PALESTRA NOBREAKS KOLFF PERNAMBUCO BRASIL

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

 Abstract
 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.

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