241 research outputs found

    Design criteria of a transcutaneous power delivery system for implantable devices.

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    Implantable cardiac assist devices such as artificial hearts and blood pumps are a rapidly growing therapy used for treating moderate to severe congestive heart failure. While current treatments offer improved heart failure survival and increased patient functionality with enhanced quality of life, powering these devices are still constraining. In practice, percutaneous cables passing through skin are used for power and control data transmission requiring patients to maintain a sterile dressing on the skin cable-exit site. This contact site limits patient movement as it is vulnerable to wound infection due to trauma and poor healing. As a result, a sterile dressing has to be maintained and nursed regularly for treating the wound. Complications from the exit site infections are a leading cause of death in long-term support with these devices. Wireless power and control transmission systems have been studied and developed over years in order to avoid percutaneous cables while supplying power efficiently to the implanted device. These power systems, commonly named Transcutaneous Energy Transfer (TET) systems, enable power transmission across the skin without direct electrical connectivity to the power source. TET systems use time-varying electromagnetic induction produced by a primary coil that is usually placed near skin outside the body. The induced voltage in an implanted secondary coil is then rectified and regulated to transfer energy to an implanted rechargeable battery in order to power the biomedical load device. Efficient and optimum energy transfer using such transcutaneous methods is more complex for mobile patients due to coupling discrepancies caused by variations in the alignment of the coil. The research studies equivalent maximum power transfer topologies for evaluating voltage gain and coupling link efficiency of TET system. Also, this research adds to previous efforts by generalizing different scenarios of misalignments of different coil size that affects the coupling link. As a whole, this study of geometric coil misalignments reconsiders potential anatomic location for coil placement to optimize TET systems performance in anticipated environment for efficient and safe operation.--Abstract

    An approach to potential evaluation of a contactless energy supply infrastructure for occasional recharging in production related, non-automated material handling

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    Significant advances have been made in the research and development of electric vehicles (EV’s). Along with the major challenge of energy storage, being also addressed is the efficient design of system energy transfer and consumption. This has had the effect of fundamentally changing perspectives across the mobility and transportation sector. Applied predominantly to road-going vehicles, the industrial context of non-road Electric Vehicles (nrEV’s) and specifically the use of manned electric forklift trucks integrated within the production related materials handling system has, to-date, received far less attention. The overarching aim of this research is to examine the impact and potential for the use of contactless occasional recharging of nrEV’s integrated within a manufacturing line, recognising the need to balance the (sometimes competing) demands of delivering sustainable production while exercising environmental responsibility. Meeting the objectives of this research resulted in the development of a location allocation model for electric charging station determination based on a fundamental understanding of the nature and quality of process inherent key performance indicators (KPI’s) as well as comprehensive process and energy monitoring while considering both Lean and Green Management perspectives. The integration of the generated knowledge and information into a generally valid simulation tool for occasional charging system implementation allows to more thoroughly investigate the impact from occasional charging to overall efficiency and sustainability to be realised. An investigation into relevant literature identified the need for specifically generated energy consumption data and confirmed the need for an energy optimisation model specific to the area of production related materials handling. Empirical data collected from repeated standardised materials handling operations within a selected production related materials handling environment resulted in the development of the Standard Energy Consumption Activity tool (SECA). Further work within this pilot study confirmed the tool as capable of generating reliable and valid data and confirmed the SECA tool as a generally applicable benchmark for energy consumption determination in material handling based on fractional process functions. Integrating this approach into a comprehensive process analysis and charging infrastructure optimisation resulted in the development of an Excel-based simulation model. The (Occasional Charging Station Location Model) OCSLM is based upon Maximal Covering Location Modelling and an endogenous covering distance definition in order to simulate process related potentials and optimal charging system implementation allocations, the target being to increase vehicles usable battery energy. A comprehensive case study based upon six individual and one combined data set confirmed the general and wider applicability of the OCSLM model while the application of the model provides a set of novel results. The application demonstrated a theoretical increase in usable battery energy of between 40% and 60% and within the same case study the impact of technology implementation identified that a reduction in battery and system cost of between 5% and 45% can be realised. However, the use of contactless power transfer resulted in an increase in CO2 emissions of up to 6.89% revealing a negative impact to overall ecology from the use of this energy transfer system. Depending on the availability of fast connecting, contact based energy transmission systems, the approach and results of OCSLM have shown to be directly applicable to contact based systems with resulting CO2 emissions decreasing by 0.94% at an energy transfer efficiency of 96%. Further novelty, of benefit to both academic and industry practice, was realised through the framework and information of the research with the provision of SECA as a process function-based and generally applicable energy consumption standard, OCSLM as a Maximal Covering Location Modell with a focus on occasional charging based on an endogenous covering distance and integrating detailed energy and process monitoring into electric charging station allocation, and the methodology for the application of this approach for fast connecting contactless and contact charging models and cases

