Research Article Controlling Transformer Magnetizing Offset Current in Isolated Phase-Shift Full-Bridge Converters Using a Luenberger Observer -Angelika Neumann, Sönke Meynen, Ahmad Rahmoun, Daniel Ziegler, Thomas Kirchartz---Karlsruhe University of Applied Sciences, Karlsruhe, Germany

Controlling Transformer Magnetizing Offset Current in Isolated Phase-Shift Full-Bridge Converters Using a Luenberger Observer Angelika Neumann, Sönke Meynen, Ahmad Rahmoun, Daniel Ziegler, Thomas Kirchartz 

Abstract This paper proposes a flexible digital control scheme for isolated phase-shift full-bridge (PSFB) converters. The required transformer suffers from inevitable imbalance of magnetic flux resulting in an increased magnetizing DC-offset current that threatens system reliability due to saturation effects. The paper addresses two major issues of the occurrence of a magnetizing DC-offset current. First, caused by the change of duty cycle due to output power regulation and second caused by initial manufacturer tolerances of devices. In contrast to common methods the novel control scheme uses a Luenberger observer to estimate the magnetizing current requiring only simple measurement of transformer voltages without additional and lossy auxiliary networks. The observer model, in combination with a PI-controller, directly interventions the duty cycle and removes any DC-offset current resulting from both issues. A detailed deviation of the state-space model of the transformer and a subsequently design of the observer are presented. Simulation and experimental results on a PSFB prototype verify the principal functionality of the proposed control scheme to prevent transformer saturation. 

 International Transactions on Electrical Energy Systems Volume 2022, Article ID 9243429, 15 pages https://doi.org/10.1155/2022/9243429 

ORIGINAL LINK: https://onlinelibrary.wiley.com/doi/10.1155/2022/9243429 

Single-Stage Multi-Port Solid-State Transformer (SST) Based Medium-Voltage DC (MVDC) Interconnection System and Coordinated Control Strategies - Di Zhu, Chuang Liu, Jingyue Wang, Zhongchen Pei*, Chao Liu, Heyang Sun, Yu Jiang Northeast Electric Power UniversityDalian University of Technology

Single-Stage Multi-Port Solid-State Transformer (SST) Based Medium-Voltage DC (MVDC) Interconnection System and Coordinated Control Strategies Di Zhu, Student Member, IEEE, Chuang Liu, Member, IEEE, Jingyue Wang, Zhongchen Pei, Chao Liu, Member, IEEE, Heyang Sun, Yu Jiang 

Northeast Electric Power University

Dalian University of Technology

Abstract—Decentralized integration of distributed generation (DG) units and loads are increasing in the modern distribution grid. Maintaining the power flow and power quality within their accepted limits is a challenging task. This paper proposes a medium-voltage DC (MVDC) interconnection system based on the single-stage multi-port solid-state transformers (SST). First, the single-stage multi-port SST's coordinated control strategies and energy management method are discussed, aiming at the flexible power flow control between the utility grid, MVDC grid and the low-voltage AC/DC microgrid. Secondly, the MVDC controller parameters and SST passive components are optimized based on the impedance interaction characteristics between the two SSTs' MVDC ports, thereby enhancing the stability margin of the interconnected system. Then the operation modes of the interconnected system are defined. Finally, the effectiveness of the proposed operation modes and control strategy is verified through a 1-MW simulation platform, while a 1-kW scaled-down experimental prototype is built to further validate the single-stage multi-port SST and the MVDC interconnected system.

ORIGINAL LINK: https://orbit.dtu.dk/en/publications/single-stage-multi-port-solid-state-transformer-sst-based-medium-/ 

Bidirectional Grid-Forming Converter with Modified Voltage Control for Enhanced Power Dynamics Dos Santos Serra, Amiron Wolff; Nascimento, Khristian Augusto Freitas; De Matos, José Gomes; De Souza Ribeiro, Luiz Antonio; Savaghebi, Mehdi; Oliveira, Hércules Araújo Department of Engineering Technology and Didactics Federal University of Maranhão

Abstract— This paper proposes a control strategy for a bidirectional grid-forming converter, operating as a virtual synchronous generator, based on an improved voltage controller to enhance the dynamics of the active and reactive power loops. The theoretical analysis and real-time simulation results demonstrate the enhanced disturbance rejection of the proposed strategy, which is based on disturbance input decoupling. Furthermore, virtual impedance is used to limit the current injected by the converter during grid transitory situations.

