AUTOR DO BLOG ENG.ARMANDO CAVERO MIRANDA SÃO PAULO BRASIL
.gif)
“GRAÇAS A DEUS PELA VIDA,PELA MINHA FAMÍLIA,PELO TRABALHO.PELO PÃO DE CADA DIA,POR NOS PROTEGER DO MAL”
“SE SEUS PROJETOS FOREM PARA UM ANO,SEMEIE O GRÂO.SE FOREM PARA DEZ ANOS,PLANTE UMA ÁRVORE.SE FOREM PARA CEM ANOS,EDUQUE O POVO”
https://picasion.com/
quarta-feira, 16 de setembro de 2026
Do Brasil para Kassel: Três estudantes conquistam o Prêmio Estadual de Energia-colaboração entre a Universidade de Kassel, a Universidade Federal do Ceará (UFC) e a Universidade Federal de Campina Grande (UFCG), no Brasil
Trends in Isolated Power Converters Using High-Frequency Transformers Takaharu Takeshita*,a, Fellow Wataru Kitagawa*, Senior Member Kohei Budo-Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan
Department of Electrical and Mechanical Engineering, Nagoya Institute
of Technology, Gokiso, Showa, Nagoya 466-8555, Japan
**Department of Electrical, Electronic and Computer Engineering, Gifu
University, 1-1 Yanagido, Gifu City 501-1193, Japan
This paper surveys recent trends in isolated power converters using high-frequency transformers, which are used in DC power
distribution systems and chargers for electric vehicles, etc. This paper explains the trends in the magnetic materials used in highfrequency
transformers for galvanic isolation, the circuit configurations of DC-DC and AC-DC converters using high-frequency
transformers, and isolated modular multilevel converters for large capacity applications. © 2026 Institute of Electrical Engineers
of Japan and Wiley Periodicals LLC.
ORIGINAL LINK :https://onlinelibrary.wiley.com/doi/epdf/10.1002/tee.70259
Evaluation of Magnetic Materials for Very High Frequency Power Applications Yehui Han, Member, IEEE, Grace Cheung, An Li, Charles R. Sullivan, Member, IEEE, and David J. Perreault, Senior Member, IEEE
Evaluation of Magnetic Materials for Very High Frequency Power Applications Yehui Han, Member, IEEE, Grace Cheung, An Li, Charles R. Sullivan, Member, IEEE, and David J. Perreault, Senior Member, IEEE
Abstract—This paper investigates the loss characteristics of rf
magnetic materials for power conversion applications in the 10
MHz to 100 MHz range. A measurement method is proposed
that provides a direct measurement of inductor quality factor
QL as a function of inductor current at rf frequencies, and
enables indirect calculation of core loss as a function of flux
density. Possible sources of error in measurement and calculation
are evaluated and addressed. The proposed method is used to
identify loss characteristics of several commercial rf magnetic
core materials. The loss characteristics of these materials, which
have not previously been available, are illustrated and compared
in tables and figures. The use of the method and data are
demonstrated in the design of a magnetic-core inductor, which is
applied in a 30 MHz inverter. The results of this paper are thus
useful for design of magnetic components for very high frequency
(VHF) applications.
Index Terms—Magnetic materials, resonant inductor, very high
frequency (VHF), Steinmetz parameters.
I. INTRODUCTION
There is a growing interest in switched-mode power electronics
capable of efficient operation at very high switching
frequencies (e.g., 10 – 100 MHz). Power electronics operating
at such frequencies include resonant inverters [1]–[10] (e.g.,
for heating, plasma generation, imaging, and communications)
and resonant dc-dc converters [1], [3], [11]–[20] (which utilize
high frequency operation to achieve small size and fast transient
response.) These designs utilize magnetic components
operating at high flux levels, and often under large flux
swings. Moreover, it would be desirable to have improved
magnetic components for rf circuits such as matching networks
[21]–[25]. There is thus a need for magnetic materials and
components suitable for operation under high flux swings at
frequencies above 10 MHz.
Unfortunately, most magnetic materials exhibit unacceptably
high losses at frequencies above a few megahertz. Moreover,
the few available bulk magnetic materials, which are
potentially suitable for frequencies above 10 MHz, are typically
only characterized for small-signal drive conditions, and
Y. Han is with the University of Wisconsin-Madison, 2559C Engineering
Hall, 1415 Engineering Drive, Madison, WI 53706 USA (e-mail:
yehui@engr.wisc.edu).
G. Cheung is with Intersil Corp (e-mail: gmcheung@gmail.com).
A. Li is with Massachusetts Institute of Technology, MA 02139 USA (email:
anli@mit.edu).
C. R.
terça-feira, 15 de setembro de 2026
태양광 시스템과 BESS를 적용한 직류 배전 시스템에 관한 연구 = A Study on DC Distribution System Applying Battery Energy Storage System and Solar Energy System-Jung Ho-chul Department of Electrical Engineering Graduate School Yeungnam University
태양광 시스템과 BESS를 적용한 직류 배전 시스템에 관한 연구 = A Study on DC Distribution System Applying Battery Energy Storage System and Solar Energy System
Jung Ho-chul
Department of Electrical Engineering
Graduate School
Yeungnam University
( Supervised by professor Sang-Bong Rhee )
This thesis study the Direct-Current(DC) distribution system along with Battery Energy Storage System(BESS) and Solar Energy system. Power conversion from Alternative current(AC) to DC has bad influence on the power supply reliability. Therefore, it is required to reduce power loss in order to supply it to the DC load efficiently by constituting the DC distribution system. This thesis models an AC/DC converter which converts the power from existing AC system to DC system, DC/DC converters, BESS system, Building Integrated Photovoltaic System(BIPV), and Roof-Top Photovoltaic solar energy system for uninterruptible power supply in case of fault in system.
