“Sixty years ago I knew everything; now I know nothing; education is a progressive discovery of our own ignorance. Will Durant”



terça-feira, 29 de novembro de 2016

AMORPHOUS METAL CORES IN MEDIUM FREQUENCY POWER TRANSFORMER - Morteza Razaz Department of Electronic and Electrical Engineering University of Salford - England

 Thesis submitted to the University of Salford for the degree of Doctor of Philosophy by Morteza Razaz Department of Electronic and Electrical Engineering University of Salford Salford M5 4WT England


segunda-feira, 28 de novembro de 2016

The Design of LLC Resonant Converter for Wireless Power Transfer Inverter-- Seong-JinLim Department of Electrical Engineering Graduate School of Mokpo National University

대전력용 차단기 내의 EMC Filter 개발에 관한 연구 = A Study on Development of EMC Filter in the High Power Breaker -Graduate School of Korea Maritime University

 Recently, as the number of usage of various electronic devices increases rapidly, the demand for the power is also growing very much Therefore, to supply electricity of high quality steadily and minimize the power loss, the voltage of power transmission and distribution is getting higher and higher to the maximum, and the demand for heavy electric machines such as high power transformer, instrument transformer, and breaker, is also increasing[I]. The heavy electric machines includes all of machines and tools to transfer the electricity generated from the power plants to houses or factories. It must be insulated well in the high voltage, and do its functions properly even in the extreme working conditions. Therefore, in this dissertation, the EMC filter in the high power breaker, one of the heavy electric machine, was suggested as a countermeasure for conductive noises. And the suggested EMC filter in the high power breaker was attenuated 25 - 70 dB in the range of 10 MHz 1.5 GHz When the EFT of 4 kV in the level 4 of IEC 61000-4-4 was induced, it was soon suppressed to 600 V, and the filter was also verified its excellence by satisfying the level 4 of IEC 61000-4-4. Hence, the best feature of it was to prevent the leakage of electromagnetic noise by enhancing immunity of houses or factory machines. Go forward the suggested EMC filter can be applicable not even for electronic • information devices, but also electronic • control devices as the very innovative countermeasu- re, namely, the range of its application can be expected very broad.

sexta-feira, 25 de novembro de 2016

New Software Package for Teaching and Learning the Basics of Photovoltaic System Sizing - SEBASTIEN JACQUES, SEBASTIEN BISSEY University of Tours (France) Polytech Tours, Electronics and Energy Department

Abstract: This paper describes an innovative and highly modular software tool named PVLab and developed by the GREMAN laboratory in collaboration with Polytech Tours from the University of Tours (France). This simulation package assists the designer in the sizing of PV (photovoltaic) installations. PVLab has a high level of flexibility, allowing its physical models and databases (e.g., meteorological data) to be modified according to the user’s needs. This is made possible through the use of expertise applied to all of the computing steps, and to the MATLAB development environment. The user’s ability to control the source code itself will allow much greater progress to be made in the field of renewable energy applications than with PVsyst, which is currently the commercial reference. All of these features come together to make PVLab the perfect tool for modernizing higher education, in particular with regard to students’ competencies. Since recent years, the higher education landscape has been undergoing considerable change as a result of technological innovations and new pedagogical approaches [1], [2], [3]. The Bologna Declaration and Lisbon Strategy in Europe are the clearest examples of international commitment to reform and modernization of university education [4], [5]. The degree and qualifications obtained, in terms of workload, level and learning outcomes are major pillars of the Bologna Process [6]. The competency-based management has been developed to increase the readability and comparability of European higher education degrees worldwide [7], [8]. This approach also supports the employability of higher education graduates [9]. Indeed, they are expected to be fully operational in an international context upon completion of their studies. About 100 Engineering Schools in France have already started the process at the moment. This movement should speed up with the Engineering Education Commission (CTI) guidelines. The Polytechnic Engineering School of the University of Tours (Polytech Tours, France) has just initiated the continuous skills development. The Electronics engineers to design and to have an in-depth understanding of electronic systems, has recently set up new pedagogical tools to achieve the education system modernization target. With regard to the education of photovoltaic (PV) applications in particular, recent researches have focused attention on students’ investment to give them the methods, tools, skills, and understanding since they could potentially be involved in the design, sizing, and installation of PV systems within an efficient industrial context [10], [11]. As the use of photovoltaics expands, with more and more commercial and residential users investing on solar energy systems around the globe, there is a growing demand for software that can be used for the design, simulation, data analysis, and troubleshooting of PV systems, from the preliminary assessment of energy efficiency and cost-effectiveness to the development of the project documentation. For many years, PVsyst has been accepted as a reference by architects, engineers, teachers and researchers, especially as a result of its easy-to-use, and accuracy of electrical energy production estimation thanks to its extensive PV- component, and meteorological databases [12]. However, using this kind of software package, it is not possible to modify the electrical, optical and thermal models, nor the internal databases (i.e., PV modules, inverters, and meteorological databases) [13]. A major question is whether existing commercial PV software, such as PVsyst, are sufficient to accurate forecast the efficiency of a PV plant taking into consideration all technical and environmental requirements.