ORIGINAL LINK: https://orbit.dtu.dk/en/publications/bidirectional-grid-forming-converter-with-modified-voltage-contro/ 

Green & Black-starting HVDC-connected Offshore Wind Power Plants: Grid forming control, Energization transients and Islanding capabilities - Anubhav Jain

 

Summary

 Green energy transition is the most urgent need of the hour to curb the rising impact of global warming. The carbon-neutral energy system of the future will have electricity as its backbone, which requires a domination of renewable sources and long distance interconnections. However, such a transformation brings forth a massive penetration of power electronic converters to allow for flexibility in operation that is essential for efficient and cost-effective grid usage. This paradigm shift will make future power grids very different from the current system resulting in a highly dynamic environment that poses a risk to power system stability. Coupled with the declining strength of the network, it has the potential to increase the impact of severe network disturbances and give rise to challenges for the containment of voltages and frequency excursions, ultimately triggering wide-area blackouts. Since conventional synchronous generation is being phased out, the responsibility to maintain power system stability and provide network restoration services must be taken up by alternate sources of generation. Being one of the fastest growing renewable energy sources in the world, offshore wind is deemed a prime candidate.

ORIGINAL LINK: https://orbit.dtu.dk/en/publications/green-amp-black-starting-hvdc-connected-offshore-wind-power-plant/ 

A Multi-Loop Control for Grid-Forming Converters with Enhanced Dynamics Amiron Wolff Dos Santos Serra, Luiz Antonio De Souza Ribeiro, Mehdi Savaghebi-Institute of Electrical Energy Federal University of Maranhão São Luís – MA, Brazil-Department of Engineering Technology Technical University of Denmark (DTU)-

 

A Multi-Loop Control for Grid-Forming Converters with Enhanced Dynamics Amiron Wolff Dos Santos Serra, Luiz Antonio De Souza Ribeiro, Mehdi Savaghebi Department of Engineering Technology and Didactics

 2024 Energy Conversion Congress & Expo Europe - Darmstadt, Germany Duration: 2 Sept 2024 → 6 Sept 2024

 Abstract This paper proposes a control strategy for grid-forming converters based on a cascade control scheme with current and voltage controllers and an outer loop to control the injected active and reactive power. The analysis demonstrates the increased disturbance rejection capability of the current controller, and the improved loop gain in the low-frequency region of the voltage controller from the concept of disturbance input decoupling. Simulation results prove the effectiveness of the proposed strategy. 

ORIGINAL LINK: https://orbit.dtu.dk/en/publications/a-multi-loop-control-for-grid-forming-converters-with-enhanced-dy/ 

Advances in High Frequency Inductor Design for Power Converter Bima Nugraha Sanusi Ph.D.Thesis Technical University of Denmark.

 

Advances in High Frequency Inductor Design for Power Converter Bima Nugraha Sanusi Ph.D.Thesis Technical University of Denmark. 

 Abstract  

The Power Sources Manufacturers Association roadmap identifies high-efficiency and high-power-density end-use of electricity as one of the key challenges to increase the economic growth rate with a minimal environmental impact. The challenge in realizing smaller, faster, and in turn greener power supplies is the integration of magnetic materials that can operate efficiently at high frequency. The most successful work will involve magnetic material development, optimization of magnetic component designs, and consideration of fabrication constraints. This project primarily aims for a high-efficiency and high-power-density power management (DC/DC converter) from the USB-C port to the battery within the next generation of fast-charging smartphones or other portable electronic devices. This thesis hypothesizes that employing superparamagnetic nanoparticles material, which has high permeability and negligible hysteresis loss, in high-frequency inductor design can enable high-efficiency and high-power-density converter. The focus of this thesis will be on the magnetic material characterization and the inductor design. The first step is to establish a baseline prototype with state-of-the-art magnetic material. Multi-phase Zero Voltage Switching (ZVS) Buck converter is the selected topology to achieve high power density. A novel utilization of 4-leg magnetic core is proposed as the integrated inductor. From the constructed inductor model and semiconductor losses calculation, the design trade-off is analyzed. The optimal switching frequency is found to be around 2 MHz in this case, which is when the core material performance factor peaks. As proof of concept, a highly compact prototype, featuring stacked PCB solution is built. The input voltage ranges from 6 V to 12 V and the converter can deliver up to 10 A at 4 V output. The converter reaches a nominal efficiency of 88% and has a power density of 301 W/in3. The second step is to build a platform for magnetic core characterization, in particular the core loss. Mutual inductance compensation method is employed in the measurement circuit to reduce sensitivity to phase errors. An addition to the circuit is proposed in this work to make easier DC bias generation. This platform is used to study the core losses behavior at high frequency with superimposed DC bias in ferrite. The tested MnZn ferrite has a nominal relative permeability of 1500 and 800, which was tested at frequency from 500 kHz to 3 MHz. The measurement results are explained thoroughly with three controlling parameters: excitation frequency, AC flux density amplitude, and DC bias. Furthermore, an improved Steinmetz Premagnetization Graph and Artificial Neural Network are used to create core loss prediction model. The measurement data and built model can be accessed online for use by another magnetics designer. The third step is to analyze the switching transition in multi-phase half-bridge circuit with coupled inductors. It was found that the coupled inductors can achieve or maintain ZVS in the cases where non-coupled inductors cannot. Moreover, the coupled inductors can reduce the required deadtime to achieve ZVS. This benefit comes from the increased amplitude and frequency of resonant voltage in the presence of coupled inductors. The impact is quantified, analyzed, and verified in this thesis. 