    Battery-less near field communications (nfc) sensors for internet of things (iot) applications

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    L’ implementació de la tecnologia de comunicació de camp proper (NFC) en els telèfons intel·ligents no para de créixer degut a l’ús d’aquesta per fer pagaments, això, junt amb el fet de poder aprofitar l’energia generada pel mòbil no només per la comunicació, sinó també per transmetre energia, el baix cost dels xips NFC, i el fet de que els telèfons tinguin connectivitat amb internet, possibilita i fa molt interesant el disseny d’etiquetes sense bateria incorporant-hi sensors i poder enviar la informació al núvol, dins del creixent escenari de l’internet de les coses (IoT). La present Tesi estudia la viabilitat d’aquests sensors, analitzant la màxima distància entre lector i sensor per proveir la potència necessària, presenta tècniques per augmentar el rang d’operació, i analitza els efectes de certs materials quan aquests estan propers a les antenes. Diversos sensors han estat dissenyats i analitzats i son presentats en aquest treball. Aquests son: Una etiqueta que mesura la humitat de la terra, la temperatura i la humitat relativa de l’aire per controlar les condicions de plantes. Un sensor per detectar la humitat en bolquers, imprès en material flexible que s’adapta a la forma del bolquer. Dues aplicacions, una per estimació de pH i una altre per avaluar el grau de maduració de fruites, basats en un sensor de color. I, per últim, s’estudia la viabilitat de sensors en implants per aplicacions mèdiques, analitzant l’efecte del cos i proposant un sistema per augmentar la profunditat a la que aquests es poden llegir utilitzant un telèfon mòbil. Tots aquests sensors poden ser alimentats i llegits per qualsevol dispositiu que disposin de connexió NFC.La implementación de la tecnología de comunicaciones de campo cercano (NFC) en los teléfonos inteligentes no para de crecer debido al uso de esta para llevar a cabo pagos, esto, junto con el hecho de poder aprovechar la energía generada por el móvil no sólo para la comunicación, sino también para transmitir energía, el bajo coste de los chips NFC, i el hecho que los teléfonos tengan conectividad a internet, posibilita y hace muy interesante el diseño de etiquetas sin batería que incorporen sensores i poder enviar la información a la nube, enmarcado en el creciente escenario del internet de las cosas (IoT). La presente Tesis estudia la viabilidad de estos sensores, analizando la máxima distancia entre lector i sensor para proveer la potencia necesaria, presenta técnicas para aumentar el rango de operación, y analiza los efectos de ciertos materiales cuando estos están cerca de las antenas. Varios sensores han sido diseñados y analizados y son presentados en este trabajo. Estos son: Una etiqueta que mide la humedad de la tierra, la temperatura y la humedad relativa del aire para controlar las condiciones de plantas. Un sensor para detectar la humedad en pañales, impreso en material flexible que se adapta a la forma del pañal. Dos aplicaciones, una para estimación de pH y otra para evaluar el grado de maduración de frutas, basados en un sensor de color. Y, por último, se estudia la viabilidad de sensores en implantes para aplicaciones médicas, analizando el efecto del cuerpo y proponiendo un sistema para aumentar la profundidad a la que estos se pueden leer usando un teléfono móvil. Todos estos sensores pueden ser alimentados y leídos por cualquier dispositivo que disponga de conexión NFC.The implementation of near field communication (NFC) technology into smartphones grows rapidly due the use of this technology as a payment system. This, altogether with the fact that the energy generated by the phone can be used not only to communicate but for power transfer as well, the low-cost of the NFC chips, and the fact that the smartphones have connectivity to internet, makes possible and very interesting the design of battery-less sensing tags which information can be sent to the cloud, within the growing internet of things (IoT) scenario. This Thesis studies the feasibility of these sensors, analysing the maximum distance between reader and sensor to provide the necessary power, presents techniques to increase the range of operation, and analyses the effects of certain materials when they are near to the antennas. Several sensors have been designed and analysed and are presented in this work. These are: a tag that measures the soil moisture, the temperature and the relative humidity of the air to control the conditions of plants. A moisture sensor for diapers, printed on flexible material that adapts to the diaper shape. Two applications, one for pH estimation and another for assessing the degree of fruit ripening, based on a colour sensor. And finally, the feasibility of sensors in implants for medical applications is studied, analysing the effect of the body and proposing a system to increase the depth at which they can be read using a mobile phone. All of these sensors can be powered and read by any NFC enabled device