terça-feira, 22 de novembro de 2016


A ICS Engenharia é um grupo de empresas de projetos e serviços com experiência de mais de 35 anos na área de Engenharia de Proteção contra Incêndio. Especialista e experiente no segmento de proteção contra incêndio soma casos de sucesso no atendimento aos seus clientes. Em constante crescimento, atualmente separou suas equipes em dois segmentos para atender com excelência a cada demanda:
 • Proteção contra incêndio
 • Controle de Acesso
 • Gerenciamento de obras
 • Manutenção dos equipamentos contra incêndio
 • Assistência Técnica
 • Automação industrial
 • Instalação de sistemas de proteção contra incêndio

WEBSITE :http://icsengenharia.com.br/

 CONTATO Av. Luiz José Sereno, 1.257 Jd. Ermida II – Jundiaí – SP – 
13212-210 55 11 4805-5501 qualidade@icsengenharia.com.br

TELEFONE (11) 4805-5501

segunda-feira, 21 de novembro de 2016

ANALYSIS OF AN INTEGRATED PFC INDUCTOR AND RESONANT TRANSFORMER BASED ON MAGNETIC MODELING - MEAS SARAN -Department of Electrical and Electronics Engineering Graduate School of Engineering Jeonju University Jeonju, Korea

ANALYSIS OF AN INTEGRATED PFC INDUCTOR AND RESONANT TRANSFORMER BASED ON MAGNETIC MODELING MEAS SARAN Advised by Prof. Kim, Eun Soo A thesis submitted to Jeonju University in partial fulfillment of the requirements for the degree of Master of Science Department of Electrical and Electronics Engineering Graduate School of Engineering Jeonju, University Feb 2013 ABSTRACT
This paper describes the design and analysis of an integrated transformer comprising of two different power cores- the PFC inductor and the LLC resonant transformer magnetic core. The equivalent magnetic circuit modeling approach is employed to analyze the variations in coupling coefficient and self-inductance in terms of air gaps under the operations of the respective power cores. Simulations and experimental studies were performed with the fabricated integrated transformer prototype and the results were discussed. In recent years, the demand for highly regulated and reliable power supplies with the desired smaller size, lighter weight and high efficiency in power electronics system has increased. The magnetic components are usually higher and heavier than other components on the circuit-boards. The answer for both miniaturization and material performance can be planar core technology. Therefore, the planar core was selected for 2-in-1 transformer design in this paper.

sexta-feira, 18 de novembro de 2016

Integrated Magnetic Transformer for ZVS Phase Shift Full Bridge Converter -By Xinlan Li-GYEONGSANG NATIONAL UNVERSITY Department of Electrical Engineering

Integrated Magnetic Transformer for ZVS Phase Shift Full Bridge Converter A Dissertation submitted to the Faculty of the Graduate School of the Gyeongsang National University By Xinlan Li In partial fulfillment of the requirements for the degree of Master of Engineering July, 2008