ORIGINAL LINK: https://orbit.dtu.dk/en/publications/advances-in-high-frequency-inductor-design-for-power-converter/ 

Estudo, análise e projeto de sistemas magnéticos aplicados a conversores estáticos-Pedro Cerutti Bolsi-UNIVERSIDADE FEDERAL DE SANTA MARIA CENTRO DE TECNOLOGIA PROGRAMA DE POS-GRADUAQAO ЕМ ENGENHARIA ELETRICA-BRASIL

 

Estudo, análise e projeto de sistemas magnéticos aplicados a conversores estático- Pedro Cerutti Bolsi

UNIVERSIDADE FEDERAL DE SANTA MARIA CENTRO DE TECNOLOGIA PROGRAMA DE POS-GRADUACÂO ЕМ ENGENHARIA ELÉTRICA

 Dissertação apresentada ao Curso de Mestrado do Programa de Pós-graduação em Engenharia Elétrica ,da universidade federal de Santa Maria (UFSM-RS) como requisito parcial para obtenção do grau de Mestre em Engenharia Elétrica. 

RESUMO 

Uma vez que o projeto volumétrico de transformadores e indutores está diretamente ligado às perdas, a predição correta destas é fundamental para a sua otimização. Sob esta ótica, este trabalho apresenta técnicas de modelagem de perdas no cobre e no núcleo de dispositivos magnéticos, através da abordagem de dois assuntos pertinentes ao seu projeto. O primeiro trata-se de um estudo da modelagem das perdas no núcleo, fazendo uso de modelos empíricos baseados na equação de Steinmetz. Uma análise comparativa entre os principais modelos analíticos é feita, bem como um levantamento experimental, a fim de verificar a exatidão dos modelos e a influência do ponto de operação sobre as perdas, incluindo a premagnetização. Para o material avaliado, de tecnologia High Flux, é demonstrado que, na faixa analisada, a premagnetização não possui influência sobre as perdas. A modelagem recomendada pelo fabricante, baseada na equação de Steinmetz, é válida para a razão cíclica de 0,5, e a modelagem da IGSE (Improved Generalized Steinmetz Equation), que por sua vez prevê variações de razão cíclica, possui boa acurácia. O segundo tema abordado é o reprojeto do transformador de uma UPS Line Interactive visando aumentar o seu rendimento global. Através da modelagem das perdas do transformador, a caracterização, quantificação e relativização das perdas permite a identificação dos pontos de melhoria para o reprojeto do transformador, e com a reprodução da LI-UPS em simulação, o rendimento com novos transformadores é estimado pelos modelos de perdas co-validados experimentalmente. Fazendo-se pequenas alterações no projeto do transformador, os protótipos analisados elevaram o rendimento global do equipamento em até 1,11% no ponto mais alto da curva original, e em até 2,60% nas potências mais elevadas.

Ver Dissertação Completa :https://repositorio.ufsm.br/handle/1/22435

Metodologia de projeto otimizado de filtros de entrada e saída de fontes ininterruptas de energia: volume, perdas e tempo de vida-Pedro Cerutti Bolsi-UNIVERSIDADE FEDERAL DE SANTA MARIA CENTRO DE TECNOLOGIA PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA ELÉTRICA-BRASIL

 

Pedro Cerutti Bolsi

 METODOLOGIA DE PROJETO OTIMIZADO DE FILTROS DE ENTRADA E SAÍDA DE FONTES ININTERRUPTAS DE ENERGIA: VOLUME, PERDAS E TEMPO DE VIDA 

Tese apresentada ao Curso de Doutorado do Programa de Pós-Graduação em Engenharia Elétrica, Área de Concentração em Processamento de Energia Elétrica, da Universidade Federal de Santa Maria (UFSM-RS), como requisito parcial para obtenção do grau de Doutor em Engenharia Elétrica

 

Orientador: Prof. Dr. José Renes Pinheiro Coorientador: Prof. Dr. João Manoel Lenz Santa Maria, RS 2024

 RESUMO

 METODOLOGIA DE PROJETO OTIMIZADO DE FILTROS DE ENTRADA E SAÍDA DE FONTES ININTERRUPTAS DE ENERGIA: VOLUME, PERDAS E TEMPO DE VIDA AUTOR: PEDRO CERUTTI BOLSI 

