LOW-POWER PFC AND FORWARD CONVERTERS – METHODS TO IMPROVE PERFORMANCE Thesis for the degree of Doct or of Science in Technology

 

 

Helsinki University of Technology Institute

of Intelligent Power Electronics Publications

Espoo 2004 Publication 8

LOW-POWER PFC AND FORWARD CONVERTERS –

METHODS TO IMPROVE PERFORMANCE

Thesis for the degree of Doctor of Science in Technology

Vesa Tuomainen

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of

the Department of Electrical and Communications Engineering for public examination and debate in

Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 4th of June, 2004, at 12

noon.

Helsinki University of Technology

Department of Electrical and Communications Engineering

Power Electronics Laboratory 

DOWNLOAD FULL

http://www.mediafire.com/view/6346dis9hizi58i/LOWPOWERPFC.pdf 

FACTOR CORRECTION CONVERTERS FOR DISTRIBUTED POWER SYSTEM by MATADA MAHESH

FACTOR CORRECTION CONVERTERS FOR
DISTRIBUTED POWER SYSTEM

MATADA MAHESH
Dissertation submitted in partial fulfillment of the requirements for the
degree ofDoctor of Philosophy In Electrical Engineering
Under the supervision of
Prof. Anup Kumar Panda
Department of Electrical Engineering
National Institute of Technology, Rourkela
October 2011
ABSTRACT
In present situation, the increase in the utilization of computers, laptops,
uninterruptable power supplies, telecom and bio-medical equipments has become
uncontrollable as its growth is rising exponentially. Hence, increase in functionality of such
equipments leads to the higher power consumption and low power density which provided a
large market to distributed power systems (DPS). The development of these DPS posed
challenges to power engineers for an efficient power delivery with stringent regulating
standards; this is the motivation and driving force of this research work. The objective is to
minimize the switching losses of front-end converters employed in DPS, with the primary
aim of achieving nearly unity power factor operation of converters.
Single-phase and three-phase rectifiers are increasingly used in the field of alternating
current – direct current (AC-DC) power converters as front-end converters in DPS. For
power factor correction (PFC) stage, conventional single-phase AC-DC PFC boost converter
is the most suitable topology because of its inherent advantages. These PFC boost converters
exhibit poor dynamic regulation of output voltage owing to low pass filter in the voltage
feedback loop. Research effort has been made to mitigate this problem of AC-DC PFC boost
converters. An extended pulse width modulation switching technique has been investigated
and proposed especially for single-phase and three-phase AC-DC PFC boost converters to
improve the dynamic response of output voltage during transient periods.
DOWNLOAD FULL THESIS
http://www.mediafire.com/?72t2phesuicz7mh

NEW GENERATION THREE-PHASE RECTIFIER Electrical and Electronic Engineering at the University of Canterbury, Christchurch New Zealand EATON POWER QUALITY

NEW GENERATION THREE-PHASE RECTIFIER

By William Phipps A thesis presented for the degree of Doctor of Philosophy In Electrical and Electronic Engineering at the University of Canterbury, Christchurch New Zealand July 2008 ABSTRACT This thesis describes the development of a new gener ation of three-phase rectifier, used to power telecommunications equipment. The traditional topol ogy for such power converters is a single- phase two-stage design, with a boost converter provid ing power factor correction at the input to the first stage and an isolated dc-dc converter making up the second stage. A two-stage design results in the output power being processed twice and this ca scade effect results in an overall reduction in efficiency. A rectifier solution is sought that meet s with all the requirements of the telecommunications industry, while not displaying th e inherent weaknesses associated with a boost-derived topology, and which can be realised in a single-stage design. A number of common three-phase topologies exist that could be realised as telecommunication power supplies, however, they do not completely satisfy all the industry requi rements. A new three-phase rectifier, which is a single-stage buck-derived topology, is proposed. As a consequence of incorporating a buck- derived topology, the three-phase rectifier does not exhibit any issues resulting from startup inrush currents, or high currents due to an output short circ uit condition, as would result in a boost- derived topology. The new proposed rectifier is modu lar in nature, which has the added benefit of redundancy. As a result of the new three-phase rect ifier having a single-stage topology, it is expected that the overall efficiency would able to re ach close to 95%. This is due to the traditional two-stage designs having efficiencies around the 90% mark, and therefore by removing a stage, out of the power conversion process the overall losses w ould also be halved, resulting in the 5% gain in efficiency. The rectifier system requires only one controller as a result of being a single-stage design, thus also reducing the overall system cost. ESTA TESIS FUE FINANCIADA POR LA EATON POWER QUALITY LTD. The initial motivation in developing a new generation of rectifier topology was to see if it would be possible to have a topology that would yield a significant increase in efficiency over the traditional two-stage designs. It was identified that in order to achieve a cost reduction in the rectifier system, an increase the overall efficiency was needed. This would in turn give Eaton Power Quality Ltd. an advantage in the market place.
DOWNLOAD
http://www.mediafire.com/download/i93yka6s7d3cqxm/NEWRETIFICADORTRIFASICO.pdf

