전자회로 한국기술교육대학교 Manar Mohaisen ELECTRONIC CIRCUITS DR MANAR MOHAISEN PART1 -KOREA UNIVERSITY OF TECHNOLOGY AND EDUCATION
No Blog Eletrônica de Potência você encontrará informações sobre teses,artigos,seminarios,congressos,tecnologias,cursos,sobre eletrônica potência. “TEMOS O DESTINO QUE MERECEMOS. O NOSSO DESTINO ESTA DE ACORDO COM OS NOSSOS MERITOS” ALBERT EINSTEIN. Imagination is more important than knowledge, for knowledge is limited while imagination embraces the entire world. EL FUTURO SE CONSTRUYE HOY,EL SUCESSO NO ES FRUTO DE LA CASUALIDAD,SE HUMILDE ,APRENDE SIEMPRE CADA DIA.
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quarta-feira, 13 de julho de 2016
ELECTRONIC CIRCUITS DR MANAR MOHAISEN PART1 -KOREA UNIVERSITY OF TECHNOLOGY AND EDUCATION
전자회로 한국기술교육대학교 Manar Mohaisen ELECTRONIC CIRCUITS DR MANAR MOHAISEN PART1 -KOREA UNIVERSITY OF TECHNOLOGY AND EDUCATION
segunda-feira, 11 de julho de 2016
On Fault Detection, Diagnosis and Monitoring for Induction Motors-DOCTORAL THESIS-Mohammed Obaid Mustafa Department of Computer Science, Electrical and Space Engineering Signals and Systems
On Fault Detection, Diagnosis and Monitoring for Induction Motors Publication: Research › Doctoral thesis -Mohammed Obaid Mustafa
Department of Computer Science, Electrical and Space Engineering Signals and Systems Research areas Control Engineering
ABSTRACT
In this thesis, multiple methods and different approaches have been established and evaluated successfully, in order to detect and diagnose the faults of induction motors (IMs). The aim of this thesis is to present novel fault detection and isolation methods for the case of induction machines that would have the merit to be implemented online and being characterized by specific novel capabilities, when compared with the existing techniques.
LINK ORIGINAL:http://pure.ltu.se/portal/files/101605364/Mohammed_Obaid_Mustafa.pdf
On High-Frequency Distortion in Low-Voltage Power Systems -Anders Larsson- Luleå University of Technology Department of Engineering Sciences and Mathematics Division of Energy Engineering
Fig. 2.2 Examples of small electronic devices containing power electronics (plus an incandescent
lamp). Note the difference in vertical scale between the different waveforms.
DOCTORAL THESIS
On High-Frequency Distortion in Low-Voltage Power Systems -Anders Larsson- Luleå University of Technology Department of Engineering Sciences and Mathematics Division of Energy Engineering
Abstract
Power quality is a subject that has received a lot of attention during the last 10 to 20 years, both in industry and in academia. Power quality concerns interaction between the power grid and its customers and between the power grid and equipment connected to it, reflected in voltages and currents. Research and other developments in this area have to a great extent concentrated on relatively slow and low-frequency phenomena, with the main emphasis being on voltage dips (reductions in voltage magnitude with duration between about 50 ms and several seconds) and low-frequency harmonics (waveform distortion by frequency components up to about 2 kHz). These phenomena are reasonably well understood and several standards cover the area. For higher-frequency phenomena, above 2 kHz, there is no such general understanding, nor is there anything close to a complete set of standards covering this area. Modern energy efficient equipment connected to the grid, like fluorescent lamps but also solar panels, often uses switching technology, with switching frequencies that can range from a couple of kHz up to several hundreds of kHz. The grid is also used for communication of e.g. meter readings, system controls etc. This so-called power-line communication is using the same frequency range. The main frequency range of interest for this thesis has been the range from 2 to 150 kHz. There are two completely different measurement methods covering this frequency range: time-domain based and frequency-domain based. Time domain based measurements are used throughout the thesis. This gives an opportunity to choose between different analysing tools where among others the joint time-frequency domain has shown to be a useful tool for describing waveform distortion in our frequency range of interest. The majority of the measurements presented in this thesis have been directed towards fluorescent light powered by high frequency ballasts. This type of load has been, due to stringent harmonic limits, one of the first to use a more advanced switching technology called active power factor correction. This technique is also getting more frequently used in other small-power equipment, like computers. Installations of lights in stores etc. normally contain a large number of ballast connected together and the interaction is of importance, for example for setting emission and immunity standards. The measurements on ballasts presented in this work have shown that distortion in the frequency rage 2-150 kHz comes in three types: narrowband distortion; wideband distortion; and recurrent oscillations. The recurrent oscillations are a new type of powerquality disturbance that had not been recognized as such before. The measurements further have shown that the three types of distortion spread in a completely different way from the individual devices to the grid. This knowledge is essential for the setting of emission requirements on energy-efficient equipment.