ORIENTADOR: JOSÉ RENES PINHEIRO 

COORIENTADOR: JOÃO MANOEL LENZ

 Neste trabalho são desenvolvidas metodologias de projeto de filtros LCL e LC, considerando o seu impacto em todo o sistema. A metodologia proposta busca, através de uma varredura paramétrica, a obtenção dos pontos ótimos de projeto para o rendimento, o volume, e o tempo de vida dos capacitores do circuito. Para este fim, a metodologia possui dois estágios. O primeiro consiste na realização do projeto paramétrico dos filtros, no qual é feita uma varredura de entradas de projeto, delimitada pelas restrições normativas e de operação do conversor. Utilizando a estratégia proposta, diferentes combinações de valores de L-C-L e L-C que atendem às restrições normativas são levantadas. O segundo estágio consiste na realização do projeto dos componentes dos filtros, determinando a sua construção a partir de diferentes tecnologias. Uma vez que a varredura paramétrica das entradas de projeto dos filtros influencia o restante do sistema através de alterações no conteúdo harmônico (ondulação de corrente), são determinadas as perdas e o tempo de vida dos capacitores do barramento CC, as perdas nos semicondutores dos conversores em análise, e o projeto dos dissipadores de calor. Por fim, resultados são analisados para os projetos de filtros que resultem no menor volume do sistema, melhor rendimento, e/ou maior tempo de vida dos capacitores. São apresentados os procedimentos de projeto de cada parte do sistema de potência, bem como os modelos utilizados no projeto dos indutores, e nas estimativas de perdas, temperatura e tempo de vida. Com a metodologia proposta, é desenvolvido um estudo de caso de uma fonte ininterrupta de energia trifásica a quatro fios de 10 kVA, analisando a possibilidade de construção dos indutores com três tecnologias diferentes de materiais magnéticos (aço-silício de grão não-orientado, ferrite IP6, Kool Mμ), de diferentes geometrias (EE e toroidal), e considerando duas tecnologias de capacitores para o sistema. Os resultados demonstram como, utilizando a metodologia de projeto proposta, as características de cada tecnologia influenciam no resultado final, possibilitando a determinação do melhor ponto de projeto para os filtros LCL e LC..

VER TESE COMPLETA; https://repositorio.ufsm.br/handle/1/31906 

Design of Uninterruptible Power Supply Inverters for Different Modulation Techniques Using Pareto Front for Cost and Efficiency Optimization Edemar O. Prado * , Pedro C. Bolsi , Hamiltom C. Sartori and José R. Pinheiro

Design of Uninterruptible Power Supply Inverters for Different Modulation Techniques Using Pareto Front for Cost and Efficiency Optimization Edemar O. Prado * , Pedro C. Bolsi , Hamiltom C. Sartori and José R. Pinheiro Energy Efficiency Lab, LABEFEA, Federal University of Bahia, Salvador 40170-110, BA, Brazil Power Electronics and Control Research Group, GEPOC, Federal University of Santa Maria, Santa Maria 97105-900, RS, Brazil

 Abstract This work presents a design for uninterruptible power supply inverters using Pareto front optimization for improved cost and efficiency. Three PWM modulation techniques applied to the full-bridge inverter are analyzed. As a result, the best MOSFET design solution in terms of the cost and efficiency of the inverter is evaluated based on a database with 47 power MOSFETs. Using the Pareto front, the optimal and sub-optimal solutions are compared, considering the three modulation techniques and the characteristics of MOSFETs manufactured for different voltage levels. Thermal and electrical measurements are used to validate the models. 

LINK:https://www.mdpi.com/1996-1073/16/3/1314

Simple Method to Estimate Battery Lifetime and Upkeep of Lead-Acid and Lithium-Ion Batteries- AUTORES :Pedro C. Bolsi , Edemar O. Prado , Romario J. Nazaré , Hamiltom C. Sartori , José R. Pinheiro-Universidade Federal de Santa Maria, Santa Maria - RS, Brasil -Universidade Federal da Bahia, Salvador - BA, Brasil

 

Eletrônica de Potência Special Issue Open Journal of Power Electronics Received July 03, 2024; accepted November 24, 2024; Date of publication December 15, 2024. The review of this paper was arranged by Associate Editor Fabio Andrade and Editor-in-Chief Heverton A. Pereira 

 Simple Method to Estimate Battery Lifetime and Upkeep of Lead-Acid and Lithium-Ion Batteries- AUTORES :Pedro C. Bolsi , Edemar O. Prado , Romario J. Nazaré , Hamiltom C. Sartori , José R. Pinheiro-Universidade Federal de Santa Maria, Santa Maria - RS, Brasil -Universidade Federal da Bahia, Salvador - BA, Brasil 

 ABSTRACT This work provides an event-oriented method to model and predict the lifetime of leadacid and lithium-iron phosphate batteries. An ampere-hour integration method is proposed to be used in conjunction with the event-oriented method to achieve higher accuracy. The methods are applied to lead acid and lithium-iron phosphate batteries on a commercial 1 kW single-office/home-office uninterruptible power supply (UPS). Additional circuits for measurements, or microprocessors are avoided to not increase the UPS cost, reducing its market competitiveness. The usefulness of the proposed approach is demonstrated by an upkeep analysis based on the cost of the battery and the service time for each battery technology. 

