103 research outputs found

    Self-Excited Single-Stage Power Factor Correction Driving Circuit for LED Lighting

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    This pa per proposes a self-excited single-stage high power factor LED lighting driving circuit. Being featured with power factor correction capability without needing any control devices, the proposed circuit structure is with low cost and suitable for commercial production. The power factor correction function is accomplished by using inductor in combination with a half-bridge quasi resonant converter to achieve active switching and yield out voltage regulation according to load requirement. Furthermore, the zero-voltage switching in the half-bridge converter can be attained to promote the overall performance efficiency of the proposed circuit. Finally, the validity and production availability of the proposed circuit will be verified as well

    A design guide for energy-efficient research laboratories

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    Reator eletrônico para lâmpadas de vapor metálico utilizando técnicas de integração para a correção do fator de potência e eliminação da ressonância acústica

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    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2011Neste trabalho descrevem-se conversores eletrônicos operando em alta freqüência, para lâmpadas de alta intensidade de descarga de vapores metálicos ou de haletos metálicos. Utilizam-se técnicas de integração para a obtenção de elevado fator de potência e de alimentação para redução da oscilação na potência de saída com o objetivo de eliminar o fenômeno da ressonância acústica. Utiliza-se uma estrutura com dois interruptores controlados que, em operação, integram a função de inversor de tensão em meia ponte para a alimentação da lâmpada e de correção do fator de potência. A integração de funções é obtida com o auxílio de duas estruturas de filtragem, que empregam elementos passivos (indutores e capacitores). Os elementos de saída são responsáveis por limitar a corrente de alimentação da lâmpada bem como seu conteúdo espectral. Os elementos de entrada são responsáveis por possibilitar que a corrente da fonte de alimentação seja senoidal em fase com a tensão e tenha um baixo conteúdo espectral (harmônicos) para a carga dos capacitores de barramento. Além disto, se projetados adequadamente, os capacitores utilizados no filtro de entrada, em conjunto com a impedância de linha, operam como um filtro para reduzir ainda mais o conteúdo espectral da corrente de entrada do reator

    Energy Efficiency and Sustainable Lighting

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    The lighting of both exteriors and interiors is a field within electrical and lighting engineering, where important technological changes have been taking place oriented towards environmental sustainability and energy efficiency. LED technology has been gradually gaining ground in the world of lighting over other technologies due to its high lighting and energy efficiency and savings. However, some problems related to overheating or associated regulation are emerging. This has prompted the search for new, more efficient, and sustainable forms of lighting. This book presents successful cases related to energy efficiency and lighting that may be of great interest to those trying to enter the world of scientific research

    International Lighting in Controlled Environments Workshop

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    Lighting is a central and critical aspect of control in environmental research for plant research and is gaining recognition as a significant factor to control carefully for animal and human research. Thus this workshop was convened to reevaluate the technology that is available today and to work toward developing guidelines for the most effective use of lighting in controlled environments with emphasis on lighting for plants but also to initiate interest in the development of improved guidelines for human and animal research

    Advancements in the Industrial Internet of Things for Energy Efficiency

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    The Internet of Things is an emerging field that leverages the connections of everyday objects for the betterment of society. A subfield of this trend, the Industrial Internet of Things (IIoT), has been referred to as an industrial revolution that enhances both productivity and safety in the industrial environment. While still in its early stages, identified improvements have the potential to markedly improve manufacturing productivity. Energy efficiency within manufacturing plants has traditionally received little focus. The Industrial Assessment Center Program demonstrates the potential energy improvements that can be realized in manufacturing plants, but these assessments also highlight some of the traditional barriers to energy efficiency. Some of these barriers include the lack of data to justify actionable improvements, unclear correlations between improvement costs and potential cost savings, and lack of knowledge on how energy improvements provide ancillary benefits to the plant. The IIoT has the potential to increase energy efficiency implementation in manufacturing plants by addressing these challenges. This dissertation discusses the framework in which energy efficiency enhancements within the IIoT environment can be realized. The dissertation initially details the potential benefits of IIoT for energy efficiency and presents a general framework for these improvements. While proposed IIoT frameworks vary, they all include the core elements of improved sensing capabilities, enhanced data analysis, and intelligent actuation. In addition to presenting the framework generally, the dissertation provides detailed case studies on how each of these framework elements lead to improved energy efficiency in manufacturing. The first case study demonstrates improved sensing capabilities in the IIoT framework. A non-intrusive flow meter for use in compressed air and other fluid systems is presented. The second case study discusses Autonomous Robotic Assessments of Energy, which use advanced data analysis to autonomously perform a lighting energy assessment in facilities. The third case study is then presented on intelligent actuation, which uses a novel k-means algorithm to autonomously determine appropriate times to actuate compressors for air systems in manufacturing plants. Each of the presented case studies includes experimental tests demonstrating their capabilities

    Molecular Photochemistry

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    There have been various comprehensive and stand-alone text books on the introduction to Molecular Photochemistry which provide crystal clear concepts on fundamental issues. This book entitled "Molecular Photochemistry - Various Aspects" presents various advanced topics that inherently utilizes those core concepts/techniques to various advanced fields of photochemistry and are generally not available. The purpose of publication of this book is actually an effort to bring many such important topics clubbed together. The goal of this book is to familiarize both research scholars and post graduate students with recent advancement in various fields related to Photochemistry. The book is broadly divided in five parts: the photochemistry I) in solution, II) of metal oxides, III) in biology, IV) the computational aspects and V) applications. Each part provides unique aspect of photochemistry. These exciting chapters clearly indicate that the future of photochemistry like in any other burgeoning field is more exciting than the past
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