Design and Fabrication of Acoustic Wave Actuated Microgenerator for Portable Electronic Devices

The past few years have seen an increasing focus on energy harvesting issue, including power supply for portable electric devices. Utilize scavenging ambient energy from the environment could eliminate the need for batteries and increase portable device lifetimes indefinitely. In addition, through MEMS technology fabricated micro-generator could easy integrate with these small or portable devices. Several different ambient sources, including solar, vibration and temperature effect, have already exploited [1-3]. Each energy source should be used in suitable environment, therefore to produce maximum efficiency. In this paper, we present an acoustic wave actuated micro-generator for power system by using the energy of acoustic waves, such as the sound from human voices or speakerphone, to actuate a MEMS-type electromagnetic transducer. This provides a longer device lifetime and greater power system convenience. Moreover, it is convenient to integrate MEMS-based microgenerators with small or porta le devicesComment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

DESIGN AND FABRICATION OF ACOUSTIC WAVE ACTUATED MICRO-GENERATOR

The past few years have seen an increasing focus on energy harvesting issue, including power supply for portable electric devices. Utilize scavenging ambient energy from the environment could eliminate the need for batteries and increase portable device lifetimes indefinitely. In addition, through MEMS technology fabricated micro-generator could easy integrate with these small or portable devices. Several different ambient sources, including solar, vibration and temperature effect, have already exploited [1-3]. Each energy source should be used in suitable environment, therefore to produce maximum efficiency. In this paper, we present an acoustic wave actuated micro-generator for power system by using the energy of acoustic waves, such as the sound from human voices or speakerphone, to actuate a MEMS-type electromagnetic transducer. This provides a longer device lifetime and greater power system convenience. Moreover, it is convenient to integrate MEMS-based microgenerators with small or porta le device

A Comparative Study of Electromagnetic Generator via Finite Element Element Analysis

Energy scavenging from ambient sources is an attractive alternative to batteries because of an almost unlimited lifetime and is environmentally safe

Investigating the Optimum Efficiency of Acoustoelectric Conversion Plate Devices

This study aims to develop the acoustoelectric conversion plate in terms of electromagnetic induction law to convert sound energy to electricity, where the developed apparatus is made of three parts, the thin film coil, the spring, and the high-intensity magnetic framework. In process, the thin film coil receives the injecting sound vibration in connection with the spring to cause the reciprocating motion between the coil and the high-intensity magnet, which yields the electromotive force (EMF). In this study, a pearl plate of length 95 mm, width 95 mm, and thickness 1.5 mm adhered with a PET film of thickness 0.08mm is built as the substrate plate due to it has good properties of light and elasticity. In connection with the substrate plate and the electric coil is the thin film coil. Experiments used the speaker with output frequencies of 30~156 Hz and sound power of 0.5 W (sound intensity 0.32 W/m2 , sound pressure level 115 dB) as the sound source. The sound energy is captured by the acoustoelectric conversion plate for working efficiency and optimization parameters analysis. The studied parameters content of diameter, turns, and width of electric coil as well as distance between high intensity magnet and coil. The results show that diameter 0.11 mm, turns 220, and width 3 mm of the electric coil, in connection with steel spring of diameter 0.2 mm while input sound is 30 Hz, receives the average output voltage of 0.57 V, the average output current of 5.46 mA, the average output power of 3.13 mW, and the sound electric conversion efficiency of 0.63%. This innovation device could be used in highway, near waterfalls, and some high noise factories to capture energy for immediately charging cell-phone to save human life

SUSTAINABLE ENERGY HARVESTING TECHNOLOGIES – PAST, PRESENT AND FUTURE

Chapter 8: Energy Harvesting Technologies: Thick-Film Piezoelectric Microgenerato

