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.
LINK
http://kolff-e.com/2016/11/04/gerente-general-de-kolff-en-matelec-2016/

A MODULAR ELECTRICAL POWER SYSTEM ARCHITECTURE FOR SMALL SPACECRAFT Timothy M. Lim University of Kentucky,

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 
 ABSTRACT OF THESIS A MODULAR ELECTRICAL POWER SYSTEM ARCHITECTURE FOR SMALL SPACECRAFT 
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.
LINK ORIGINAL WEB
http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1096&context=ece_etds

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

ABSTRACT
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.

LINK
http://ocean.kisti.re.kr/downfile/volume/kspe/JMGHBV/2016/v33n4/JMGHBV_2016_v33n4_271.pdf

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.
 LINK ORIGINAL EN LA WEB
http://ocean.kisti.re.kr/downfile/volume/kiee/DHJGII/2016/v65n4/DHJGII_2016_v65n4_601.pdf

Applications of PSCAD® / EMTDC Manitoba HVDC Research Centre Inc

LINK ORIGINAL EN LA WEB
http://www.mediafire.com/file/n8cc6sk5gr6ki4y/Application_Guide_2007.pdf

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

 Abstract
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.
LINK ORIGINAL EN LA WEB
http://www.iea.lth.se/publications/Theses/LTH-IEA-1055.pdf

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.

 LINK ORIGINAL
http://jeteas.scholarlinkresearch.com/articles/TRIPLEN%20HARMONIC%20MITIGATION.pdf

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) 

 Abstract
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
http://dx.doi.org/10.5370/KIEE.2014.63.7.896

LINK ORIGINAL FULL PAPER
http://ocean.kisti.re.kr/downfile/volume/kiee/DHJGII/2014/v63n7/DHJGII_2014_v63n7_896.pdf

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

Power Conversion Technology for Grid-connected PV Inverter-WOO-JUN CHA -DOCTORAL THESIS-DEPARTMENT OF ELECTRICAL ENGINEERING POHANG UNIVERSITY OF SCIENCE AND TECHNOLOGY-SOUTH KOREA

ABSTRACT
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.