetization pattern (94.7 mW). The second best is the tubular harvester with axial magnetization pattern (79.1 mW) when moving yokes are inserted between permanent magnets for flux concentration. When cost is of primary concern, the tubular harvester with axial pattern may become a best option.

An Improved Design Method of High Efficiency Contactless Power Transmission in Ultrasonic Vibration System

2016 ◽  
Vol 693 ◽  
pp. 17-24
Author(s):  
H. Shen ◽  
Ping Fa Feng ◽  
J.F. Zhang ◽  
D.W. Yu ◽  
Z.J. Wu
Keyword(s):  
Flux Density ◽  
Ultrasonic Vibration ◽  
High Efficiency ◽  
Power Transmission ◽  
Design Method ◽  
Experimental Studies ◽  
Mutual Inductance ◽  
Vibration System ◽  
Operation Stability ◽  
Improved Design

To improve the efficiency of contactless power transmission (CPT) and the operation stability of ultrasonic vibration system, an improved design method for key parts of the contactless power transmission system was proposed and studied. By integrating both inductor model and mutual inductance model, as well as considering the fringing flux effect introduced by the air gap, this design method would be more accurate and reasonable. Considering constraint conditions, such as the operating flux density of the core, mutual inductance between primary and secondary coils, electrical signals loaded on ultrasonic vibrator, the coils and cores were designed. Simulation and experimental studies which were developed on flux density, mutual inductance and amplitude output ability of the system, verified that the key parts of CPT system could stay stable during operation and the CPT system was able to transfer ultrasonic energy efficiently.

scholarly journals Experimental studies on the effect of shunted electrical loads on the performance of a vibration-based electromagnetic energy harvester

2021 ◽  
Vol 49 (1) ◽  
pp. 163-172
Author(s):  
Vijay Patil ◽  
Mahadev Sakri
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Internal Resistance ◽  
Open Circuit ◽  
Electromagnetic Energy ◽  
Resistive Load ◽  
Electrical Load ◽  
Load Impedance

At present, the researchers are grappling with the problems of maximizing the output power from a vibration-based electromagnetic energy harvester (VBEH). The parameters affecting the VBEH output power are: electrical damping ratio (ze), mechanical damping ratio (zm) and load impedances of shunted electrical load. Therefore, in this work, the experimental studies are carried out to study the effect of shunted electrical load on: i) the power output of VBEH and, ii) the determination of ze which maximizes the output power. For this purpose, a VBEH is designed and developed to obtain high open-circuit voltage. The effect of resistive, inductive, and capacitive loads on output power of VBEH is investigated using experimental setup developed exclusively for the same. The experimental results reveal that the output power of VBEH is maximum: i) at the resonant frequency ii) when equivalent resistive load impedance equals the internal resistance of electromagnetic coil and iii) value of ze is very small when compared to zm.

An Experimental Study of Low-Frequency Vibration-Based Electromagnetic Energy Harvesters Used while Walking

2014 ◽  
Vol 918 ◽  
pp. 106-114 ◽  
Author(s):  
Min Chie Chiu ◽  
Ying Chun Chang ◽  
Long Jyi Yeh ◽  
Chiu Hung Chung ◽  
Chen Hsin Chu
Keyword(s):  
Kinetic Energy ◽  
Energy Harvester ◽  
Electrical Power ◽  
Research Work ◽  
Low Frequency ◽  
Electrical Energy ◽  
Electromagnetic Energy ◽  
Electromagnetic System ◽  
Energy Harvesters ◽  
Low Frequency Vibration

The goal of this paper is to develop and experimentally test portable vibration-based electromagnetic energy harvesters which are fit for extracting low frequency kinetic energy. Based on a previous study on fixed vibration-based electromagnetic energy harvesters, three kinds of portable energy harvesters (prototype I, prototype II, and prototype III) are developed and tested. To obtain the related parameters of the energy harvesters, an experimental platform used to measure the vibrational systems electrical power at the resonant frequency and other fixed frequencies is also established. Based on the research work of vibration theory, a low frequency vibration-arm mechanism (prototype III) which is easily in resonance with a walking tempo is developed. Here, a strong magnet fixed to one side of the vibration-arm along with a set of wires placed along the vibrating path will generate electricity. The circular device has a radius of 180 mm, a width of 50 mm, and weighs 200 grams. Because of its light mass, it is easy to carry and put into a backpack. Experimental results reveal that the energy harvester (prototype III) can easily transform kinetic energy into electrical power via the vibration-based electromagnetic system when walking at a normal speed. Consequently, electrical energy reaching 0.25 W is generated from the energy harvester (prototype III) by extracting kinetic energy produced by walking.

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