Piezoelectric Fibers for Sensing and Energy Generation

Au cours de la dernière décennie, la recherche et le développement de générateurs fibrés a reçu une attention significative en raison de la popularité grandissante des appareils électroniques que l’on peut porter, tels que les écrans sur vêtements, les dispositifs de réalité virtuelle, les senseurs médicaux/cliniques portables et les montres intelligentes. Parmi les générateurs fibrés, les fibres piézoélectriques qui opèrent en se basant sur l’effet piézoélectrique sont spécialement attrayantes, parce qu’elles peuvent convertir les vibrations mécaniques de la vie quotidienne (causées par exemple par la marche, les courants d’air ou les battements cardiaques) en signaux électriques. Pour augmenter le potentiel des technologies portables, des textiles piézoélectriques pour alimenter les dispositifs électroniques ont été fabriqués en intégrant les fibres piézoélectriques dans des fibres commerciales utilisant les techniques de fabrication conventionnelles. Les fibres piézoélectriques peuvent aussi avoir des applications techniques dans les domaines de l’information et des communications, dans l’automatisation industrielle, dans le diagnostic médical, dans le control du trafic et dans le secteur de la défense. Par exemple, ces fibres pourraient être implantées dans les avions et les véhicules pour surveiller l’intégrité de la structure mécanique, ainsi qu’alimenter les systèmes électroniques embarqués tels que les réseaux de senseurs sans-fil (WSN) à faible puissance. D’autres applications incluent les détecteurs acoustiques de haute-sensibilité pour la détection des ondes sonores, les actuateurs de micro-positionnement pour les microscopes à force atomique (AFM), les microscopes à effet tunnel (STM), les miroirs laser d’alignement et les dispositifs médicaux implantables (IMD). Encouragés par le marché sans cesse grandissant des appareils électroniques portatifs, des efforts substantiels ont été investis dans la fabrication de fibres piézoélectriques. Aujourd’hui, la plupart des fibres piézoélectriques existantes sont fabriquées soit en faisant croître des nanostructures piézoélectriques dans un filament conducteur ou en extrudant des polymères piézoélectriques avec des polymères conducteurs par trempe sur roue (melt-spinning). La performance et les applications de ces fibres piézoélectriques sont limitées par leur géométries simpliste, leur grandes taille, leur faible fiabilité mécanique, leur coût élevé et leur faible réponse piézoélectrique. Cette thèse a pour objectif de démontrer des fibres piézoélectriques micro et nanostructurées pouvant répondre à ces limitations.----------Abstract In the past decade, the R&D (research and development) of fiber generators has received significant attention due to the growing popularity of wearable mobile electronic systems such as on-garment displays, virtual-reality devices, wearable medical/clinic sensors and smart watches. Among all of these fiber generators, piezoelectric fibers that operate based on piezoelectric effect are especially attractive, because they could convert mechanical vibrations accessible in our daily life (i.e. walking, air flow and heart beating) into electrical signals. To make further improvements to the wearable applications, piezoelectric textiles that power on-body electronics have been fabricated by integrating piezoelectric fibers into commercial fabrics using traditional textile fabrication techniques. Piezoelectric fibers can also find technical applications in the fields of information and communication, industrial automation, medical diagnostics, automation and traffic control, and in the defense industries. For instance, piezoelectric fibers could be implanted on the airplanes and vehicles, for the purpose of structural integrity monitoring, as well as powering the on-board electronic systems such as wireless sensor networks (WSNs) with low-power consumption. Other common examples include ultrasensitive sound detectors for stand-off sound detection, micro-positioning actuators for atomic force microscopes (AFM), scanning tunneling microscopes (STM), and laser mirror alignment; as well as power sources for implanted medical devices (IMDs). Driven by the ever-growing market, extensive effort has been put into the fabrication of piezoelectric fibers. Currently, most of the existing piezoelectric fibers are fabricated either by growing piezoelectric nanostructures along a conductive filament or by extruding piezoelectric polymers together with a conductive polymer by melt-spinning. The performance and applications of these piezoelectric fibers are limited by their simple fiber geometries, large fiber size, poor mechanical reliability, high-cost, and low piezoelectric response. This thesis aims to demonstrate micro- and nanostructured piezoelectric fibers that address these limitations. In our approach, kilometer-long piezoelectric fibers of sub-millimeter diameters are thermally drawn from a macroscopic preform. The piezoelectric fibers feature a soft hollow polycarbonate core surrounded with a spiral multilayer cladding consisting of alternating layers of piezoelectric electrospun nanocomposites (polyvinylidene enhanced with BTO, PZT or CNT)and conductive polymer (carbon filled polyethylene)

