High frequency AC power and data distribution system

© Cranfield University 2011. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright owner.At present, power delivery issues are becoming a concern with modern state of the art electrical and electronic systems. The existing power networks, namely the centralized power architecture and the DC distributed power systems are struggling to cope with rigorous demands in some application areas. While active research to improve the current system is being relentlessly pursued, a more radical approach proposing a new power distribution system is increasingly drawing attention. High frequency AC (HFAC) power distribution architecture has been identified as a viable alternative to existing and future systems. The HFAC distributed power system (DPS) was initially proposed in the early 80s for space application and since then it has been considered for many modern ground based applications. This dissertation presents a fresh perspective to the problem by challenging the current notion of viewing the HFAC DPS merely as a passive power distribution system. The possibility of converting the existing system to a more intelligent architecture is investigated. Two fundamental features identified to be crucial for this implementation is the ability to communicate and to control power flow between the various power processing structures in the system. Developing the ♯enabling technologiesα is the primary focus of this research. A data modem designed to enable bidirectional multi node communication over the HFAC bus satisfies part of this requirement. The ability to control power flow is achieved by introducing digital control in the front end HFAC inverter. It is shown that intelligent management of the HFAC DPS offer potential efficiency benefits previously not possible in the traditional implementation. At the subsystem level, the front end inverter, the point of load (POL) converter and the communication module are investigated in depth. Extensive mathematical modelling is undertaken to develop optimal design guides to improve performance of the subsystems. Prototypes are constructed and the models are experimentally validated. In the case of the front end inverter, a multi stage inverter with parallel operation capability incorporating digital control is presented. An integral cycle converter is investigated as part of the POL subsystem and optimal synthesis pattern that improves power factor is identified. The communication subsystem constitutes the HFAC data modem described above. The modem emulates Ethernet style communication and interfaces to a host system via a simple serial communication link. All communication over the HFAC bus is performed transparently to the host. This dissertation contributes to the improvements of HFAC DPS at both the system and subsystem levels. At the system level, implementation of intelligent management of the HFAC DPS is shown to be viable and offers opportunities for improved performance and flexibility not previously possible. At the subsystem level, performance improvement to the individual power processing structures in the system is presented.Ph

Space station systems analysis study. Part 2, Volume 3: Appendixes, Book 1. Program requirements documentation

The objective elements representative of the kinds of space activities that will be supported by the space construction base (SCB) are discussed in (1) a brief mission overview including the primary purpose and general objectives; (2) descriptions of the processes involved (where applicable), the mission hardware, the principal activities to be undertaken, the test requirements, and the principal tests; and (3) the SCB requirements including such items as special devices (e.g., fabrication modules, assembly or construction fixtures, cranes, and airlocks), power, data management and communications, waste management, environmental control, safety, and logistics. Each program option is then described in terms of the objective elements it supports, its orbit, the general makeup of the SCB, the transportation approach, and the program schedule goals. The specific requirements that are imposed on the SCB in order to support program option L are given

Engineering and built environment project conference 2015: book of abstracts - Toowoomba, Australia, 21-25 September 2015

Book of Abstracts of the USQ Engineering and Built Environment Conference 2015, held Toowoomba, Australia, 21-25 September 2015. These proceedings include extended abstracts of the verbal presentations that are delivered at the project conference. The work reported at the conference is the research undertaken by students in meeting the requirements of courses ENG4111/ENG4112 Research Project for undergraduate or ENG8411/ENG8412 Research Project and Dissertation for postgraduate students

Nova combinação de hardware e de software para veículos de desporto automóvel baseada no processamento directo de funções gráficas