ORIGINAL LINK:  https://journal.sobraep.org.br/index.php/rep/article/view/981

 LINK1:  https://journal.sobraep.org.br/index.php/rep/article/view/981/881

LINK2 :https://www.mediafire.com/file/l1ssoq6c2wpuseh/REP_2024_0038.pdf/file

Controle de Topologias para UPS line-interactive sem transformador-Alan R. Pinto ,Edemar Prado ,Pedro Bolsi , Talis Piovesan ,Luan Mendonca ,Filipe Bahia, Marcio Fontana ,Hamiltom Sartori UFSM Santa Maria, Brazil , Jose R. Pinheiro Univali/UFSM/UFBA

 

Controle de Topologias para UPS line-interactive sem transformador 

Alan R. Pinto ,Edemar Prado ,Pedro Bolsi , Talis Piovesan ,Luan Mendonca ,Filipe Bahia, Marcio Fontana ,Hamiltom Sartori UFSM Santa Maria, Brazil , Jose R. Pinheiro Univali/UFSM/UFBA

 Abstract—Este artigo apresenta uma abordagem de controle clássico aplicada a três tipologias de Fontes de Alimentação Ininterrupta (UPS) monofásicas, interativas em linha, sem trans- formador. O objetivo principal ´e demonstrar que soluções de controle menos complexas e de baixo custo podem ser eficazes, além de oferecerem facilidade de manutenção, em contraste com abordagens de controle mais robustas e caras. As topologias analisadas — ponte completa, ponte completa com braço compar- tilhado e meia ponte — são avaliadas quanto ao seu desempenho nos modos de operação conectado `a rede e de backup. Os resultados mostram que, mesmo com controle clássico, essas topologias são capazes de regular a tensão de saída e compensar a corrente harmônica, mantendo a qualidade da energia fornecida a cargas não lineares.

VER ARTIGO COMPLETO NO SEGUINTE ENLACE:  http://repositorio.ufsm.br/handle/1/37065

AI Load Dynamics–A Power Electronics Perspective Yuzhuo Li, and Yunwei Li Department of Electrical and Computer Engineering University of Alberta, Edmonton, Canada

 

 

 

AI Load Dynamics–A Power Electronics Perspective Yuzhuo Li1, and Yunwei Li1 1Department of Electrical and Computer Engineering University of Alberta, Edmonton, Canada 

 Abstract—As AI-driven computing infrastructures rapidly scale, discussions around data center design often emphasize energy consumption, water and electricity usage, workload scheduling, and thermal management. However, these perspectives often overlook the critical interplay between AI-specific load transients and power electronics. This paper addresses that gap by examining how largescale AI workloads impose unique demands on power conversion chains and, in turn, how the power electronics themselves shape the dynamic behavior of AI-based infrastructure. We illustrate the fundamental constraints imposed by multi-stage power conversion architectures and highlight the key role of final-stage modules in defining realistic power slew rates for GPU clusters. Our analysis shows that traditional designs, optimized for slower-varying or CPU-centric workloads, may not adequately accommodate the rapid load ramps and drops characteristic of AI accelerators. To bridge this gap, we present insights into advanced converter topologies, hierarchical control methods, and energy buffering techniques that collectively enable robust and efficient power delivery. By emphasizing the bidirectional influence between AI workloads and power electronics, we hope this work can set a good starting point and offer practical design considerations to ensure future exascale-capable data centers can meet the stringent performance, reliability, and scalability requirements of nextgeneration AI deployments.

ORIGINAL LINK:  https://arxiv.org/pdf/2502.01647v2

Alguns aspectos da investigação sobre a viabilidade da construção de uma usina nuclear na Lua-V.V. Belov, S.A. Sazonova-Некоторые аспекты исследования возможности строительства АЭС на Луне-Vyacheslav V. Belov , Svetlana A. Sazonova

Alguns aspectos da investigação sobre a viabilidade da construção de uma usina nuclear na Lua V.V. Belov, S.A. Sazonova ✉ Universidade Estadual de Engenharia Civil de Moscou (NRU MGSU), Moscou, Federação Russa

