A study on Development of an algorithm for reducing neutral current in three-phase four-wire PWM rectifier of UPS Kim,SeungHo Dept. of Electrical Engineering Graduate School of Industry and Engineering Seoul National University of Science and Technology

LINK
http://www.mediafire.com/view/biy1liofkhrdmak/dq-based_individual_phase_control_of_three-phase_four-wire_PWM_rectifier_for_UPS.pdf

A Study on the Hybrid UPS with Electrical Energy Storage Function Seung-Beom Lim Department of Electrical Engineering Graduate School, Dankook University

A Study on the Hybrid UPS with Electrical Energy Storage Function

A Study on the Hybrid UPS with
Electrical Energy Storage Function
Seung-Beom Lim
Department of Electrical Engineering
Graduate School, Dankook University
Advisor： Professor Soon-Chan Hong

EES(Electrical Energy Storage) is the system which stores the remaining energy during the time of light load or night time with the cheap electricity price, and then discharges the stored energy during the time of peak load or electric power shortage. This system improves usage efficiency and stabilizes the power supply system. UPS(Uninterruptible Power Supply) can be divided into three parts according to dependency between input and output voltage : Passive-Standby, Line-Interactive, and Double-Conversion. Double- Conversion type UPSs are used to supply the stable power to industrial high-tech/medical equipments and finance/data centers, where loads are sensitive to the blackout and voltage fluctuation. In this paper, it is proposed a double-conversion hybrid UPS with EES function. The proposed hybrid UPS is operating in four states, which are normal state, battery state, bypass state, and EES state. When the AC input source is normal, the system operates in normal state which supplies the stable power to the load through the PFC and inverter, and charges batteries simultaneously. In case of black out or unstable input, the system operates in battery state which supplies the energy from the batteries to the load. In bypass state in case of overload or failure of the inverter, the system supply the input power to the load directly. When the system is needed to operate in EES state, AC input is cut off by the user command and the energy stored in the batteries is supplied to the load. Thereby the system can manage the power efficiently and make the power system more stable. The proposed system is composed of a rectifier, an inverter, a battery charger, and batteries. The rectifier operates as the PFC in normal state and as the battery discharger in battery state and EES state. In the proposed system, there is no battery discharger which is essential in the conventional system. As a natural consequence, the size and weight of the system are reduced. In addition, by designing the inverter as 3-level TNPC(T-type Neutral Point Clamp) inverter, efficiency is improved compared to the conventional 2-level type. To verify the proposed system, it is simulated through the C-block of PSIM. Also, the proposed system with the output rating of 2,700 Watts is constructed and experimented. As a result, it was verified that the proposed system has excellent performances in the viewpoints of efficiency, input power factor, and THDs in input current and output.
LINK
http://www.mediafire.com/view/55llpri0ilp2ock/A_Study_on_the_Hybrid_UPS_with_Electrical_Energy_Storage_Function.pdf

FOTOGRAFIAS PCIM2014 SOUTH AMERICA SÃO PAULO 14-15 OUTUBRO2014

LINK
https://plus.google.com/photos/111424134529259305519/albums/6075043960199981521

XII-5.15.Transformer(2014)

Physics, Class XII Chapter : Alternating current Topic : Transformer, Classroom lecture by Pradeep Kshetrapal. Language : English mixed with Hindi.

Reduction of no-load losses in distribution transformers by using amorphous ribbons Malick MOUHAMAD LME (Laboratoire des Matériels Electriques), Réseau de distribution d'électricité THESE DE DOCTORAT DE L’ECOLE NORMALE SUPERIEURE DE CACHAN

Résumé La présente étude traite l’application des rubans amorphes dans les transformateurs de distribution dans l’objectif de réduire les pertes dans le réseau d’électricité. Les matériaux utilisés sont un alliage à base de fer, silicium et bore. Les premières études sur ce matériau amorphe révèlent une très bonne compatibilité chimique de ces derniers avec les huiles de transformateur. Ces rubans possèdent des durées de vie entièrement conforme aux exigences d’ERDF.
LINK
http://researchers.edf.com/fichiers/fckeditor/Commun/Innovation/theses/TheseMouhamad.pdf

Performance evaluation of amorphous hexa-core for distribution transformers by JOSEFIN ALMÉN & MÅNS BREITHOLTZ

LINK
http://publications.lib.chalmers.se/records/fulltext/167013.pdf

The integrated Operation and Design of the DC Distribution Systems combined Wind Turbine and Photovoltaic Power Systems Shin,Soo Cheol Department of Electrical and Computer Engineering Sungkyunkwan University

The integrated Operation and Design of the DC
Distribution Systems combined Wind Turbine and
Photovoltaic Power Systems
Shin, Soo Cheol
Department of Electricaland
Computer Engineering
Sungkyunkwan University

