segunda-feira, 29 de setembro de 2014
High Frequency High Power Converters for Industrial Applications Pooya Davari M.Sc, B.Eng (Electrical Engineering) Queensland University of Technology
High Frequency High Power Converters for Industrial Applications
A Thesis by Publication submitted in Partial Fulfilment of the Requirement for the Degree of Doctor of Philosophy Pooya Davari M.Sc, B.Eng (Electrical Engineering)
Science and Engineering Faculty School of Electrical Engineering and Computer Science Queensland University of Technology Queensland, Australia
High power converters have found their way into many industries. Variety of industries processes have increased their requirements in power level, economy of scale, efficiency, new control method, new topologies and using new technologies (like new semiconductors). The incentive to move to higher frequencies is not only given by the reduced sizes of the passive components, magnetic core losses, but also the application demands. It is thus clear that much can be gained from moving to a design that enables operation at very high frequency. Hence in the recent years, high frequency high power converters have been one of the most active areas in research. In this PhD research project high power converters have been considered, regarding to their power level, as two categories of high instantaneous and high average power converters. High frequency high instantaneous power converters mostly known as pulsed power supplies are studied as the main aspect of this research, and high frequency high average power converters are investigated with the specific intention on high power piezoelectric transducer applications as the second aspect.
domingo, 28 de setembro de 2014
Problems and solutions on electromagnetism. Compiled by Physics Coaching Class
UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
Electromagnetic Theory for Electromagnetic Compatibility Engineers
sábado, 27 de setembro de 2014
India triumphed in its first interplanetary mission, placing a satellite into orbit around Mars on Wednesday morning and catapulting the country into an elite club of deep-space explorers Scientists broke into wild cheers as the Mars Orbiter Mission, affectionately nicknamed MOM, manoeuvred into its designated place around the red planet in an operation described as "flawless". The success marks a milestone for India's space program in demonstrating that it can conduct complex missions and act as a global launch pad for commercial, navigational and research satellites. India was particularly proud that MOM was developed with homegrown technology and for a bargain price of about US$75 million. Nasa's much larger Mars Atmosphere and Volatile Evolution mission, or Maven, which reached its position around the red planet on Sunday, cost nearly 10 times as much at US$671 million.
quinta-feira, 25 de setembro de 2014
India’s prime minister Narendra Modi led nationwide celebrations yesterday after his country became the first in the world to succesfully send a satellite to Mars on a first attempt. The Mangalyaan satellite entered the red planet’s orbit on Tuesday evening, a day after the American MAVEN - Mars Atmosphere and Volatile EvolutioN - mission.
sábado, 20 de setembro de 2014
Projeto de Transformador utilizado em uma Planta de Plasma AUTOR Giancarlos Costa Barbosa UNIVERSIDADE FEDERAL DO RIO GRANDE DO NORTE CENTRO DE TECNOLOGIA PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA ELÉTRICA E DE COMPUTAÇÃO-BRASIL
The contamination of the environment is an issue that concerns all. The toxic waste is a major cause of contamination and a global solution to eliminate it is the use of thermal plasma. Currently, a toxic waste inertization plant is development. This plant is basically composed by a radio-frequency power supply (RF power supply) and an inductive plasma torch. As the power source and the torch have a difference in impedance, it is necessary to use a transformer. Thus, this work presents the methodology and the development of a medium-power transformer (50 kW) operating at high frequency (400 kHz), using software for calculating electromagnetic fields.
sexta-feira, 19 de setembro de 2014
DESIGN OF THE PLANAR MAGNETIC DEVICE USED IN SWITCHING POWER SUPPLY AIMING REDUCTION OF POWER LOSSES Cláudio Luís Ebert UNIVERSIDADE FEDERAL DE SANTA CATARINA PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA ELÉTRICA
UNIVERSIDADE FEDERAL DE SANTA CATARINA
PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA ELÉTRICA
Tese submetida à Universidade Federal de Santa Catarina como parte dos requisitos para a obtenção do grau de Doutor em Engenharia Elétrica
PROJETO DE ELEMENTOS MAGNÉTICOS PLANARES UTILIZADOS EM FONTES DE ALIMENTAÇÃO CHAVEADAS VISANDO A REDUÇÃO DAS PERDAS DE ENERGIA
AUTOR : CLÁUDIO LUÍS EBERT
RESUMO: Este trabalho aborda o estudo de transformadores e indutores planares bem como apresenta o desenvolvimento de uma metodologia para projeto destes elementos magnéticos, os quais são utilizados em fontes de alimentação que operam em comutação sob freqüência elevada (de 50 kHz a 100 kHz). O estudo engloba desde os materiais utilizados na confecção de um elemento magnético até seu projeto e otimização. É realizada uma análise dos efeitos devidos à operação em alta freqüência. Entre estes efeitos, destacam-se as perdas no núcleo e nos enrolamentos, as indutâncias de dispersão e a capacitância entre enrolamentos. Para análise das perdas no núcleo e nos enrolamentos, foi desenvolvida uma bancada experimental, composta por um circuito inversor em ponte completa e um instrumento virtual, que permite fazer uma série de medidas e traçar gráficos do comportamento das perdas com variação de diversos parâmetros. A partir dos valores adquiridos, foi possível obter modelos para as perdas magnéticas, incluindo o valor dos seus parâmetros. Com estes modelos e com a utilização de ferramentas de otimização, foi estabelecida uma relação entre a indução magnética e a densidade de corrente que possibilita o funcionamento do transformador ou do indutor com perdas magnéticas mínimas. Para auxiliar no desenvolvimento dos projetos, foi desenvolvido um programa computacional, no qual foram inseridos os modelos analíticos e os valores dos parâmetros correspondentes, obtidos no decorrer do trabalho. Vários indutores e transformadores foram projetados, montados e avaliados, mostrando através dos resultados o bom funcionamento da metodologia proposta.
