scholarly journals Shaft Integrated Electromagnetic Energy Harvester with Gravitational Torque

Designs ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 16
Author(s):  
Michel Ullrich ◽  
Maik Wolf ◽  
Mathias Rudolph ◽  
Wolfgang Diller
Keyword(s):  
Energy Supply ◽  
Energy Harvester ◽  
Early Stage ◽  
Electrical Power ◽  
Rolling Bearing ◽  
Electromagnetic Energy ◽  
Simulation Studies ◽  
Rotating Shafts ◽  
Electrical Power Output ◽  
Electrical Supply

This paper presents the development of an electromagnetic energy harvester for electrical supply of a sensor unit integrated on the rotating inner ring of a rolling bearing. This energy harvester is of special interest for condition monitoring tasks on rotating shafts. A sensory monitor on the inner ring can detect wear conditions at an early stage. The harvester works without mechanical and energetic contact to surrounding components by utilizing the rotational energy of the shaft. The functionality of the Energy Harvester is enabled by the inertia principle, which is caused by an asymmetrical mass distribution. We provide simulations to validate the designs. This work includes simulation studies on the electrical power output of the harvester. Therefore, the necessary simulation of the magnetic problems is realized in a substitute simulation environment. The harvester design enables existing machines to be equipped with the harvester to provide an energy supply on rotating shafts. This clamp connection enables shaft mounting independent of location without mechanical work on the shaft. With an electrical power of up to 163.6 m W, at 3600 rpm, the harvester is used as an energy supply, which enables sensor-based monitoring of slow wear processes.

scholarly journals Evaluating Energy Generation Capacity of PVDF Sensors: Effects of Sensor Geometry and Loading

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1895
Author(s):  
Mohammad Uddin ◽  
Shane Alford ◽  
Syed Mahfuzul Aziz
Keyword(s):  
Surface Area ◽  
Power Output ◽  
Energy Harvester ◽  
Mechanical Strain ◽  
Electrical Power ◽  
Human Movement ◽  
Loading Frequency ◽  
Dielectric Thickness ◽  
Generating Capacity ◽  
Electrical Power Output

This paper focuses on the energy generating capacity of polyvinylidene difluoride (PVDF) piezoelectric material through a number of prototype sensors with different geometric and loading characteristics. The effect of sensor configuration, surface area, dielectric thickness, aspect ratio, loading frequency and strain on electrical power output was investigated systematically. Results showed that parallel bimorph sensor was found to be the best energy harvester, with measured capacitance being reasonably acceptable. Power output increased with the increase of sensor’s surface area, loading frequency, and mechanical strain, but decreased with the increase of the sensor thickness. For all scenarios, sensors under flicking loading exhibited higher power output than that under bending. A widely used energy harvesting circuit had been utilized successfully to convert the AC signal to DC, but at the sacrifice of some losses in power output. This study provided a useful insight and experimental validation into the optimization process for an energy harvester based on human movement for future development.

Passive Energy Harvesting From Human Activities

2009 ◽  
Author(s):  
Edwar Romero ◽  
Michael R. Neuman ◽  
Robert O. Warrington
Keyword(s):  
Energy Harvesting ◽  
Human Activities ◽  
Energy Harvester ◽  
Electrical Power ◽  
Electrical Potential ◽  
Human Motion ◽  
Planar Coil ◽  
Solar Powered ◽  
The One ◽  
Electrical Power Output

Energy harvesting from environmental sources such as motion, light, and temperature changes, has been demonstrated with commercially viable products (such as human-powered flashlights, solar-powered calculators, and thermal-powered wristwatches). Vibration or motion is an attractive environmental energy source due to its abundance and availability. A new electromagnetic energy harvester presented here is found to be capable for scavenging energy from human motion. The electrical power output of an inertial energy scavenger is proportional to the acceleration-squared-to-frequency (ASTF) and the quality (Q) factor. Human motion is associated with large ASTF values and low Q factors while machine vibrations are usually related with the opposite. Thus, passive energy harvesting from human activities could generate as much power as the one available from machine harvesters. The limit for such inertial generator is estimated to be on the order of 1mW/cm3. This paper reviews the energy harvesting limits, the energy generation from human activities, and the development of a new oscillating electromagnetic generator. This energy harvester is built with a permanent magnet (PM) ring with multiple poles and a gear-shaped planar coil. The PM ring has attached an eccentric proof mass for converting external movement into oscillations or rotations, these oscillations induce an electrical potential on the planar coil. As much as 3.45μW of power have been generated with a prototype at a frequency of 2.7Hz on a laboratory shaker and 2.35μW had been obtained when positioned laterally on the hip while walking.