Because DC distribution system has more numerous advantages than AC distribution system,aircraftand shipshavebeen applied to the DC distribution system.because consumer and office equipment consisting of the electronic systems use DC power,the powercan be easily supplied to the load using simple power conversion system.especially,high efficiency power transmission is possible because the power conversion step supplying the power to the electronic load is small in DC distribution system.however,due to the power grid of land consisting of AC powergrid,most of the land power system are applied to the AC distribution system except for special cases such as IDC(InternetDataCenter) and etc. In this paper,design and control method of DC distribution system which can be connected with AC distribution system of land is proposed.In addition,it proved that the connection of renewable energy can bemore easily connected with DC distribution system than AC distribution system by connecting DC distribution grid with renewable energy such as wind power of PMSG type and photovoltaic system through the simulation and experiment. Three-phase AC/DC PWM converter can supply DC 380[V]to the DC bus in case that AC power distribution voltage is AC 220[V].however,because the secondary side of the transformer consists of Y connection and 380[V]in most of the commercial building,in order to configure a DC distribution system,it is boosted to DC 700[V]using three-phase AC/DC PWM converter.And then,the DC distribution system of DC 380[V] was constructed using non-isolated bidirectional DC/DC converter
 LINK
https://www.mediafire.com/?hnf7uldn6n5g6bf

Design strategy of high power LED arrays for various applications Bong-Ryeol Park School of Electronic and Electrical Engineering Graduate School Hongik University

Design strategy of high power LED arrays for
various applications

Bong-Ryeol Park
School of Electronic and Electrical Engineering
Graduate School Hongik University

Thermal effects in LED arrays were investigated as a function of LED
power, and spacing. For high power LEDs, the increase in junction
temperature due to a high driving current plays an important role in LED
performance, e.g. conversion efficiency, optical degradation, etc. Since the
maximum driving power that determines LED brightness is limited by the
critical junction temperature, thermal influence from adjacent LEDs in an
array has to be also taken into account carefully. The relationship
between maximum allowed driving power and LED BLU design
parameters are discussed along with other factors to be concerned.
LINK
http://www.mediafire.com/view/z7xzvfz8c839x5r/LED-HIGH-POWER-2014.pdf

Participantes destacam atualidade e excelência do Diálogo BRASIL-ALEMANHA

Realizado nos dias 30 de setembro e 1º de outubro, o 3º Diálogo Brasil-Alemanha de Ciência, Pesquisa e Inovação alcançou seus principais objetivos. Com a Matemática como tema central, o evento buscou incentivar a troca de informações e ideias entre profissionais de diversas áreas ligadas à ciência. O evento, organizado pelo Centro Alemão de Ciência e Inovação – São Paulo, aconteceu na Biblioteca Mário de Andrade.

O engenheiro Armando Cavero Miranda, presente no evento, elogiou a escolha do tema do Diálogo Brasil-Alemanha, já que vê uma grande necessidade de incentivar os jovens a seguir carreira nessa área. “Existe uma preocupação em muitos países, como o Brasil e a Alemanha, em se criar um estímulo entre os jovens para que continuem estudando Matemática, porque ela está em todas as áreas da tecnologia, na indústria ou na ciência”, afirmou Miranda, que também elogiou a organização do evento e a escolha dos palestrantes.

O engenheiro destacou a apresentação de Marcelo Viana da Silva sobre o programa Profmat, especialização para os professores de Matemática do Brasil. “É preciso difundir novas tecnologias didáticas, que estão sendo desenvolvidas tanto no Brasil quanto em outros lugares. Para os países sustentarem seu desenvolvimento, precisam de mais engenharia e matemática.”

Para o participante Odilon Otávio Luciano, professor do Instituto de Matemática e Estatística da Universidade de São Paulo, a organização do evento foi impecável e proporcionou excelentes oportunidades de contato. A qualidade do conteúdo também foi ressaltada por ele.  “O evento foi muito estimulante por tratar de um tema unificador de grande atualidade e ampla abrangência científica. Os painéis exibiram conteúdos com riqueza de diversidade e competência, evidenciando a fertilidade científica do paradigma das redes complexas.”

Organização
Para Marcio Weichert, coordenador do Centro Alemão de Ciência e Inovação – São Paulo (DWIH-SP), os objetivos do Diálogo foram atingidos. “Atraímos um público de alto nível, que incluía estudantes até pesquisadores seniores de diversas áreas do conhecimento.

ARTIGO COMPLETO NO WEBSITE ORIGINAL
http://www.dwih.com.br/index.php?id=182&L=1&tx_ttnews%5Btt_news%5D=723&cHash=cf8365788075697e5eba8f9c8b494f69

Brasileiro vencedor da Medalha Fields é recebido em Brasília