System data communication structures for active-control transport aircraft, volume 2

The application of communication structures to advanced transport aircraft are addressed. First, a set of avionic functional requirements is established, and a baseline set of avionics equipment is defined that will meet the requirements. Three alternative configurations for this equipment are then identified that represent the evolution toward more dispersed systems. Candidate communication structures are proposed for each system configuration, and these are compared using trade off analyses; these analyses emphasize reliability but also address complexity. Multiplex buses are recognized as the likely near term choice with mesh networks being desirable for advanced, highly dispersed systems

Studies in Electrical Machines & Wind Turbines associated with developing Reliable Power Generation

The publications listed in date order in this document are offered for the Degree of Doctor of Science in Durham University and have been selected from the author’s full publication list. The papers in this thesis constitute a continuum of original work in fundamental and applied electrical science, spanning 30 years, deployed on real industrial problems, making a significant contribution to conventional and renewable energy power generation. This is the basis of a claim of high distinction, constituting an original and substantial contribution to engineering science

Development of an Integrated Methodology to Estimate Groundwater Vulnerability to Pollution in Karst Areas

Groundwater is a very important resource since water volumes stored underground are much larger compared with those located at the surface, such as rivers and lakes. Aquifers supply a high percentage of freshwater for human consumption as well as supplying economic activities like industry, agriculture, and livestock production. Among them, karst aquifers stand out due to their special hydrologic characteristics and behaviour. In karst aquifers, infiltration occurs faster in comparison with unconsolidated aquifers, due to high permeability features at the surface like dolines, karren, epikarst, and swallow holes that allow precipitating water to recharge the aquifer at higher rates. Nevertheless, these characteristics also increase the aquifer’s susceptibility to being affected by pollution generated by anthropogenic practices. With a low natural pollutant degradation capacity, karst systems mostly experience problems related with water quality rather than water quantity. At present, this represents a significant challenge because a high percentage of the world population is settled on karst areas and is solely dependent upon karst aquifers to fulfil their necessary water supply. A good example to represent this case is the Yucatan Peninsula. The Peninsula is a transboundary limestone platform, covering parts of Mexico, Belize, and Guatemala, whose characteristics do not allow surface streams to generate. Therefore, the karstic aquifer provides water for nearly 4.5 million inhabitants within Mexican territory; this estimation excludes water volumes used for economic activities. The anthropogenic impacts over this karst aquifer have generated problems for water intended for human consumption, furthered by weak environmental regulations that allow the disposal of wastewater without adequate treatment. In the Mexican state of Yucatan, roughly 10% of the population has access to public sewer services where wastewater is treated. Additionally, the use of fertilizers and pesticides is not regulated in agricultural areas, while pig farming is an increasing activity, which fails to keep the necessary standards for the proper disposal of pig slurry. Similar situations can be found around the world, thus the development of plans and strategies to preserve karst groundwater quality that aim to find a balance between resource protection and regional development is increasingly necessary. One important tool emerged to support decisions regarding groundwater protection: the groundwater vulnerability concept. However, due to the hydrologic differences among detritus and karst aquifers, the vulnerability concept, which was first promoted for the former aquifer type, necessitated the development of a specialized vulnerability method to consider the natural characteristics of karst landscapes. Nevertheless, due to the high heterogeneity and anisotropy present in karst systems several methodologies to estimate karst groundwater vulnerability have arisen. Current methodologies are theoretical approximations to differentiate areas where an assumed pollutant particle, released at the surface, is more likely to reach the aquifer due to the natural characteristics of the area. These methods have shown themselves to be useful in defining protection areas and in highlighting regions in which further studies can be performed. However, the high subjectivity and exclusion of anthropogenic influences as part of the analysis is a drawback for these methods. In order to estimate karst groundwater vulnerability for current and future scenarios, an integrated approach is highly necessary. Since most of the methods focus solely on the travel time of a theoretical pollutant from the surface towards groundwater or to a spring, inclusion of pollutants residence time and concentration as parameters to estimate vulnerability is of the uttermost importance. To reach this goal, it is necessary to investigate current intrinsic-based methods in terms of their applicability and regional congruence in order to highlight advantages and probable misclassifications among them and to propose improvements. Pollutant residence time and concentration can be estimated from modelling, which can highlight areas where pollution can represent a problem due to anthropogenic practices, such as wastewater disposal and water extraction fields influencing groundwater flow. Other problems to be contemplated are the data availability and the variable processes by which areas are classified as vulnerable or not. Evaluation of multiple criteria to define degrees of vulnerability is complicated, since several factors, such as subjectivity, data quality, scale, and regional conditions, will always be present. This work presents the results from the application of eight karst groundwater vulnerability methods to the Yucatan karst and outcomes from solute transport. Important considerations are explained in order to improve the workflow for intrinsic groundwater vulnerability assessment. Possible parameters, to be included as part of vulnerability analysis, are evaluated by modelling, demonstrating the importance of anthropogenic impacts for current vulnerability scenarios. Results obtained in this research are displayed as the basis for an Integrated Karst Aquifer Vulnerability (IKAV) method proposed as an alternative for vulnerability studies