    Automatic Positioning System for Inductive Wireless Charging Devices and Application to Mobile Robot

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    Inductive power transfer (IPT) remains one of the most common ways to achieve wireless power transfer (WPT), operating on the same electromagnetic principle as electrical transformers but with an air core. IPT has recently been implemented in wireless charging of consumer products such as smartphones and electric vehicles. However, one major challenge with using IPT remains ensuring precise alignment between the transmitting and receiving coils so that maximum power transfer can take place. In literature, much of the focus is on improving the electrical circuits or IPT coil geometries to allow a greater transmission range. Nevertheless, most IPT products today rely on precise alignment for efficient power transfer. In this thesis, the use of sensing coils to detect and correct lateral misalignments in a typical IPT system is modeled and tested. The sensing coils exploit magnetic-field symmetry to give a nonlinear measure of misalignment direction and magnitude. To test this idea, three experiments are performed: 1) measure the voltage of experimental sensing coils for various lateral misalignment distances, 2) implement closed-loop control and measure performance for an experimental two-dimensional (2D) automatic IPT alignment mechanism, and 3) test automatic IPT alignment on a plausible mobile robot wireless charging scenario. The experimental sensing coils give a misalignment sensing resolution of 1 mm or less in two lateral directions, allowing automatic alignment control in real time with a maximum lateral positioning error of less than √2 mm. This precise alignment allows for efficient power transfer to occur. When implemented on the mobile robot platform, the automatic positioning system gives similar results, allowing the robot to position itself above a wireless charger precisely—a task the mobile robot cannot accomplish using its navigation camera alone. The results of this experiment give confidence that similar sensing coils can be used to reduce lateral misalignments in scaled IPT systems, such as electric-vehicle wireless chargers

    Acoustic power distribution techniques for wireless sensor networks

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    Recent advancements in wireless power transfer technologies can solve several residual problems concerning the maintenance of wireless sensor networks. Among these, air-based acoustic systems are still less exploited, with considerable potential for powering sensor nodes. This thesis aims to understand the significant parameters for acoustic power transfer in air, comprehend the losses, and quantify the limitations in terms of distance, alignment, frequency, and power transfer efficiency. This research outlines the basic concepts and equations overlooking sound wave propagation, system losses, and safety regulations to understand the prospects and limitations of acoustic power transfer. First, a theoretical model was established to define the diffraction and attenuation losses in the system. Different off-the-shelf transducers were experimentally investigated, showing that the FUS-40E transducer is most appropriate for this work. Subsequently, different load-matching techniques are analysed to identify the optimum method to deliver power. The analytical results were experimentally validated, and complex impedance matching increased the bandwidth from 1.5 to 4 and the power transfer efficiency from 0.02% to 0.43%. Subsequently, a detailed 3D profiling of the acoustic system in the far-field region was provided, analysing the receiver sensitivity to disturbances in separation distance, receiver orientation and alignment. The measured effects of misalignment between the transducers are provided as a design graph, correlating the output power as a function of separation distance, offset, loading methods and operating frequency. Finally, a two-stage wireless power network is designed, where energy packets are inductively delivered to a cluster of nodes by a recharge vehicle and later acoustically distributed to devices within the cluster. A novel dynamic recharge scheduling algorithm that combines weighted genetic clustering with nearest neighbour search is developed to jointly minimise vehicle travel distance and power transfer losses. The efficacy and performance of the algorithm are evaluated in simulation using experimentally derived traces that presented 90% throughput for large, dense networks.Open Acces