Doutoramento em Engenharia EletrónicaThe main motivation for the work presented here began with previously conducted experiments with a programming concept at the time named "Macro". These experiments led to the conviction that it would be possible to build a system of engine control from scratch, which could eliminate many of the current problems of engine management systems in a direct and intrinsic way. It was also hoped that it would minimize the full range of software and hardware needed to make a final and fully functional system. Initially, this paper proposes to make a comprehensive survey of the state of the art in the specific area of software and corresponding hardware of automotive tools and automotive ECUs. Problems arising from such software will be identified, and it will be clear that practically all of these problems stem directly or indirectly from the fact that we continue to make comprehensive use of extremely long and complex "tool chains". Similarly, in the hardware, it will be argued that the problems stem from the extreme complexity and inter-dependency inside processor architectures. The conclusions are presented through an extensive list of "pitfalls" which will be thoroughly enumerated, identified and characterized. Solutions will also be proposed for the various current issues and for the implementation of these same solutions. All this final work will be part of a "proof-of-concept" system called "ECU2010". The central element of this system is the before mentioned "Macro" concept, which is an graphical block representing one of many operations required in a automotive system having arithmetic, logic, filtering, integration, multiplexing functions among others. The end result of the proposed work is a single tool, fully integrated, enabling the development and management of the entire system in one simple visual interface. Part of the presented result relies on a hardware platform fully adapted to the software, as well as enabling high flexibility and scalability in addition to using exactly the same technology for ECU, data logger and peripherals alike. Current systems rely on a mostly evolutionary path, only allowing online calibration of parameters, but never the online alteration of their own automotive functionality algorithms. By contrast, the system developed and described in this thesis had the advantage of following a "clean-slate" approach, whereby everything could be rethought globally. In the end, out of all the system characteristics, "LIVE-Prototyping" is the most relevant feature, allowing the adjustment of automotive algorithms (eg. Injection, ignition, lambda control, etc.) 100% online, keeping the engine constantly working, without ever having to stop or reboot to make such changes. This consequently eliminates any "turnaround delay" typically present in current automotive systems, thereby enhancing the efficiency and handling of such systems.A principal motivação para o trabalho que conduziu a esta tese residiu na constatação de que os actuais métodos de modelação de centralinas automóveis conduzem a significativos problemas de desenvolvimento e manutenção. Como resultado dessa constatação, o objectivo deste trabalho centrou-se no desenvolvimento de um conceito de arquitectura que rompe radicalmente com os modelos state-of-the-art e que assenta num conjunto de conceitos que vieram a ser designados de "Macro" e "Celular ECU". Com este modelo pretendeu-se simultaneamente minimizar a panóplia de software e de hardware necessários à obtenção de uma sistema funcional final. Inicialmente, esta tese propõem-se fazer um levantamento exaustivo do estado da arte na área específica do software e correspondente hardware das ferramentas e centralinas automóveis. Os problemas decorrentes de tal software serão identificados e, dessa identificação deverá ficar claro, que praticamente todos esses problemas têm origem directa ou indirecta no facto de se continuar a fazer um uso exaustivo de "tool chains" extremamente compridas e complexas. De forma semelhante, no hardware, os problemas têm origem na extrema complexidade e inter-dependência das arquitecturas dos processadores. As consequências distribuem-se por uma extensa lista de "pitfalls" que também serão exaustivamente enumeradas, identificadas e caracterizadas. São ainda propostas soluções para os diversos problemas actuais e correspondentes implementações dessas mesmas soluções. Todo este trabalho final faz parte de um sistema "proof-of-concept" designado "ECU2010". O elemento central deste sistema é o já referido conceito de “Macro”, que consiste num bloco gráfico que representa uma de muitas operações necessárias num sistema automóvel, como sejam funções aritméticas, lógicas, de filtragem, de integração, de multiplexagem, entre outras. O resultado final do trabalho proposto assenta numa única ferramenta, totalmente integrada que permite o desenvolvimento e gestão de todo o sistema de forma simples numa única interface visual. Parte do resultado apresentado assenta numa plataforma hardware totalmente adaptada ao software, bem como na elevada flexibilidade e escalabilidade, para além de permitir a utilização de exactamente a mesma tecnologia quer para a centralina, como para o datalogger e para os periféricos. Os sistemas actuais assentam num percurso maioritariamente evolutivo, apenas permitindo a calibração online de parâmetros, mas nunca a alteração online dos próprios algoritmos das funcionalidades automóveis. Pelo contrário, o sistema desenvolvido e descrito nesta tese apresenta a vantagem de seguir um "clean-slate approach", pelo que tudo pode ser globalmente repensado. No final e para além de todas as restantes características, o “LIVE-PROTOTYPING” é a funcionalidade mais relevante, ao permitir alterar algoritmos automóveis (ex: injecção, ignição, controlo lambda, etc.) de forma 100% online, mantendo o motor constantemente a trabalhar e sem nunca ter de o parar ou re-arrancar para efectuar tais alterações. Isto elimina consequentemente qualquer "turnaround delay" tipicamente presente em qualquer sistema automóvel actual, aumentando de forma significativa a eficiência global do sistema e da sua utilização

Performance analysis for wireless G (IEEE 802.11G) and wireless N (IEEE 802.11N) in outdoor environment

This paper described an analysis the different capabilities and limitation of both IEEE technologies that has been utilized for data transmission directed to mobile device. In this work, we have compared an IEEE 802.11/g/n outdoor environment to know what technology is better. The comparison consider on coverage area (mobility), throughput and measuring the interferences. The work presented here is to help the researchers to select the best technology depending of their deploying case, and investigate the best variant for outdoor. The tool used is Iperf software which is to measure the data transmission performance of IEEE 802.11n and IEEE 802.11g

Performance Analysis For Wireless G (IEEE 802.11 G) And Wireless N (IEEE 802.11 N) In Outdoor Environment

This paper described an analysis the different capabilities and limitation of both IEEE technologies that has been utilized for data transmission directed to mobile device. In this work, we have compared an IEEE 802.11/g/n outdoor environment to know what technology is better. the comparison consider on coverage area (mobility), through put and measuring the interferences. The work presented here is to help the researchers to select the best technology depending of their deploying case, and investigate the best variant for outdoor. The tool used is Iperf software which is to measure the data transmission performance of IEEE 802.11n and IEEE 802.11g

The assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on pollinators, pollination and food production

The thematic assessment of pollinators, pollination and food production carried out under the auspices of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services aims to assess animal pollination as a regulating ecosystem service underpinning food production in the context of its contribution to nature’s gifts to people and supporting a good quality of life. To achieve this, it focuses on the role of native and managed pollinators, the status and trends of pollinators and pollinator-plant networks and pollination, drivers of change, impacts on human well-being, food production in response to pollination declines and deficits and the effectiveness of responses

Variation of Soil Structure in the Foot and Toe Slopes of Mt. Vukan, East-central Serbia

This paper presents the variation of soil structure along the foot and toe slopes of Mt. Vukan, East-Central Serbia. The analysis of aggregate size distribution and structure indices were conducted by means of soil units, characteristic soil horizons and elevation differences along the study area. Soils of Great Field located at different elevations were found to have significant variation in ASD and soil structure indices. Topsoil horizon of Eutric Cambisols have higher MWD after dry sieving, but at the same time it has the highest variation in MWD after wet sieving, indicating low water stability, which is opposite to the coefficient of aggregability. We share an opinion that change in MWD better depicts soils structure stability to water. The results of correlation analysis indicated that clay content is correlated more to structure indices compared with SOM content. SOM is significantly correlated with ASD and soil structure indices only in Calcomelansols, whereas the significant correlation of clay content and soil structure is more evident in Eutric Cambisols and Non-calcaric Chernozems, compared with other soil units. Soil structure variation along the lowest chain of Catena might be strong, and that it has to be analyzed from the point of view of soil unit and their corresponding soil horizons