 Resumo. A exploração espacial é uma prioridade para o desenvolvimento de qualquer grande nação, uma vez que enfrentar os desafios tecnológicos associados impulsiona o progresso futuro. Claramente, tal exploração é impossível sem o estabelecimento de uma fonte de energia confiável diretamente no espaço. Este estudo concentra-se em uma análise conceitual da viabilidade de construir uma usina nuclear (UN) estacionária na Lua. Foi realizada uma revisão de informações de fontes abertas para identificar sistemas de energia nuclear existentes ou em desenvolvimento, capazes de operar sob "condições lunares" e, ao mesmo tempo, atender aos requisitos de segurança e descarte. Além disso, foram selecionados modelos específicos de veículos lançadores das classes pesada e superpesada (tanto existentes quanto conceituais) capazes de transportar cargas úteis de 10 toneladas ou mais para a Lua. Com base na análise de dados de sistemas de reatores e informações sobre as condições de operação e construção na Lua, desenvolveu-se um projeto conceitual de uma estrutura de contenção "reutilizável" para uma UN lunar estacionária; essa estrutura serve para fornecer proteção contra a queda de corpos celestes, flutuações de radiação e radiação solar (calor solar). São apresentados os conceitos fundamentais relativos às etapas de construção, operação e descomissionamento, destacando-se as questões associadas à criação, ao desenvolvimento e ao descarte de instalações nucleares e estruturas de contenção de UNs estacionárias em um ambiente sem atmosfera (como em um corpo celeste) — questões que existem atualmente e requerem pesquisa ao longo da próxima década.

O TEXTO ORIGINAL ESTA EM IDIOMA RUSSO FOI TRADUZIDO AO PORTUGUÊS NESTE LINK 

DOWNLOAD LINK : https://www.mediafire.com/file/pasvvn1xjgc3tyt/Alguns+aspectos+da+investigação+sobre+a+viabilidade+da+construção+de+uma+usina+nuclear+na+Lua.pdf/file

High voltage semiconductor voltage pulse generator for capillary discharge formation in soft X- ray radiation source Andrey A. Samokhvalova,b , Kirill A. Sergushichevb , Stepan I. Eliseevb,c , Artyom A. Smirnovb ✉, Maria V. Timshinab , Timur P. Bronzovb a Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, Saint-Petersburg, Russian Federation

 

High"voltage semiconductor voltage pulse generator for capillary discharge formation in soft X"ray radiation source Andrey A. Samokhvalova,b , Kirill A. Sergushichevb , Stepan I. Eliseevb,c , Artyom A. Smirnovb ✉, Maria V. Timshinab , Timur P. Bronzovb 

 Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, Saint-Petersburg, Russian Federation b «Laboratory V.A. Burtseva» LLC, Saint-Petersburg, Russian Federation c St. Petersburg State University, Saint-Petersburg, Russian Federation

 Abstract. The results of the development of a high-voltage semiconductor voltage generator (based on IGBT transistors) with a pulse transformer and the results of experiments on generating a capillary discharge using it on a compact gas-discharge source capable of generating pulses of soft X-ray radiation (SXR) in the area of the socalled «water window» — with wavelength in the range of 2.4...4.4 nm. Methods for designing a high-voltage pulse voltage pulse generator are described: theoretical calculations and results of modeling the electrical circuit diagram in the LTSpice software package, the developed design of a pulse transformer based on N87 ring ferrites and the generator itself is described, the results of its operation as part of a compact gas-discharge radiation source are presented and analyzed. The prospects of using such a high-voltage generator (with semiconductor transistor switches) with a pulse transformer as part of a soft X-ray radiation source are shown due to its technical and operational features: the developed generator is capable of operating from an alternating current network of 380 V/50 Hz in a frequency-burst mode (with a repetition rate of the generated voltage pulses up to 600 Hz) and charges the capillary capacitance of the SXR source to a voltage of more than 20 kV in a time of about 4 μs, has small dimensions, does not create pulsed high-frequency interference and false alarms, and also has stable output (amplitude-temporary) parameters.

ORIGINAL RUSSIAN LANGUAGE:https://journals.rudn.ru/engineering-researches/article/download/37372/22992

 TRANSLATED FROM RUSSIAN TO ENGLISH :https://www.mediafire.com/file/704heq0czec2pcj/Highvoltage+semiconductor+voltage+pulse+generator-ENGLISH.pdf/file

INSTRUMENTS AND METHODS OF INVESTIGATION PACS - Physical principles of filtration and the design of terahertz radiation filters A.K. Kaveev, G.I. Kropotov-Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences

 

Physical principles of filtration and the design of terahertz radiation filters 

 Contents
1. Introduction 169
2. Basic physical principles of THz radiation filtering 170
2.1 Filtration of THz radiation in absorbing layers; 2.2 Filtering of THz radiation using metamaterials
3. THz filters based on absorbing materials 175
3.1 Spectral studies of materials for fabricating THz cutoff filters; 3.2 Cutoff filters
4. THz filters based on metamaterials 177
4.1 Geometries and equivalent circuits of FSSs used as real THz filters; 4.2 THz notch filters; 4.3 Filters based on
resonant switching by photoexcitation; 4.4 THz high-pass filters; 4.5 Technologies for manufacturing metamaterials
for THz filters and other FSS-based passive optical elements
5. THz polarization filters 183
6. THz plasmonic Filters 184
7. Exotic THz filter 184
8. Conclusions 186
References

