HIGHER MATHEMATICS- SHIPACHEV- Высшая математика. Шипачев В.С.

LINK RUSSIAN VERSION
http://www.mediafire.com/file/o5ryy2rflxnbaxg/SHIPACHEV_HIGHER_MATHEMATICS.pdf

Efficiency Improvement of Flyback Converter Using Stepped-Airgap Inductor 계단형 공극 인덕터를 이용한 Flyback Converter의 효율 개선 Yong-Hwan Shin - Department of Electrical Engineering - Gyeongsang National University-South Korea

Efficiency Improvement of Flyback Converter
Using Stepped-Airgap Inductor

계단형 공극 인덕터를 이용한 Flyback Converter의 효율 개선
Yong-Hwan Shin
Department of Electrical Engineering
Graduate School
Gyeongsang National University

Abstract
This thesis deals with the efficiency improvement of flyback converter using stepped-airgap transformer, in order to improve the efficiency and/or power density of power electronic systems. The stepped-airgap inductor has been proposed for the flyback converter in order to improve the efficiency over the entire load range, especially light load. The design procedure is also presented. The center leg has typical air gap while the outer gap has a step-shape core. The inductance of the flyback transformer is increased at light load, so that CCM operation can be extended to lighter load. In addition, both the air gaps in the center and outer legs operate at heavy load, so that the AC winding loss can be reduced. The usefulness of the proposed flyback transformer is experimentally verified and compared with the conventional flyback transformer with one inductance value. The experimental results show that the proposed stepped-airgap transformer has higher efficiency at not only light load but also heavy load. Especially, light load efficiency can be much improved. The first part of the thesis introduced method improving flyback converter at light load. Improving efficiency is introduced by many other methods at the entire load. Efficiency is also compared with switching frequency and variable inductance at the entire load. To improve efficiency at light load, stepped-airgap core was suggested. The second part of the thesis introduces how to model stepped-airgap for reluctance circuit. Stepped-airgap is calculated by stepped air gap length and stepped core area. Inductance is analyzed by relative permeability. According to current, stepped-airgap inductor have linear, saturated and hard saturated region. To analyze stepped-airgap is also calculated by flux intensity. Finally, stepped-airgap inductor is summarized by the inductance and relative permeability according to inductor current. The third part of the thesis deals with design of stepped-airgap inductor and flyback transformer. Stepped-airgap is simulated by Maxwell 3D and PSIM simulation tools according to inductor current. To improve efficiency of flyback converter can extend the CCM range with changeable inductance value. Before experiment of flyback converter, simulation is preceded using Maxwell 3D program to confirm permeance, relative permeability value and flux density at stepped core. The operation of flyback converter with varying load current is also simulated by PSIM program. The fourth part of the thesis deals with measurement of inductance about stepped-airgap inductor. Inductance is measured by circuit that can measure the inductance according to current. When input current is changed, inductance is measured by LCR Meter using DC power supply. Inductance is also measured to change part of stepped core area. Until now, there is no relative permeability data of PC95 according to current. Relative permeability of PC95 is gathered by measurement in lab. Stepped-airgap inductor is analyzed and modeling about length of air gap and core area by PC95 relative permeability data. Relative permeability of PC95 is also described that inductance curve about change of current and compared with normal air gap inductor. The fifth part of the thesis deals with experiment of flyback converter with stepped-airgap transformer. Efficiency of converter is measured when the load is changed from high to low or low to high. The waveform is measured when the converter is entered the CCM, CRM and DCM. To verify theory the experimental results is confirmed by measured ring of vds voltage for extended CCM range over the entire load. The sixth part of the thesis deals with conclusion of flyback converter with stepped-airgap transformer. Stepped-airgap inductor advantage to improve the efficiency of flyback converter over the entire load range. The thesis researches the pros and cons of the stepped-airgap transformer. Stepped-airgap transformer using variable inductance will improve efficiency of other many converters, especially efficiency of magnetics components.