Model-based Condition Monitoring of Anti-lock Braking Systems

The Anti-lock Braking System (ABS) is one of the most important safety features in modern vehicles. It is a device integrating complicated electronic systems, hydraulic systems and mechanical components. It is possible to produce faults in these systems due to extreme vehicle operating conditions, which may lead to the failure of the ABS. However, there has not been an effective mechanism available in current operation and service facilities, which allows the performance of the ABS to be checked on-board or at a service base. This research therefore aims to investigate and develop approaches which allow the ABS systems to be monitored in different ways. As the ABS is a highly integrated system, conventional monitoring methods cannot be applied to it directly. The primary objective of this research is to develop a condition monitoring model for a typical ABS system under different conditions and then to monitor the dynamic characteristics and performance of the ABS according to simulation and experimental results. The Rapid Control Prototype (RCP) technique is used by applying dSpace MicroAutoBoxII on the ABS controller. A full mathematical model has been developed to simulate the ABS system under different conditions and seeded fault conditions. This results in a full understanding of the characteristics of measurable variables such as wheel velocity and vehicle velocity. This work has led to the conclusion that a model-based condition monitoring approach is the method with the most potential for the monitoring of the ABS systems. To overcome inevitable measurement noise and model uncertainties, a Kalman filter (KF) has been designed and evaluated through both simulation data and experimental results. This has been found to have acceptable performance and has subsequently been incorporated into the model-based condition monitoring system. The performance of the model-based condition monitoring system has been evaluated using an ABS test system. The ABS test rig consists of the basic ABS components and also the dSpace MicroAutoBoxII components, together with NI data acquisition equipment. The ABS test rig developed in this research is highly flexible to allow experimental investigations under different fault conditions with different severities. It has demonstrated that the monitoring system can reliably detect different possible faults in the ABS such as speed sensor failure, solenoid valve sticking or stuck, hydraulic fluid leakage and pump efficiency loss. All these faults occur with high possibility according to a systematic failure mode analysis based on that of similar components. Obviously, there is still considerable work which needs to be carried out to adopt this system in industry. For example, interfaces to integrate this new system into existing vehicle electronics should be investigated. In addition, specific fault conditions from different vehicle manufacturers should be simulated to tailor the system to specific vehicles specifically

Design optimization and performance analysis methodology for PMSMs to improve efficiency in hydraulic applications