 Integrated Magnetic Transformer for ZVS Phase Shift Full Bridge Converter Xinlan Li Department of Electrical Engineering Graduate School Gyeongsang National University Supervised by Professor Hwi-Beom Shin
 Integrated magnetic (IM) has been widely used in power electronics system. The design of IM transformer is considered in a zero voltage switching (ZVS) phase shifted full bridge converter. The purpose of this design is to improve the performances, like power density, packaging, size and cost of IM transformer that can be applied to high frequency converter.
 In this dissertation a new IM transformer is proposed. The transformer is located on the center leg; the output inductor is located on the outer legs with air gaps. The design equations and equivalent magnetic circuit are presented. The analysis of each timing interval is included for ZVS. For reducing the core size, EE core is redesigned. The applications of these circuit are verified on a 1.2kW prototype converter through experimental results. The performance of the proposed IM transformer is compared with conventional IM transformer.
 The efficiency of proposed IM is similar to the one of conventional IM but the size of proposed IM is reduced up to 20%. Therefore, with the proposed IM transformer, the power density can be largely increased. I. Introduction The IM transformers begin to be used in the low output voltage and high current power electronics system [1]. With the IM technique, two or more magnetic components are integrated in one magnetic structure. The EE or EI core is commonly utilized. The magnetic parts in the converter may be reduced, so that the size and power density can be improved. In some case, overall efficiency may be increased and an EMI problem may be reduced. For a PSFB converter, several IM transformers are proposed [2]. The transformer winding is typically located on the two outer legs in series connection and the inductor is wound on the center leg. The AC flux of transformer and a half of the DC flux of inductor flows in outer legs but the inductor flux only flows in the center leg. The flux density in outer legs is much higher than one in center leg because the center leg has nearly two time cross-sectional area of the outer leg. This IM transformer has a high magnetizing inductance. Since the transformer coupling is low, EMI may be high. A new IM transformer is proposed for ZVS PSFB converter in this paper. The transformer winding is located on the center leg for close magnetic coupling and the inductor is wound on two outer legs in series connection. The proposed IM transformer is analyzed electrically and magnetically. An E-core is redesigned and implemented.
 The proposed IM transformer is experimentally compared with the conventional one through a 1.2kW prototype ZVS PSFB converter and the performance is discussed.

II. ZVS PSFB converter and IM transformer
 ZVS PSFB converter is shown in Fig. 1. The center-tapped transformer
and the output inductor are usually integrated in one EE or EI core. Fig. 2(a) shows the proposed IM transformer and the circuit connection in the output stage. The transformer and output inductor are located on the center leg and two outer legs, respectively. The conventional IM transformer given in [2] is shown in Fig. 2(b).

2.1 Operation Principle 
When the PSFB converter operates in ZVS, there are 8 operating modes during each cycle as shown in Fig. 3. The ZVS transition intervals are magnified in Fig. 3 and these intervals can be neglected when analyzing the magnetic circuit. Hence, 4 modes only are considered for analysis. The duty ratio D is limited below 0.5 because of the alternating current. The magnetic states within each core leg are modeled by using the capacitive modeling method [3] ~ [5]. For simplicity, all the devices are assumed to be ideal. The permeance of core is assumed to be infinite. The operation is explained as follows.

quinta-feira, 17 de novembro de 2016

Gerente General de KOLFF en Matelec 2016

Eduardo Cordero Homad, Gerente General de KOLFF, estuvo presente en la reciente feria Matelec 2016 la cual se realizó este año en la ciudad de Madrid. Algunas de las actividades programadas tuvieron relación directa con la suscripción de acuerdos corporativos de colaboración con proveedores europeos de clase mundial. En KOLFF nos preocupamos continuamente de entregar los mejores productos y servicios a nuestros clientes, y es en esta línea que año a año generamos alianzas en pro de generar valor agregado al mercado latinoamericano.

quarta-feira, 16 de novembro de 2016


A MODULAR ELECTRICAL POWER SYSTEM ARCHITECTURE FOR SMALL SPACECRAFT thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering in the College of Engineering at the University of Kentucky By Timothy Meng Lim Lexington, Kentucky 
Small satellites and CubeSats have established themselves within the aerospace community because of their low cost and high return on investment. Many CubeSats are developed in a short time frame and often leverage commercial off the shelf components for quick turnaround missions. With regard to the Electrical Power System, commercially available products typically use a centralized architecture. However, a centralized architecture is not reusable, since missions that require additional solar arrays or batteries would necessitate a redesign of the power system. With the range of CubeSat sizes and mission goals, it is obvious that a one-size-fits-all solution is not appropriate. This thesis details a reusable and scalable power system architecture applicable to a variety of missions. Reusability is achieved by using common building blocks or "modules," where the same modules can be used between missions. Scalability is achieved by not limiting the number of modules that can be connected together—more modules can be added as needed. In this system, solar arrays and battery units connect directly to a common bus, supplying an unregulated voltage to each subsystem. These subsystems then regulate the bus voltage to their individual needs. The power system also features direct energy transfer and solar-only operation.