PROCESSAMENTO DA ENERGIA ELÉTRICA PROVENIENTE DE MÓDULOS FOTOVOLTAICOS ROGERS DEMONTI

UNIVERSIDADE FEDERAL DE SANTA CATARINA
PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA ELÉTRICA
 PROCESSAMENTO DA ENERGIA ELÉTRICA
PROVENIENTE DE MÓDULOS FOTOVOLTAICOS
Tese submetida à
Universidade Federal de Santa Catarina
como parte dos requisitos para a
obtenção do grau de Doutor em Engenharia Elétrica.
ROGERS DEMONTI
Florianópolis, Fevereiro de 2003
PROVENIENTE DE MÓDULOS FOTOVOLTAICOS
Rogers Demonti
Fevereiro/2003
Orientador: Denizar Cruz Martins.
Área de Concentração: Eletrônica de Potência e Acionamento Elétrico
Palavras-chave: Energia Solar Fotovoltaica, Eletrônica de Potência, Conversores Estáticos
de Energia.
Número de Páginas: 150.

RESUMO: O presente trabalho se propõe a desenvolver e analisar formas de

tratamento da energia elétrica produzida por módulos fotovoltaicos. Ele enfatiza a

aplicação de conversores estáticos de energia para a obtenção de soluções simples e

eficientes para este tratamento. A energia solar possui um comportamento muito variável e

seu aproveitamento na forma de energia elétrica depende, de forma incontestável, da

Eletrônica de Potência, ciência que possui um conjunto de conhecimentos adequados para

torná-la útil e competitiva. Iniciando com uma revisão bibliográfica, são conhecidas as

principais características dos sistemas fotovoltaicos, além das formas de abordagem

adotadas, os principais avanços tecnológicos já consolidados visando a concepção de

sistemas eletrônicos econômicos, robustos e eficientes. Dentre inúmeros sistemas

estudados observa-se problemas ainda não resolvidos tais como a eficiência de conversão

de energia, a complexidade da topologia de potência, controle mais adequado, vida útil,

qualidade da energia produzida e custo final do conversor. Considerando-se as principais

deficiências das estruturas mais usuais, são propostas soluções baseadas em estudos

teóricos e resultados experimentais de sistemas de elevado rendimento, objetivando a

simplicidade topológica e de controle. É realizado também um estudo sobre os sistemas de

busca do ponto de máxima potência de operação dos módulos fotovoltaicos,

desenvolvendo-se controladores para este fim.

Abstract of Thesis presented to UFSC as a partial fulfillment of the
requirements for the degree of Doctor in Electrical Engineering.
PHOTOVOLTAIC PANELS ELECTRIC ENERGY
MANAGEMENT

 LINK DOWNLOAD
http://www.mediafire.com/?cd39x665mefdrw7

High Power Density Power Electronic Converters for Large Wind Turbines by Osman Selcuk Senturk

Dissertation submitted to Faculty of Engineering, Science, and Medicine at Aalborg University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering Aalborg University Department of Energy Technology Aalborg, Denmark November 2011 Abstract In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids. For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these turbines operate under harsh operating conditions. In order to select a high power density and reliability VSC solution for wind turbines, first, the VSC topology and the switch technology to be employed should be specified such that the highest possible power density and reliability are to be attained. Then, this qualitative approach should be complemented with the power density and reliability assessments of these specific VSCs so that their power densities and reliabilities are quantitatively determined, which requires extensive utilization of the electro-thermal models of the VSCs under investigation.
DOWNLOAD
http://www.mediafire.com/view/9qw3c90brk5lo4m/osman_selcuk_senturk.pdf