scholarly journals Numerical Assessment of a One-Mass Spring-Based Electromagnetic Energy Harvester on a Vibrating Object

2016 ◽  
Vol 41 (1) ◽  
pp. 119-131 ◽  
Author(s):  
Min-Chie Chiu ◽  
Ying-Chun Chang ◽  
Long-Jyi Yeh ◽  
Chiu-Hung Chung
Keyword(s):  
Optimal Design ◽  
Energy Harvester ◽  
Damping Ratio ◽  
Electrical Power ◽  
Electromagnetic Energy ◽  
Design Parameters ◽  
Helical Springs ◽  
Spring Wire ◽  
Excitation Period ◽  
Mass Spring

Abstract The paper is an exploration of the optimal design parameters of a space-constrained electromagnetic vibration-based generator. An electromagnetic energy harvester is composed of a coiled polyoxymethylen circular shell, a cylindrical NdFeB magnet, and a pair of helical springs. The magnet is vertically confined between the helical springs that serve as a vibrator. The electrical power connected to the coil is actuated when the energy harvester is vibrated by an external force causing the vibrator to periodically move through the coil. The primary factors of the electrical power generated from the energy harvester include a magnet, a spring, a coil, an excited frequency, an excited amplitude, and a design space. In order to obtain maximal electrical power during the excitation period, it is necessary to set the system’s natural frequency equal to the external forcing frequency. There are ten design factors of the energy harvester including the magnet diameter (Dm), the magnet height (Hm), the system damping ratio (ζsys), the spring diameter (Ds), the diameter of the spring wire (ds), the spring length (ℓs), the pitch of the spring (ps), the spring’s number of revolutions (Ns), the coil diameter (Dc), the diameter of the coil wire (dc), and the coil’s number of revolutions (Nc). Because of the mutual effects of the above factors, searching for the appropriate design parameters within a constrained space is complicated. Concerning their geometric allocation, the above ten design parameters are reduced to four (Dm, Hm, ζsys, and Nc). In order to search for optimal electrical power, the objective function of the electrical power is maximized by adjusting the four design parameters (Dm, Hm, ζsys, and Nc) via the simulated annealing method. Consequently, the optimal design parameters of Dm, Hm, ζsys, and Nc that produce maximum electrical power for an electromagnetic energy harvester are found.

Influence of Nonlinear Effects on a Piezoelectric Energy Harvesting Device

2012 ◽  
Author(s):  
Andreza T. Mineto ◽  
Paulo S. Varoto
Keyword(s):  
Energy Harvester ◽  
Electrical Power ◽  
Nonlinear Effects ◽  
Analytical Investigation ◽  
Frequency Range ◽  
Lumped Mass ◽  
Coupled Equations ◽  
Piezoelectric Energy ◽  
Electrical Power Output ◽  
Tip Mass

In this paper we present an analytical investigation of a nonlinear energy harvester device. The device is composed of a cantilever beam partially covered by piezoelectric ceramics in a bimorph configuration with a magnetic lumped mass attached to the beam’s free end. The model accounts for the nonlinearity coming from the piezoelectric constitutive equations in addition to the nonlinear effect arising from the magnetic field generated by the magnetic properties of the tip mass and additional magnetic sources in the vicinity of the beam. The electromechanical coupled equations are solved numerically through the initial value problems for ordinary differential equations. The electrical power output is calculated by varying the amplitude of the base acceleration, the distance between the magnets and the load resistor. The stability of the system is also investigated. From the numerical results it is found that the influence of the parameters investigated in the frequency range of operation of the device and the nonlinear effects present on the device energy harvester extend the useful frequency range of these.