Study on the Thermal Design of Nuclear Battery for Lunar Mission-한국형 달 탐사용 원자력전지의 열제어 구Jintae Hong1, , Kwang-Jae Son1, Jong-Bum Kim1

For a stable electric power supply in the space, nuclear batteries have been used as the main power source in a spacecraft owing to their long lifetime and high reliability. In accordance with the plan for lunar mission in Korea, nuclear batteries will supply electricity to the rover that needs to be developed. According to the information about the estimated payload, Korea Atomic Energy Research Institute started with the conceptual design based on the previous studies in USA and Russia. Because a nuclear battery converts the decay heat of the radioisotope into electricity, thermal design, radiation shield, and shock protection need to be considered. In this study, two types of nuclear batteries, radial type and axial type, were designed according to the alignment of the thermoelectric module. Heat transfer analyses were performed to compare their thermoelectric efficiency, and test mockups were fabricated to evaluate their performances.


The Study of Ripple Reduction of the PFC CCM Flyback Converter without Electrolytic Capacitor for LED Lightings using LC Resonant Filter-(Choon-Tack KIm․Young-Seok Kim)- LC 공진 필터를 이용한 전해 커패시터 없는 LED 구동용 PFC CCM 플라이백 컨버터의 출력 전류 리플 저감에 관한 연구

Abstract - The light-emitting diode (LED) has been used in a variety of industrial fields and for general 0lighting purposes on account of its high efficiency, low power consumption and long lifespan. The LED is driven by direct current; therefore, an AC/DC converter is typically required for its use. An electrolytic capacitor is generally used for stabilizing DC voltage during use of the AC/DC converter. However, this capacitor has a short lifespan, which makes it a limiting factor in LED lighting. Furthermore, LED lighting requires a dimmable control to enable energy savings and fulfil a growing consumer demand. In this paper, the dimmable single-stage power factor correction (PFC) continuous conduction mode (CCM) flyback converter that employs no electrolytic capacitor is presented. The LC resonant filter is alternatively applied to reduce the 120[Hz] ripple on the output. And the optimum value of the LC resonant filter parameters considering both efficient and performance is analysed. Simulation and experimental results verify the satisfactory operation of the converter.

Applications of PSCAD® / EMTDC Manitoba HVDC Research Centre Inc


Differential Protection for Arbitrary Three-Phase Power Transformers Zoran Gajić Doctoral Dissertation Department of Industrial Electrical Engineering and Automation Lund University- SWEDEN

Differential Protection for Arbitrary Three-Phase Power Transformers Zoran Gajić Doctoral Dissertation Department of Industrial Electrical Engineering and Automation Lund University- SWEDEN

This thesis describes how to provide standardized, current based, differential protection for any three-phase power transformer, including phase-shifting transformers with variable phase angle shift and transformers of all construction types and internal on-load tap-changer configurations. The use of standard transformer differential protection for such applications is considered impossible in the protective relaying standards and practices currently applied. The first part of the thesis provides the background for different types of power transformers and the differential protection schemes currently applied. After that a complete mathematical proof for the new, universal transformer differential protection principle, based on theory of symmetrical components, is derived. It is demonstrated that it is possible to make numerical differential protection relays which can properly calculate differential currents for any power transformer, regardless of whether it is of fixed or variable phase angle shift construction and whether current magnitude variations are caused by on-load tapchanger( s). It is shown how to correctly calculate differential currents by simultaneously providing on-line compensation for current magnitude variations, on-line compensation for arbitrary phase angle shift variations and settable zero-sequence current reduction on any power transformer side. By using this method differential protection for arbitrary power transformers will be ideally balanced for all symmetrical and nonsymmetrical through-load conditions and external faults. The method is independent of individual transformer winding connection details (i.e. star, delta or zigzag), but dependent on having the correct information about actual on-load tap-changer(s) position if they are built-in within the protected power transformer. The implementation and practical use of this new universal principle is quite simple, as all necessary transformer data is commonly available on the protected power transformer rating plate. Practical application of the universal method for the differential protection of standard transformers, special transformers and phase shifting transformer is presented. Detailed testing of this new universal differential protection method is given and it is based on actual field recordings captured by numerical relays in existing phase-shifting transformer installations and on simulations from the Real Time Digital Simulator for a practical dual-core, symmetrical phaseshifting transformer. The implementation of the universal transformer differential method for analogue and numerical transformer differential relays is also described.