Footfall energy harvesting : footfall energy harvesting conversion mechanisms

Ubiquitous computing and pervasive networks are prevailing to impact almost every part of our daily lives. Convergence of technologies has allowed electronic devices to become untethered. Cutting of the power-cord and communications link has provided many benefits, mobility and convenience being the most advantageous, however, an important but lagging technology in this vision is the power source. The trend in power density of batteries has not tracked the advancements in electronic systems development. This has provided opportunity for a bridging technology which uses a more integrated approach with the power source to emerge, where a device has an onboard self sustaining energy supply. This approach promises to close the gap between the increased miniaturisation of electronics systems and the physically constrained battery technology by tapping into the ambient energy available in the surrounding location of an application. Energy harvesting allows some of the costly maintenance and environmentally damaging issues of battery powered systems to be reduced.This work considers the characteristics and energy requirements of wireless sensor and actuator networks. It outlines a range of sources from which the energy can be extracted and then considers the conversion methods which could be employed in such schemes. This research looks at the methods and techniques for harvesting/scavenging energy from ambient sources, in particular from the motion of human traffic on raised flooring and stairwells for the purpose of powering wireless sensor and actuator networks. Mechanisms for the conversion of mechanical energy to electrical energy are evaluated for their benefits in footfall harvesting, from which, two conversion mechanisms are chosen for prototyping.The thesis presents two stair-mounted generator designs. Conversion that extends the intermittent pulses of energy in footfall is shown to be the beneficial. A flyback generator is designed which converts the linear motion of footfall to rotational torque is presented. Secondly, a cantilever design which converts the linear motion to vibration is shown. Both designs are mathematically modelled and the behaviour validated with experimental results & analysis. Power, energy and efficiency characteristics for both mechanisms are compared. Cost of manufacture and reliability are also discussed

Advanced Energy Harvesting Technologies

Energy harvesting is the conversion of unused or wasted energy in the ambient environment into useful electrical energy. It can be used to power small electronic systems such as wireless sensors and is beginning to enable the widespread and maintenance-free deployment of Internet of Things (IoT) technology. This Special Issue is a collection of the latest developments in both fundamental research and system-level integration. This Special Issue features two review papers, covering two of the hottest research topics in the area of energy harvesting: 3D-printed energy harvesting and triboelectric nanogenerators (TENGs). These papers provide a comprehensive survey of their respective research area, highlight the advantages of the technologies and point out challenges in future development. They are must-read papers for those who are active in these areas. This Special Issue also includes ten research papers covering a wide range of energy-harvesting techniques, including electromagnetic and piezoelectric wideband vibration, wind, current-carrying conductors, thermoelectric and solar energy harvesting, etc. Not only are the foundations of these novel energy-harvesting techniques investigated, but the numerical models, power-conditioning circuitry and real-world applications of these novel energy harvesting techniques are also presented

Piezoelectric energy harvesting from low frequency and random excitation using frequency up-conversion

The field of energy harvesting comprises all methods to produce energy locally and from surrounding sources, e.g. solar illumination, thermal gradients, vibration, radio frequency, etc. The focus of this thesis is on inertial power generation from host motion, in particular for low frequency and random excitation sources such as the human body. Under such excitation, the kinetic energy available to be converted into electrical energy is small and conversion efficiency is of utmost importance. Broadband harvesting based on frequency tuning or on non-linear vibrations is a possible strategy to overcome this challenge. The technique of frequency up-conversion, where the low frequency excitation is converted to a higher frequency that is optimal for the operation of the transducer is especially promising. Regardless of the source excitation, energy is converted more efficiently. After a general introduction to the research area, two different prototypes based on this latter principle and using piezoelectric bending beams as transducers are presented, one linear design and one rotational. Especially for human motion, the advantages of rotational designs are discussed. Furthermore, magnetic coupling is used to prevent impact on the brittle piezoceramic material when actuating. A mathematical model, combining the magnetic interaction forces and the constitutive mechanical and electrical equations for the piezoelectric bending beam is introduced and the results are provided. Theoretical findings are supported by experimental measurements and the calculation model is validated. The outcome is the successful demonstration of a rotational energy harvester, tested on a custom made shaking set-up and in the real world when worn on the upper arm during running.Open Acces