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.

scholarly journals Physical realisation of a nonlinear electromagnetic energy harvester for rotational applications

2021 ◽  
pp. 095440622098519
Author(s):  
B Gunn ◽  
S Theodossiades ◽  
SJ Rothberg
Keyword(s):  
Energy Harvester ◽  
Experimental Testing ◽  
Electrical Power ◽  
Vibration Energy ◽  
Rotating Shaft ◽  
Vibration Energy Harvester ◽  
Physical Prototype ◽  
Rotational Vibration ◽  
Rotating Shafts ◽  
Speed Fluctuations

Control and structural health monitoring sensors are becoming increasingly common in industrial and household applications due to recent advances reducing their manufacturing costs, size and power consumption. Nevertheless, providing power for these sensors poses a key challenge to engineers, particularly in system locations where limited access renders regular maintenance infeasible due to high associated costs. In the present work, the design and physical prototype testing of a nonlinear electromagnetic vibration energy harvester is presented based on a previously reported concept of the authors. The harvester is activated by the torsional speed fluctuations of a rotating shaft. Experimental testing in a rig driven by an electric motor confirms the harvester’s properties and the modelled oscillatory behaviour. This novel rotational vibration energy harvester concept may generate over 10 mW of electrical power for a broadband speed range of approximately 400 rpm (in the examined rotational system with set fluctuating speed) for wireless sensing purposes on rotating shafts.

Scavenging vibrational energy with a novel bistable electromagnetic energy harvester

2020 ◽  
Vol 29 (2) ◽  
pp. 025022 ◽  
Author(s):  
Bo Yan ◽  
Ning Yu ◽  
Lu Zhang ◽  
Hongye Ma ◽  
Chuanyu Wu ◽  
...  
Keyword(s):  
Energy Harvester ◽  
Vibrational Energy ◽  
Electromagnetic Energy

scholarly journals Near-field thermophotovoltaics for efficient heat to electricity conversion at high power density

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rohith Mittapally ◽  
Byungjun Lee ◽  
Linxiao Zhu ◽  
Amin Reihani ◽  
Ju Won Lim ◽  
...  
Keyword(s):  
Power Density ◽  
High Power ◽  
High Efficiency ◽  
Near Field ◽  
Electrical Power ◽  
Photovoltaic Cells ◽  
High Power Density ◽  
Pv Cell ◽  
Electrical Power Output ◽  
Power Densities

AbstractThermophotovoltaic approaches that take advantage of near-field evanescent modes are being actively explored due to their potential for high-power density and high-efficiency energy conversion. However, progress towards functional near-field thermophotovoltaic devices has been limited by challenges in creating thermally robust planar emitters and photovoltaic cells designed for near-field thermal radiation. Here, we demonstrate record power densities of ~5 kW/m2 at an efficiency of 6.8%, where the efficiency of the system is defined as the ratio of the electrical power output of the PV cell to the radiative heat transfer from the emitter to the PV cell. This was accomplished by developing novel emitter devices that can sustain temperatures as high as 1270 K and positioning them into the near-field (<100 nm) of custom-fabricated InGaAs-based thin film photovoltaic cells. In addition to demonstrating efficient heat-to-electricity conversion at high power density, we report the performance of thermophotovoltaic devices across a range of emitter temperatures (~800 K–1270 K) and gap sizes (70 nm–7 µm). The methods and insights achieved in this work represent a critical step towards understanding the fundamental principles of harvesting thermal energy in the near-field.

scholarly journals Load Resistance Optimization of Bi-Stable Electromagnetic Energy Harvester Based on Harmonic Balance

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1505
Author(s):  
Sungryong Bae ◽  
Pilkee Kim
Keyword(s):  
External Load ◽  
Harmonic Balance ◽  
Energy Harvester ◽  
Load Resistance ◽  
Electromagnetic Energy ◽  
Analytic Approach ◽  
Accurate Estimation ◽  
Vibration Source ◽  
Optimal Load ◽  
Matching Techniques

In this study, a semi-analytic approach to optimizing the external load resistance of a bi-stable electromagnetic energy harvester is presented based on the harmonic balance method. The harmonic balance analyses for the primary harmonic (period-1T) and two subharmonic (period-3T and 5T) interwell motions of the energy harvester are performed with the Fourier series solutions of the individual motions determined by spectral analyses. For each motion, an optimization problem for maximizing the output power of the energy harvester is formulated based on the harmonic balance solutions and then solved to estimate the optimal external load resistance. The results of a parametric study show that the optimal load resistance significantly depends on the inductive reactance and internal resistance of a solenoid coil––the higher the oscillation frequency of an interwell motion (or the larger the inductance of the coil) is, the larger the optimal load resistance. In particular, when the frequency of the ambient vibration source is relatively high, the non-linear dynamic characteristics of an interwell motion should be considered in the optimization process of the electromagnetic energy harvester. Compared with conventional resistance-matching techniques, the proposed semi-analytic approach could provide a more accurate estimation of the external load resistance.

Sign in / Sign up

Export Citation Format

Share Document