Pla de Doctorats Industrials de la Generalitat de CatalunyaIn the recent years, water pumping and other hydraulic applications are increasingly demanding motors capable to operate under different working conditions, including variable pressure and volumetric flow demands. Moreover, the technical evolution trend of pumping components is to minimize the size, offering compact and adaptable hydraulic units. Hence, the need to optimize the electric motor part to reduce the volume according this trend, maximizing the efficiency, decreasing material and fabrication costs, reducing noise and improving thermal dissipation have originated the research field of this project. So far different methodologies have been focused on designing electrical machines considering few aspects, such as the rated conditions with some size limitations. In addition, the optimization strategies have been based on single operation conditions, improving multiple aspects but not considering the overall performance of the machine and its influence with the working system. This research changes the design and optimization paradigm, focusing on defining beforehand the desired performance of the electrical machine in relation with the application system. The customization is not limited to an operating point but to the whole performance space, which in this case is the torque-speed area. Thus, the designer has plenty of freedom to study the system, and define the desired motor performance establishing the size, thermal and mechanical limitations from the beginning of the process. Moreover, when designing and optimizing electrical machines, the experimental validation is of major importance. From an industrial scope so far, the testing methodologies are focused on evaluating point by point the electrical machine performance, being a robust and trustable way to measure and validate the electrical machine characteristics. Nevertheless,this method requires a large time to prepare the experimental setup and to evaluate the whole motor performance. For this reason, there is a special interest on improving parameter estimation and performance evaluation techniques for electrical machines to reduce evaluation time, setup complexity and increase the number of physical magnitudes to measure in order to have deeper information. This research also develops methodologies to extend the electrical machine experimental validation providing information to evaluate the motor performance. This doctoral thesis has been developed with a collaboration agreement between UPC and the company MIDTAL TALENTOS S.L. The thesis is included within the Industrial Doctorates program 2018 DI 019 promoted by the Generalitat de Catalunya.En los últimos años, el bombeo de agua, entre otras aplicaciones hidráulicas, exige cada vez más motores capaces de operar en diferentes condiciones de trabajo, incluyendo las demandas variables de presión y caudal volumétrico. Además, la evolución técnica de los componentes de bombeo está cada vez más minimizando el tamaño ofreciendo unidades hidráulicas compactas y adaptables. De ahí la necesidad de optimizar la parte del motor eléctrico para reducir el volumen de acuerdo con esta tendencia, maximizando la eficiencia, disminuyendo los costos de material y fabricación, reduciendo el ruido y mejorando la disipación térmica. Todos estos factores han creado el campo de investigación sobre el cual se desarrolla este proyecto. Hasta ahora las metodologías se han centrado en diseñar las máquinas eléctricas considerando unos pocos aspectos técnicos, como las condiciones nominales con algunas limitaciones de tamaño. Además, las estrategias de optimización se han basado en condiciones de operación única, mejorando múltiples aspectos sin considerar el rendimiento general de la máquina y su influencia en el sistema de trabajo. Esta investigación cambia el paradigma de diseño y optimización centrándose en definir de antemano el rendimiento deseado de la máquina eléctrica en relación con el sistema de aplicación. La personalización no se limita a un punto de funcionamiento sino a todo el espacio de operación, que en este caso se expresa en el espacio par-velocidad. Así, el diseñador tiene libertad para estudiar el sistema, definir el rendimiento deseado del motor estableciendo el tamaño, limitaciones térmicas y mecánicas desde el inicio del proceso. Además, a la hora de diseñar y optimizar máquinas eléctricas, la validación experimental es de gran importancia. En el ámbito industrial hasta ahora, las metodologías de ensayo han sido enfocadas a evaluar punto por punto la máquina eléctrica, siendo una forma robusta y confiable de medir y validar sus características. Sin embargo, este método requiere mucho tiempo para preparar la configuración experimental y evaluar el motor en toda su zona de operación. Por esta razón, existe un interés especial en mejorar la estimación de parámetros y las técnicas de evaluación de la operación de las máquinas eléctricas reduciendo tiempo, complejidad y aumentando el número de magnitudes físicas a medir teniendo más información sobre la máquina. Esta investigación también desarrolla metodologías para extender la validación experimental de la máquina eléctrica proporcionando información para evaluar el rendimiento del motor. Esta tesis doctoral ha sido desarrollada con un convenio de colaboración entre la Universidad Politécnica de Cataluña UPC y la empresa MIDTAL TALENTOS S.L. La tesis se engloba dentro del plan de Doctorados Industriales 2018 DI 019 impulsado por la Generalitat de Catalunya.Postprint (published version

High Fidelity Model of Ball Screws to Support Model-based Health Monitoring

L'abstract è presente nell'allegato / the abstract is in the attachmen

Fault tolerant programmable digital attitude control electronics study

The attitude control electronics mechanization study to develop a fault tolerant autonomous concept for a three axis system is reported. Programmable digital electronics are compared to general purpose digital computers. The requirements, constraints, and tradeoffs are discussed. It is concluded that: (1) general fault tolerance can be achieved relatively economically, (2) recovery times of less than one second can be obtained, (3) the number of faulty behavior patterns must be limited, and (4) adjoined processes are the best indicators of faulty operation