 Abstract. Present review examines the basic physical principles of operation of terahertz radiation filters. The main types of filters are presented, namely, based on absorbing/scattering materials, metamaterials (frequency-selective surfaces), interference, polar- ization, and some exotic types. The basic principles of calculating the filters transmission based on matrix methods are described, as well as based on solving Maxwell's equations. The areas of application of THz filters are listed. 

FULL PAPER : LINK1 :https://ufn.ru/ufn2026/ufn2026_2/ufn262e.pdf

LINK2 : https://www.mediafire.com/file/nj0pxmeqw6wlyx9/Physical+principles+of+filtration+and+the+design+of+terahertz+radiation.pdf/file 

TESTE PLACA CARREGADOR DE BATERIAS UPS ONLINE 2KVA -6 BATERIAS DE 12VDC

 

THE IGBT TEST SETUP DESIGN Master Thesis By Kun Liu Abdirahman Hirsi-Division of Electric Power Engineering Department of Energy and Environment CHALMERS UNIVERSITY OF TECHNOLOGY

 

THE IGBT TEST SETUP DESIGN Master Thesis By Kun Liu Abdirahman Hirsi-Division of Electric Power Engineering Department of Energy and Environment CHALMERS UNIVERSITY OF TECHNOLOGY-Gothenburg, Sweden 2008 

Abstract 

An experimental half bridge converter setup is designed in order to explore the switching characteristics and losses of a new type of IGBT module. A specific digital control circuit and a drive circuit for an IGBT are designed and integrated into one PCB which can provide different kinds of precise IGBT gate signals. The switching characteristics and losses are investigated under different parameters both in a hardware and a simulation. It can be observed that the switching losses are increasing with the increase of voltage and current levels. Increasing the gate resistance also tends to increase the IGBT switching losses, while the reverse recovery losses of the free-wheeling diode decrease. The switching characteristics of the IGBT are not affected by temperature, but the reverse recovery losses increase with the temperature. The stray inductance has a negative effect, since it causes the oscillation both in the voltage and current waveforms.

 LINK1 : https://www.mediafire.com/file/dpy9vooyx34f23h/IGBT-THESIS.pdf/file

LINK2: https://mega.nz/file/BMFXHRKJ#7gVHFUzX568UFvwuPZWM4YL5t0X-JcTThyXNjN7WBcE 

동북아 슈퍼그리드의 HVDC 계통 및 고장 해석 연구- A study on the HVDC system and fault analysis of the Northeast Asian Supergrid-BY MOON BYUNG-SOO - Department of Electrical Engineering Graduate School of Chosun University

 

 ABSTRACT 

A Study on the HVDC System and Fault Analysis of the Northeast Asian Supergrid MOON BYUNG-SOO Advisor: Prof. Choi Hyo-Sang Ph.D. Department of Electrical Engineering Graduate School of Chosun University