segunda-feira, 14 de novembro de 2016

Triplen Harmonics Mitigation 3 Phase Four-Wire Electrical Distribution System Using Wye- Zig-Zag Transformers Rosli Omar, Azhar Ahmad and Marizan Sulaiman Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka

This paper studies an application of wye- zigzag transformes for reducing harmonics in the neutral conductors of a three phase 415/240V distribution system. Triplen harmonic currents add up in the neutral conductor of the distribution system feeding the non linear loads such as personal computers and electronic office machines with switch mode power supplies. The zigzag transformer is installed between the distribution panel and the high harmonics producing loads. This research makes use of a star-zigzag grounded transformer.


Winding Method of Transformer for Zero-Sequence and Negative-Sequence Harmonic Elimination Kim, Tae-Hoon; Park, Jun-Yeal - 영상분 및 역상분 고조파 제거를 위한 변압기 결선방식

영상분 및 역상분 고조파 제거를 위한 변압기 결선방식 Winding Method of Transformer for Zero-Sequence and Negative-Sequence Harmonic Elimination 김 태 훈*․박 준 열† (Tae-Hoon Kim․Jun-Yeal Park) 

As the various kinds of load who generate higher harmonics increases according as the power electronics technology develops, harmonic treatment standard is proposed by IEEE and IEC. Because establishment of harmonic reduction device is required for existent installment to satisfy harmonic treatment standard, the problem of investment charge and installation space increasing may be occurred. In order to solve these problems, a novel transformer connection method using principles of PCT and ZED is suggested.

ISSN 1975-8359(Print) / ISSN 2287-4364(Online)
The Transactions of the Korean Institute of Electrical Engineers Vol. 63, No. 7, pp. 896~902, 2014


sábado, 12 de novembro de 2016

Счетчики и регистры сдвига - Counters and shift registers-Anatoly Leonidovich Larin

О лекции Счетчик. Вычитающий счетчик и реверсивный счетчик. Временные задержки в счетчиках с последовательным переносом. Счетчик по произвольному модулю. Счетчик по произвольному модулю. Лекторы Ларин Анатолий Леонидович кандидат технических наук, доцент кафедры радиотехники МФТИ

Counters and shift registers
Anatoly Leonidovich Larin
Ph.D., Associate Professor, Department of Radio Engineering MIPT
Московский физико-технический институт

quinta-feira, 10 de novembro de 2016


This thesis proposes hardware circuits and control algorithm of grid-connected photovoltaic (PV) inverters having high efficiency. PV inverter can be classified into singlephase and three-phase inverter according to power capacity. A micro-inverter system is proposed for the single-phase inverter. This system is composed of step-up dc-dc converter that uses an active-clamp circuit with a series-resonant voltage doubler and a high efficiency inverter with single-switch-modulation. During the step-up dc-dc stage, the active-clamp circuit provides zero-voltage switching turn-on, recycles the energy stored in the leakage inductance of the transformer, and limits switch voltage stress. A series-resonant voltage doubler is used on the transformer secondary side to remove the reverse-recovery problem of the rectifier diodes. During the inverter stage, to improve efficiency and reliability in the proposed inverter, only single switch is modulated at switching frequency without shoot-through problem. This whole process minimizes power losses and eliminates a mismatch of a capacity between the PV panel and PV inverter, so the proposed micro-inverter is suitable for use in a single-phase grid connected PV inverter. A prototype design and experimental results are given to verify the proposed system. A novel space-vector modulation (SVM) for a three-phase PV inverter with simple software implementation is proposed. The conventional SVM algorithm for the three-phase PV inverter requires complex computations, such as square root and arctangent, and a sector selection algorithm. The proposed SVM algorithm can determine directly on-state times of switches without complex computations and complex sector selection algorithm. Experimental results show high performance of the proposed algorithm for the three-phase PV inverter.