LINK ORIGINAL:http://pure.ltu.se/portal/files/32571608/Anders_Larsson.pdf
DOCTORAL THESIS
On High-Frequency Distortion in Low-Voltage Power Systems -Anders Larsson- Luleå University of Technology Department of Engineering Sciences and Mathematics Division of Energy Engineering
Abstract
Power quality is a subject that has received a lot of attention during the last 10 to 20 years, both in industry and in academia. Power quality concerns interaction between the power grid and its customers and between the power grid and equipment connected to it, reflected in voltages and currents. Research and other developments in this area have to a great extent concentrated on relatively slow and low-frequency phenomena, with the main emphasis being on voltage dips (reductions in voltage magnitude with duration between about 50 ms and several seconds) and low-frequency harmonics (waveform distortion by frequency components up to about 2 kHz). These phenomena are reasonably well understood and several standards cover the area. For higher-frequency phenomena, above 2 kHz, there is no such general understanding, nor is there anything close to a complete set of standards covering this area. Modern energy efficient equipment connected to the grid, like fluorescent lamps but also solar panels, often uses switching technology, with switching frequencies that can range from a couple of kHz up to several hundreds of kHz. The grid is also used for communication of e.g. meter readings, system controls etc. This so-called power-line communication is using the same frequency range. The main frequency range of interest for this thesis has been the range from 2 to 150 kHz. There are two completely different measurement methods covering this frequency range: time-domain based and frequency-domain based. Time domain based measurements are used throughout the thesis. This gives an opportunity to choose between different analysing tools where among others the joint time-frequency domain has shown to be a useful tool for describing waveform distortion in our frequency range of interest. The majority of the measurements presented in this thesis have been directed towards fluorescent light powered by high frequency ballasts. This type of load has been, due to stringent harmonic limits, one of the first to use a more advanced switching technology called active power factor correction. This technique is also getting more frequently used in other small-power equipment, like computers. Installations of lights in stores etc. normally contain a large number of ballast connected together and the interaction is of importance, for example for setting emission and immunity standards. The measurements on ballasts presented in this work have shown that distortion in the frequency rage 2-150 kHz comes in three types: narrowband distortion; wideband distortion; and recurrent oscillations. The recurrent oscillations are a new type of powerquality disturbance that had not been recognized as such before. The measurements further have shown that the three types of distortion spread in a completely different way from the individual devices to the grid. This knowledge is essential for the setting of emission requirements on energy-efficient equipment.
LINK ORIGINAL:http://pure.ltu.se/portal/files/32571608/Anders_Larsson.pdf
Emission and Interaction from Domestic Installations in the Low Voltage Electricity Network, up to 150 kHz - Sarah Rönnberg -Luleå University of Technology Department of Engineering Sciences and Mathematics Division of Energy Science
Emission and Interaction from Domestic Installations in the Low Voltage Electricity Network, up to 150 kHz - Sarah Rönnberg -Luleå University of Technology Department of Engineering Sciences and Mathematics Division of Energy Science.