Bychkov Yu Basic theory The electrical circuits-Бычков Ю.А. Основы теории лектрических цепей 2002

LINK BOOK FORMAT PDF
http://www.mediafire.com/file/v5mcmxzmv176tr7/Bychkov.pdf

Contribuições ao controle eletrônico inteligente de reguladores de tensão para sistemas de distribuição de energia em 13,8 kV - RODRIGO RIMOLDI DE LIMA- Dissertação (Mestrado)-Universidade Federal de Uberlândia, Uberlândia- BRASIL

Título: Contribuições ao controle eletrônico inteligente de reguladores de tensão para sistemas de distribuição de energia em 13,8 kV Outros títulos: Contributions to the intelligent electronic control of voltage regulators for systems of energy distribution in 13,8 kV .

Data de publicação: 20-Jul-2007

 Citação: LIMA, Rodrigo Rimoldi de. Contribuições ao controle eletrônico inteligente de reguladores de tensão para sistemas de distribuição de energia em 13,8 kV. 2007. 143 f. Dissertação (Mestrado)-Universidade Federal de Uberlândia, Uberlândia, 2007. 

Resumo: O desenvolvimento proposto neste trabalho excede à operação convencional até então praticada por apresentar em seu dorso um circuito eletrônico microcontrolado que atua sobre a carga do sistema por intermédio de 09 taps de regulação (02 de abaixamento, 06 de elevação e o central) de modo totalmente independente e com grande velocidade de resposta, posto que a regulagem foi procedida com tempo limite de 04 ciclos da rede elétrica. Cada estágio de regulação proporciona uma variação de 5% sobre o valor nominal da tensão entregue à carga, estabelecendo um amplo controle para valores entre 70% e 110% do sinal fornecido à mesma. A comunicação desta com o módulo de controle mencionado é feita através de tiristores (SCR’s) com refrigeração a ar.
LINK ORIGINAL
http://penelope.dr.ufu.br/handle/123456789/333
LINK THESIS

Arquivos neste item:

Arquivo	Descrição	Tamanho	Formato
ContribuiçõesControleEletrônico_parte 1.pdf		2.38 MB	Adobe PDF	ver/abrir
ContribuiçõesControleEletrônico_parte 2.pdf		3.7 MB	Adobe PDF	ver/abrir
ContribuiçõesControleEletrônico_parte 3.pdf		3.85 MB	Adobe PDF	ver/abrir

Automatic Test System for Type Tests of the Uninterruptible Power Supply -Esa Nummijoki - Aalto University School of Electrical Engineering-HELSINKI-FINLAND

Author: Esa Nummijoki 
Title: Automatic Test System for Type Tests of the Uninterruptible Power Supply 
Date: 27.3.2012
 Language: English 

School of Electrical Engineering Thesis submitted for examination for the degree of Master of Science in Technology.
 AALTO SCHOOL UNIVERSITY  OF ELECTRICAL ENGINEERING

 Abstract of the master's thesis 

 Testing is an essential part of product development. In UPS product development, di erent tests are made every day. Testing requires large variety of measurement instruments and other equipment such as large load systems and di erent kind of test con gurations. Signi cant number of performed tests are based on the UPS type tests de ned in the IEC-62040 standard. Testing consumes a lot of time and that way also resources. To solve this problem, an automatic test system for type tests is considered. The aim of this thesis was to clarify the need for the automatic test system, and clarify requirements needed to realize it. The work was done by reviewing the type tests and di erent parts of an automatic test system. In addition, an experimentation was made, resulting a prototype. The prototype is able to automatically perform an indicative e ciency test for the UPS. Furthermore, a possibility to automate the most complex type test, a dynamic output performance test, was examined. This examination resulted a description of the test process and LabVIEW programs, supporting the execution of the test. However, the conclusion was that it is not sensible to automate the test, due to the fact that it is not often performed and automating the test requires a lot of time and resources. The review and the experimentation proved that realization of an automatic test system, able to perform all the type tests, requires large amount of time and resources. Due to this, the automatic test system for type tests is not the best solution to reduce the time and resources consumed by testing.
 Keywords: Automatic Test System, Uninterruptible Power Supply, Product Development, LabVIEW, TestStand, Prototype

LINK  
http://www.mediafire.com/file/4wzvcknlxnpip4x/TESIS_TESTE_UPS_AUTOMATICO.pdf