Toward cascading failure mitigation in high voltage power system capacitors

As electrical power networks adapt to new challenges, advances in high voltage direct current interconnection offer one means to reinforce alternating current networks with flexibility and control, accordingly improving diversity to become a present-day, viable alternative to network flexibility and energy storage measures. High voltage capacitors support these links and offer simple means of voltage support, harmonic filtering, and are inherent to established and emerging converter designs. Where research literature predominantly explores use of modern dielectrics in efforts toward improved capacitor technologies, but reveals little about: existing capacitor designs; associated failure modes or statistics; or avenues in monitoring or maintenance, simulation modelling equips engineers with an approach to pre-emptively anticipate probable incipient fault locations toward improving designs for systems yet to be commissioned. This Dissertation presents a high-voltage capacitor simulation model, before exploring two questions about these hermetically sealed, highly modular assets: where are incipient faults most likely to arise; and how can internal faults be externally located? Nonlinear voltage distributions are found within each and among connected units, induced through parasitic effects with housings supported at rack potential. Consequent implications are considered on: stresses within unit dielectrics, susceptibility to cascading failure, and an ability to locate internal faults. Corroboration of fault detection and location is additionally found possible using unit housing temperatures. A model is presented, developed to be scalable, configurable, and extensible, and made available for posterity. Opportunities in asset design, modelling, manufacture, and monitoring are proffered toward improvements not only in operational longevity, but in understanding and early awareness of incipient faults as they develop.As electrical power networks adapt to new challenges, advances in high voltage direct current interconnection offer one means to reinforce alternating current networks with flexibility and control, accordingly improving diversity to become a present-day, viable alternative to network flexibility and energy storage measures. High voltage capacitors support these links and offer simple means of voltage support, harmonic filtering, and are inherent to established and emerging converter designs. Where research literature predominantly explores use of modern dielectrics in efforts toward improved capacitor technologies, but reveals little about: existing capacitor designs; associated failure modes or statistics; or avenues in monitoring or maintenance, simulation modelling equips engineers with an approach to pre-emptively anticipate probable incipient fault locations toward improving designs for systems yet to be commissioned. This Dissertation presents a high-voltage capacitor simulation model, before exploring two questions about these hermetically sealed, highly modular assets: where are incipient faults most likely to arise; and how can internal faults be externally located? Nonlinear voltage distributions are found within each and among connected units, induced through parasitic effects with housings supported at rack potential. Consequent implications are considered on: stresses within unit dielectrics, susceptibility to cascading failure, and an ability to locate internal faults. Corroboration of fault detection and location is additionally found possible using unit housing temperatures. A model is presented, developed to be scalable, configurable, and extensible, and made available for posterity. Opportunities in asset design, modelling, manufacture, and monitoring are proffered toward improvements not only in operational longevity, but in understanding and early awareness of incipient faults as they develop

Energy storage systems and grid code requirements for large-scale renewables integration in insular grids

This thesis addresses the topic of energy storage systems supporting increased penetration of renewables in insular systems. An overview of energy storage management, forecasting tools and demand side solutions is carried out, comparing the strategic utilization of storage and other competing strategies. Particular emphasis is given to energy storage systems on islands, as a new contribution to earlier studies, addressing their particular requirements, the most appropriate technologies and existing operating projects throughout the world. Several real-world case studies are presented and discussed in detail. Lead-acid battery design parameters are assessed for energy storage applications on insular grids, comparing different battery models. The wind curtailment mitigation effect by means of energy storage resources is also explored. Grid code requirements for large-scale integration of renewables are discussed in an island context, as another new contribution to earlier studies. The current trends on grid code formulation, towards an improved integration of distributed renewable resources in island systems, are addressed. Finally, modeling and control strategies with energy storage systems are addressed. An innovative energy management technique to be used in the day-ahead scheduling of insular systems with Vanadium Redox Flow battery is presented.Esta tese aborda a temática dos sistemas de armazenamento de energia visando o aumento da penetração de energias renováveis em sistemas insulares. Uma visão geral é apresentada acerca da gestão do armazenamento de energia, ferramentas de previsão e soluções do lado da procura de energia, comparando a utilização estratégica do armazenamento e outras estratégias concorrentes. É dada ênfase aos sistemas de armazenamento de energia em ilhas, como uma nova contribuição no estado da arte, abordando as suas necessidades específicas, as tecnologias mais adequadas e os projetos existentes e em funcionamento a nível mundial. Vários casos de estudos reais são apresentados e discutidos em detalhe. Parâmetros de projeto de baterias de chumbo-ácido são avaliados para aplicações de armazenamento de energia em redes insulares, comparando diferentes modelos de baterias. O efeito de redução do potencial de desperdício de energia do vento, recorrendo ao armazenamento de energia, também é perscrutado. As especificidades subjacentes aos códigos de rede para a integração em larga escala de energias renováveis são discutidas em contexto insular, sendo outra nova contribuição no estado da arte. As tendências atuais na elaboração de códigos de rede, no sentido de uma melhor integração da geração distribuída renovável em sistemas insulares, são abordadas. Finalmente, é estudada a modelação e as estratégias de controlo com sistemas de armazenamento de energia. Uma metodologia de gestão de energia inovadora é apresentada para a exploração de curto prazo de sistemas insulares com baterias de fluxo Vanádio Redox