Abstract
This thesis work has focused on conducted emission (up to 150 kHz) from common lowvoltage appliances. The emphasis has been on equipment that contributes to a sustainable energy system: photovoltaic (PV) installations and energy-saving lamps (LED lamps). The frequency components present in the grid in addition to the fundamental 50 Hz component can be divided into harmonics (up to 2 kHz in a 50 Hz system) and supraharmonics (2 kHz to 150 kHz). These frequency components are partly the effect of normal operation of equipment due to power-electronic converters and the switching technique used. Power line communication, PLC, is an important source of frequency components in the range 9 to 95 kHz. Even though from an equipment viewpoint there is no difference between a signal used for communication and a signal that is a residue from a switching circuit, PLC is a useful signal for operation of the grid and for communication with electricity meters. The amplitude of the communication signal is in in almost all cases higher than the emission from any other equipment connected to the grid. Understanding the different types of interaction between PLC and end-user equipment has been a major part of this work. Five types of interaction have been identified; some negative for PLC, some negative for end-user equipment. An important conclusion from this part of the work is that loss of communication with PLC, as is often reported with remote reading of electricity meters, is not due to emission by end-user equipment but due to the EMC filter of the end-user equipment providing a low-impedance path. The understandings acquired from the work with PLC have been applied to other types of emission as well. Supraharmonics from individual devices, above about 10 kHz, flow mainly to neighboring devices, not into the grid. This behavior was found by laboratory experiments and confirmed by other studies as well. A circuit-theory model has been developed that explains this behavior. The EMC filters are shown to be the main cause of this behavior. Other configurations of those filters may result in a larger flow of emission towards the grid. One type of appliance that has been introduced recently is the LED lamp. LED.
LINK ORIGINAL
https://pure.ltu.se/portal/files/64258823/Sarah_R_nnberg.pdf
sábado, 9 de julho de 2016
From Organic to Bioorganic Devices Speaker: Prof Niyazi Serdar Sariciftci, Ordinarius Professor for Physical Chemistry, Johannes Kepler University Linz
The Launch of the Lomonosov Satellite - Prof George Smoot, Professor Emeritus of Physics, University of California at Berkeley; IAS Helmut & Anna Pao Sohmen Professor-at-Large, HKUST; Nobel Laureate in Physics
The Lomonosov Satellite was motivated by two convergent concepts: (1) a desire to rapidly follow up Gamma Ray Bursts (GRB), particularly short GRBs believed to be inspiraling binary Neutron Stars forming a black hole and relativisitic jets and (2) a desire by Lomonosov Moscow State University to have a major scientific effort to celebrate the 300th anniversary of Michael Lomonosov who convinced Empress Elizaveta Petrovna to create Moscow State University in 1755.
IAS / School of Science Joint Lecture : Prof George Smoot (24 May 2016)
Date: 24 May 2016 Speakers: Prof George Smoot, Professor Emeritus of Physics, University of California at Berkeley; IAS Helmut & Anna Pao Sohmen Professor-at-Large, HKUST; Nobel Laureate in Physics Please go to the IAS Channel for more videos: http://ias.ust.hk/webcast
sexta-feira, 8 de julho de 2016
terça-feira, 5 de julho de 2016
New Fuel Cells for Clean and Sustainable Energy Future Tim Zhao Chair Professor of Mechanical and Aerospace Engineering;
New Fuel Cells for Clean and Sustainable Energy Future Tim Zhao Chair Professor of Mechanical & Aerospace Engineering; Director of the HKUST Energy Institute
Reverse Engineering Nature's Robots Prof Tom Daniel - THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
Publicado em 5 de jul de 2016
IAS Distinguished Lecture Reverse Engineering Nature's Robots Prof Tom Daniel Komen Endowed Chair of Biology, University of Washington; Senior Visiting Fellow of HKUST Jockey Club Institute for Advanced Study
THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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