    ESSE 2017. Proceedings of the International Conference on Environmental Science and Sustainable Energy

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    Environmental science is an interdisciplinary academic field that integrates physical-, biological-, and information sciences to study and solve environmental problems. ESSE - The International Conference on Environmental Science and Sustainable Energy provides a platform for experts, professionals, and researchers to share updated information and stimulate the communication with each other. In 2017 it was held in Suzhou, China June 23-25, 2017

    Insights from the Inventory of Smart Grid Projects in Europe: 2012 Update

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    By the end of 2010 the Joint Research Centre, the European Commission’s in-house science service, launched the first comprehensive inventory of smart grid projects in Europe1. The final catalogue was published in July 2011 and included 219 smart grid and smart metering projects from the EU-28 member states, Switzerland and Norway. The participation of the project coordinators and the reception of the report by the smart grid community were extremely positive. Due to its success, the European Commission decided that the project inventory would be carried out on a regular basis so as to constantly update the picture of smart grid developments in Europe and keep track of lessons learnt and of challenges and opportunities. For this, a new on-line questionnaire was launched in March 2012 and information on projects collected up to September 2012. At the same time an extensive search of project information on the internet and through cooperation links with other European research organizations was conducted. The resulting final database is the most up to date and comprehensive inventory of smart grids and smart metering projects in Europe, including a total of 281 smart grid projects and 90 smart metering pilot projects and rollouts from the same 30 countries that were included in the 2011 inventory database. Projects surveyed were classified into three categories: R&D, demonstration or pre-deployment) and deployment, and for the first time a distinction between smart grid and smart metering projects was made. The following is an insight into the 2012 report.JRC.F.3-Energy securit

    Inductive wireless power transmission for automotive applications

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    Technology has revolutionised all aspects of human life at all consecutive intervals and Fourth Industrial Revolution is no different. Daily transport and energy industries not only shape the future of a country’s economy, but also make the economy highly yielding due to recent advances. Electric vehicles (EV) have been rapidly invading the market share during recent years. The advancements in EV and enhanced market share demand EV charging, being more reliant on either conventional plug-in charging or wireless charging. Given the limitations within battery related apparatus such as escalating battery costs, higher weight and lower power density, wireless power transfer (WPT) is a novel state of the art technology in energising. WPT has remarkable characteristics such as enhanced flexibility, mobility, convenience and safety, indicating potential benefits, if it is adopted for EV with similar efficiency; for example, it can eliminate the use of charging cables. Despite the fact that the wireless charges for EV, have undergone significant development phase during the last decade, many design limitations are yet to be addressed. Although the technology has been commercially outgrown, key limitations such as limited efficiency over distance, limited driving range, vulnerability to misalignments, or positional offsets are yet to be researched. Moreover, although high system efficiency can be attained, the distance variations between the transmitter and receiver and the misalignments will impact the system efficiency. This thesis addresses the aforementioned limitations and design challenges of the magnetic resonance WPT system, and proposes a novel transmitter and receiver circuit and coil designs, to minimise the impact of distance variations and coil misplacement, reduce the size and improve charging performance. This thesis focusses on inductive wireless power transfer (IWPT) which is also referred to as magnetic resonance and reviews and contrasts other WPT mechanisms. Additionally, it presents a detailed mathematical analysis of inductive wireless power circuit model to obtain accurate modelling parameters. Two and four loop strongly coupled magnetic resonance (SCMR) wireless power systems have been mathematically analysed and their performance has been evaluated. A novel combined, conformal strongly coupled magnetic resonance system (CSCMR) has been combined with SCMR, in order to minimise the dimensions of the receiver and compensate the coupling factor due to distance variations between the transmitter and receiver. In the second phase, additional inductors were added to the existing loosely coupled system to obtain higher efficiencies over higher distances. The size of the system has significantly reduced due to the additional smaller transmitter and receiver inductor which were added to the existing system to achieve better performance. The validity of each design has been discussed via a set of simulations, and their measurements have been obtained via prototypes. Finally, a smart WPT charging system, consisting of six transmitter loops and a sensor network array, for an autonomous parking space was developed. The proposed method reduces the energy required for determining a car’s location, eventually increasing the performance of the charger
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