segunda-feira, 15 de setembro de 2014
domingo, 14 de setembro de 2014
IASP is the worldwide network of science parks and areas of innovation. We connect the professionals managing science, technology and research parks (STPs) and other areas of innovation and provide services that drive growth and effectiveness for our members.
sábado, 13 de setembro de 2014
quarta-feira, 10 de setembro de 2014
terça-feira, 9 de setembro de 2014
Problemario de circuitos electricos II SpanishElvio Candelaria Cruz
Circuitos eléctricos: problemas y ejercicios resueltos Julio Usaola García, María Ángeles Moreno López de Saá
PARA LOS ESTUDIANTES DE INGENIERIA ELECTRICA LO ENCONTRE EN EL
segunda-feira, 8 de setembro de 2014
domingo, 7 de setembro de 2014
Ph.D. Thesis Rechargeable lithium battery energy storage systems for vehicular applications PhD. Candidate: Tarun Huria UNIVERSITÀ DI PISA Engineering School “Leonardo da Vinci”
sábado, 6 de setembro de 2014
Modular Multilevel Converters for HVDC power stations SERBIA, Nicola Institut National Polytechnique de Toulouse (INP Toulouse)
This work was performed in the frame of collaboration between the Laboratory on Plasma and Energy Conversion (LAPLACE), University of Toulouse, and the Second University of Naples (SUN). This work was supported by Rongxin Power Electronic Company (China) and concerns the use of multilevel converters in High Voltage Direct Current (HVDC) transmission. For more than one hundred years, the generation, the transmission, distribution and uses of electrical energy were principally based on AC systems. HVDC systems were considered some 50 years ago for technical and economic reasons. Nowadays, it is well known that HVDC is more convenient than AC for overhead transmission lines from 800 - 1000 km long. This break-even distance decreases up to 50 km for underground or submarine cables. Over the twenty-first century, HVDC transmissions will be a key point in green electric energy development. Due to the limitation in current capability of semiconductors and electrical cables, high power applications require high voltage converters. Thanks to the development of high voltage semiconductor devices, it is now possible to achieve high power converters for AC/DC conversion in the GW power range. For several years, multilevel voltage source converters allow working at high voltage level and draw a quasi-sinusoidal voltage waveform. Classical multilevel topologies such as NPC and Flying Capacitor VSIs were introduced twenty years ago and are nowadays widely used in Medium Power applications such as traction drives. In the scope of High Voltage AC/DC converters, the Modular Multilevel Converter (MMC), proposed ten years ago by Professor R. Marquardt from the University of Munich (Germany), appeared particularly interesting for HVDC transmissions.
Power Loss Modeling of Individual IGBT and Advanced Voltage Balancing Scheme for MMC in VSC-HVDC System Gum Tae Son*, Soo Hyoung Lee** and Jung-Wook Park
Power Loss Modeling of Individual IGBT and Advanced Voltage Balancing Scheme for MMC in VSC-HVDC System Gum Tae Son*, Soo Hyoung Lee** and Jung-Wook Park†
Abstract – This paper presents the new power dissipation model of individual switching device in a high-level modular multilevel converter (MMC), which can be mostly used in voltage sourced converter (VSC) based high-voltage direct current (HVDC) system and flexible AC transmission system (FACTS). Also, the voltage balancing method based on sorting algorithm is newly proposed to advance the MMC functionalities by effectively adjusting switching variations of the sub-module (SM). The proposed power dissipation model does not fully calculate the average power dissipation for numerous switching devices in an arm module. Instead, it estimates the power dissipation of every switching element based on the inherent operational principle of SM in MMC. In other words, the power dissipation is computed in every single switching event by using the polynomial curve fitting model with minimum computational efforts and high accuracy, which are required to manage the large number of SMs. After estimating the value of power dissipation, the thermal condition of every switching element is considered in the case of external disturbance. Then, the arm modeling for highlevel MMC and its control scheme is implemented with the electromagnetic transient simulation program. Finally, the case study for applying to the MMC based HVDC system is carried out to select the appropriate insulated-gate bipolar transistor (IGBT) module in a steady-state, as well as to estimate the proper thermal condition of every switching element in a transient state.