Electromagnetic Transient Program (EMTP)/ATPDraw has been used to model each system individually first and then the all systems are integrated and modeled, to verify the operational characteristic considering all possible modes of operation. It is deduced from the simulation result that the performance of proposed system is perfect.
These results are expected to contribute to the researchers for the analysis and design of DC distribution system in the future.
ORIGINAL LINK:
segunda-feira, 14 de setembro de 2026
A Study on Safety Assessment Regarding Battery Fire and Explosion Risks for the Application of Battery Energy Storage Systems (BESS) to Ships-배터리 에너지 저장시스템(BESS)의 선박 적용을 위한 배터리 화재·폭발 안전성 평가에 관한 연구
A Study on Safety Assessment Regarding Battery Fire and Explosion Risks for the Application of Battery Energy Storage Systems (BESS) to Ships-배터리 에너지 저장시스템(BESS)의 선박 적용을 위한 배터리 화재·폭발 안전성 평가에 관한 연구
Abstract
Due to the International Maritime Organization's (IMO) tightened environmental regulations, ship propulsion systems are shifting toward eco-friendly technologies, leading to the expanded adoption of Battery Energy Storage Systems (BESS). Shipboard BESS are implemented for purposes such as propulsion assistance, peak load shaving, and energy efficiency improvement; they operate through the integration of various components, including battery cells, Battery Management Systems (BMS), Power Conversion Systems (PCS), and Energy Management Systems (EMS). In particular, Lithium-ion batteries (LIBs) are widely adopted as the core component of BESS due to their excellent characteristics, such as high energy density, long lifespan, and high charge/discharge efficiency. However, because LIBs contain flammable electrolytes, they pose potential risks of fire or explosion in the event of abnormal conditions—such as external impact, internal short circuits, or thermal runaway. These characteristics, combined with the confined spaces, enclosed structures, and limited external firefighting support inherent to ships, make ensuring the fire and explosion safety of BESS a critical technical challenge. Currently, however, most domestic and international classification society regulations are based on land-based IEC standards, with a lack of safety testing criteria that reflect the unique operational environment of ships. Therefore, this study comprehensively evaluated the safety of shipboard BESS—considering their actual operational environment—by conducting safety tests at the cell and module levels under mechanical and thermal abuse conditions, testing for secondary explosions caused by thermal runaway and off-gassing, and assessing a targeted fire suppression system designed for initial fire response. Through this work, the study aims to propose safety measures tailored to the marine environment and provide foundational data for future regulatory improvements. In this study, domestic and international standards were analyzed to ensure the safety of marine battery energy storage systems (BESS), and empirical tests were conducted based on high-risk test items covering mechanical, thermal, and electrical abuse conditions. Evaluations of durability against high temperatures, impact, vibration, and crushing—conducted across various battery types and states of charge—revealed distinct characteristics for each cell type while confirming overall high safety levels. Furthermore, to overcome the limitations of conventional visual inspections, a new evaluation framework incorporating a 48-hour stabilization period and voltage monitoring techniques was proposed; this enables the quantitative diagnosis of subtle damage or performance degradation not visible to the naked eye. These findings underscore the necessity of establishing battery safety evaluation standards optimized for the unique operational conditions of ships and are expected to serve as practical foundational data for future improvements to relevant regulations and testing guidelines.
Secondly, the study assessed the risk of secondary explosions caused by off-gas generated during thermal runaway in marine BESS installation areas and quantitatively analyzed the structural integrity of fire-resistant bulkheads. To this end, cell-level thermal runaway tests were conducted to identify the primary flammable components of the off-gas, and explosion tests using mixed gases experimentally verified the explosive risks associated with the off-gas. Subsequently, based on these results, finite element analysis was performed on an actual vessel to evaluate the structural limit state of the battery room bulkheads. The findings highlighted the necessity of incorporating explosion considerations into effective structural design and ensuring adequate separation distances for battery rooms, providing practical foundational data for future regulatory revisions and the establishment of design standards. Thirdly, considering the difficulty of obtaining external firefighting support during a fire—due to the enclosed structure and spatial constraints of ships—a targeted-injection fire suppression system was proposed for the initial suppression of fires in battery energy storage systems (BESS). To this end, the fire suppression performance of non-aqueous (Novec 1230) and aqueous (F-500) agents was experimentally compared across single- and multi-module configurations. Both agents proved effective in addressing initial thermal runaway; the targeted-injection method, by spraying the agent directly onto the ignition point, effectively prevented fire spread by locally blocking heat release and inhibiting heat transfer. Given the shipboard environment—which necessitates enclosed cabinets and high ingress protection ratings (IP44 or higher)—an internal installation method was found to be more effective than an external supply system. This internal suppression system, integrating thermal runaway detection with targeted injection, could be incorporated into future safety guidelines for marine BESS, contributing to the prevention of reignition and the minimization of structural damage through early-stage fire suppression.
This study employed a multifaceted approach to ensure fire and explosion safety for battery energy storage systems, which are critical components of electric-propulsion ships. Mechanical and thermal abuse tests reflecting actual ship operating conditions were conducted to verify test parameters and the impact of risk factors; additionally, explosion tests were performed to experimentally demonstrate the explosion risks posed by off-gases generated during thermal runaway and to quantitatively assess the associated risk levels. Furthermore, the study experimentally validated the effectiveness of a targeted-injection fire suppression system—optimized for the spatial constraints of ships—in preventing the initial spread of fire, thereby contributing to the development of safety guidelines for shipboard energy systems. The results of this study can serve as an academic and practical foundation for strengthening regulations and technical standards related to the safety assessment of marine batteries.
Assinar:
Postagens (Atom)