 The thesis's topic is “A study on the HVDC system and fault analysis of the Northeast Asian Supergrid.”In the 21st century, as energy conversion accelerates due to global warming and fossil fuel depletion, the establishment of a supergrid linking power grids among countries is emerging as a major concern. Northeast Asia is rich in renewable energy resources such as wind and solar power in Mongolia and the interior of China, and is geographically adjacent to large-scale power demands in Korea, Japan, and China, providing favorable conditions for cross-border power supply and demand balancing. As a result, strategies for securing energy security and realizing carbon neutrality by 2050 are being developed, and to achieve these goals, it is necessary to establish measures to address the issues of frequency differences among AC systems when linking power grids among countries and the increase in fault current that occurs when connecting to high-voltage direct-current (HVDC) systems. In this paper, the characteristics of fault currents generated in the HVDC transmission system were analyzed, and the applicability of reduction technology was reviewed. In chapter 2, sections 1 and 2, the technical trends of the HVDC transmission system, the transmission methods and interconnection schemes, and the basic principles and modulation techniques of the VSC-HVDC system were examined to present the system configuration direction suitable for HVDC connection. Section 3 systematically summarized the principle of superconducting fault current limiters (SFCLs), DC interruption theory, types of DC interruption technologies, and the operating principles of DC circuit breakers (DCCBs). Section 4 describes the fault analysis theory for the high voltage alternating current (HVAC) system and the specification of fault current calculation based on the IEC 60909. In addition, the basic theories of unbalanced faults such as single-line-to-ground, double-line-to-ground, line-to-line, and three-phase faults, and protection relay were described. In chapter 3, PSCAD/EMTDC simulation design and interpretation were conducted. In section 1, simulation parameters for the application of the symmetric coordinate method were set up. Using this parameter, a symmetric component (P–N–Z) analysis based on the x-axis was performed on the three-phase asymmetric failure types of one-line ground fault, two-line ground fault, and line-to-line short circuit. Using this, electrical characteristics such as instantaneous values of voltage and current for each failure type, unbalance, and change in symmetric components were analyzed. In section 2, an VSC-HVDC grid based on the modular multi level converter (MMC) was constructed between Weihai, China and Taean, Korea, and its parameters were defined. In section 3, the DC voltage, current, and power graphs of MMC were analyzed by steady-state simulation, and the voltage, current, and power characteristics of AC1 (Weihai, China) and AC2 (Taean, Korea) were analyzed. In section 4, a transient state simulation was executed in a PSCAD/EMTDC environment, and the characteristics of the VSC-HVDC system based on a MMC. Also the DC transmission system, and the AC1 and AC2 systems were analyzed. By setting four fault points (F1-F4) in the HVDC ±500 kV, 350 km transmission section, the DC ground current generated during the one-line ground failure of the P (+) and N (-) poles, and the AC voltage, current, and power characteristics of the sending point and the receiving point were analyzed. In addition, the voltage, current, and power characteristics of the AC1, AC2, and DC systems were analyzed in the event of a one-line ground fault, two-line ground fault, between lines, and three-phase short circuits of the AC1 and AC2 systems.

FULL THESIS:https://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=58a12d105532aee7ffe0bdc3ef48d419&keyword=HVDC 

Research on Control Strategy of High-power Three-phase Combined Inverter = 고전력 삼상 복합 인버터 제어 전략 연구 -BY ZHANG HUAYING-Department of Electrical Engineering Graduate School of Konkuk University

Research on Control Strategy of High-power Three-phase Combined Inverter = 고전력 삼상 복합 인버터 제어 전략 연구 -BY ZHANG HUAYING-Department of Electrical Engineering Graduate School of Konkuk University 

ABSTRACT Research on Control Strategy of High-power Three-phase Combined Inverter Zhang Hua Ying Department of Electrical engineering Graduate School of Konkuk University 

Three-phase voltage-type inverters are used in various occasions, such as static reactive power compensator, uninterruptible power supply distribution network development system, motor control, etc. In today's world where energy is scarce, research on inverters and their control technology is of great significance and is gaining more and more attention. People have higher and higher requirements for inverter power supplies. High-performance, high-reliability high-power inverters are one of the development trends of inverter power supplies. In the high-power inverter power supply, the current on the main circuit power device is relatively large, which can reach hundreds of amps, or even thousands of amps. There are two main ways to increase the capacity of the inverter power supply. And parallel technology using inverters to achieve power modularity. This article takes 30kVA combined three-phase inverter as the research object, adopts PID control method, mainly studies the waveform control of high-power three-phase inverter, and focuses on the main circuit structure and system of high-power three-phase inverter. The mathematical model and waveform control were analyzed and studied in detail. The structure of the three-phase combined inverter suitable for high power is analyzed, the main circuit design of the combined threephase inverter with 30KVA is given, and the combined three-phase inverter established and analyzed under different coordinate systems The mathematical model of the model is simulated and studied according to vi the parameter settings.

ORIGINAL LINK :https://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=ef54d3a0876fa98cffe0bdc3ef48d419&keyword=INVERTER 

65 anos de UFSM: entrevista com o reitor Luciano Schuch-Reitor entre 2022 e 2025, Schuch destacou-se por investimentos na inovação, qualidade de trabalho na universidade e incentivo no aumento de índices

 

Em celebração aos 65 anos da Universidade Federal de Santa Maria (UFSM), comemorados em 14 de dezembro de 2025, a Agência de Notícias e a TV Campus, vinculadas à Coordenadoria de Comunicação Social, lançaram a série “Direto do Gabinete”, um conjunto de entrevistas com as ex-reitorias da instituição. Publicadas em formato multimídia, as produções buscam valorizar a memória da Universidade e salientar os principais avanços na trajetória de cada gestão. O sétimo entrevistado da série é o professor Luciano Schuch, décimo segundo reitor da UFSM, entre 2022 e 2025. Formado em Engenharia Elétrica pela Instituição, Schuch foi vice-reitor na gestão de Paulo Burmann, entre 2018 e 2021. Sua gestão buscou fortalecer o ecossistema de inovação da UFSM, implementou o Programa de Gestão e Desempenho (PGD) e incentivou o aumento dos índices de qualidade dos cursos.

 ORIGINAL LINK:https://www.ufsm.br/2025/12/22/65-anos-schuch