재사용 배터리 ESS 안전 운용 및 성능 검증 시뮬레이션 환경 개발 = Development of Simulation Environment for Safe Operation and Performance Validation of Reused Battery ESS

 

Development of Simulation Environment for Safe Operation and Performance Validation of Reused Battery ESS Park Joonhong Department of Electrical Engineering, Graduate School of Chonnam National University (Supervised by Professor Ahn Seon-ju)

 (Abstract) With the expansion of the used battery market expected around 2030, the promotion of reuse and recycling industries for used batteries has emerged as a critical issue. Battery reuse technology refers to the process of evaluating the remaining capacity and lifespan of secondary batteries, whose full-charge capacity has fallen below a certain threshold after use in electric vehicles (EVs), and repurposing them for other applications such as ESS (Energy Storage Systems) and UPS (Uninterruptible Power Supplies). This technology holds significant value in terms of economic efficiency and resource circulation. Particularly, numerous demonstration studies are being conducted to optimize safe operation and establish system standardization for ESS using reused batteries. This study aims to ensure the safe operation of ESS composed of reused batteries by designing three algorithms necessary for estimating battery status and evaluating health, based on existing research and literature, and examining their application conditions. These algorithms are presented in the form of SOX (State of X, where X = Power, Health, Balance, etc.), and based on this, an operational program menu structure was designed. Additionally, a simulation model was developed to validate the performance of reused battery ESS, identifying key considerations for model design, including capacity deviation, internal parameter variation, degradation rate differences, and thermal factors. Simulated operations were used to verify parts of the algorithms and observe changes in ESS conditions. This study differentiates itself from existing research in two main aspects. First, it involves the actual application of operational data-based battery status estimation algorithms to ESS. Unlike previous studies that primarily focused on laboratory environments or small-scale cell-based tests, this study incorporated factors necessary for applying these algorithms to a 500kWh large-scale ESS composed of reused batteries. Second, it identifies and integrates key considerations for simulation model design to validate the performance of reused battery ESS. Specifically, four essential elements that must be included in the design of reused battery ESS models were defined and applied to the simulation model, providing guidance for future ESS model design utilizing reused batteries. In this study, a safe operation plan for reused battery ESS was developed, and a simulation model for performance validation was created. Furthermore, through simulated operations under various conditions, the study analyzed ESS conditions and confirmed the effectiveness of the algorithms. The results are expected to serve as foundational data for evaluating the safety and performance of ESS in the future.

FULL THESIS

 :https://www.mediafire.com/file/1yd28ry2jnfe3ya/000000075764_20260826213443.en.dual.pdf/file

3상 인버터를 위한 방열판 크기 최적화 -Heat Sink Size Optimization for 3-Phase Inverter-Gwangwoon University Graduate School Department of Electrical Engineering-AUTHOR Seo Yujin

 

3상 인버터를 위한 방열판 크기 최적화 -Heat Sink Size Optimization for 3-Phase Inverter-Gwangwoon University Graduate School Department of Electrical Engineering-AUTHOR Seo Yujin This thesis is submitted as an Engineering Master's Thesis 다국어 초록 (Multilingual 

Abstract) kakao i 다국어 번역 The power loss of the inverter acts as heat. Therefore, heat dissipation design is essential for high-output inverter operation. In this paper, a heat sink size optimization method applicable to all inverter module and heat sink structures is proposed. The capacity of the inverter was selected according to the load conditions, and the input power, output power, switching loss, conduction loss, case temperature, and junction maximum temperature were measured through simulation. Through this, the case temperature and junction temperature according to the loss of the inverter are found, and the appropriate heat sink size is suggested through heat dissipation simulation. The smaller the size of the heat sink, the higher the heat dissipation efficiency at the same power loss. However, if the temperature of the junction of the inverter becomes too high, operation is impossible. Therefore, we find out through simulation how high the operating temperature of the inverter can be with the minimum heat sink size. Create a 3D model of the inverter module and heat sink, apply the loss power derived through inverter simulation, and check the output temperature through simulation while reducing the size of the heat sink. Through this, a method for selecting the minimum size of the heat sink applicable to the inverter module was proposed. 

ORIGINAL LINK KOREAN:

 https://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=de6fb1f6978f0912ffe0bdc3ef48d419&keyword=3%EC%83%81%20%EC%9D%B8%EB%B2%84%ED%84%B0 

Thesis translation from Korean and English:https://www.mediafire.com/file/eybq0nvdhtnik4w/Heat+Sink+Size+Optimization+for+3-Phase+Inverter.pdf/file

 

Effects of Flat-Core Geometry on Magnetic Flux Distribution and Thermal Behavior in Integrated Transformers for High-Frequency LLC Converters- Journal of Electrical Engineering & Technology-BY-Jun-Taek Oh · Taek-Keun Jung · Jong-Soo Kim

 

Effects of Flat-Core Geometry on Magnetic Flux Distribution and Thermal Behavior in Integrated Transformers for High-Frequency LLC Converters Jun-Taek Oh1 · Taek-Keun Jung1 · Jong-Soo Kim1 Received: 18 November 2025 / Revised: 12 April 2026 / Accepted: 27 April 2026 / Published online: 22 May 2026

 © The Author(s) under exclusive licence to The Korean Institute of Electrical Engineers 2026

 Abstract This study investigates the thermal behavior of an integrated transformer structure that incorporates a flat core to expand the flux-sharing area. Using electromagnetic analysis based on Ansys Maxwell, the characteristics of magnetic flux distribution and core temperature rise are analyzed, and the magnetic flux density and thermal behavior are compared according to the presence of the resonant inductor core and variations in flat-core thickness. In addition, the characteristics of flux overlap and saturation according to the direction of flux flow are analyzed. Based on these analyses, an optimized integrated transformer design is proposed to effectively mitigate heat generation and magnetic flux saturation. To verify the feasibility of this design, a 500-kHz LLC resonant converter prototype was built, and experiments were conducted at approximately 3.1 kW in the resonant frequency region. The results show that the optimized design reduces core temperature rise by up to 95.8 °C compared with a conventional design that does not consider flat-core thickness and integrated transformer geometry, while also improving overall system efficiency by 0.7%. These findings demonstrate the effectiveness of the flat-core-based integrated transformer design in high-frequency, high-power-density power conversion systems and highlight its potential applicability to future highly integrated power electronic systems.

VIEW ORIGINAL  FULL ARTICLE : https://link.springer.com/article/10.1007/s42835-026-02795-9

ALTERNATIVE LINK :https://www.mediafire.com/file/u2r54j2fkjxipqb/s42835-026-02795-9.pdf/file

WEBINAR From Grid Following GFL to Grid Forming GFL (Spanish Audio)-Dr.Francisco Gonzalez-Longatt -IEE-UNMSM

 https://youtu.be/O5qq5OkpNHo?si=bH40K4CqfeW0zpoI

 

Title: From Grid Following to Grid Forming Converters Webinar, 2nd April 2026, 5:10 PM (Peru time).

 Abstract Power Electronic converters (PECs) have been in power systems for many decades; however, it is only recently that they have come to account for a significant share of generation, transmission, and demand. PEC has dramatically changed in recent times, from a very limited support role in power system operation to a key element in the transition to a zero-carbon society. The early developments in high-voltage direct current (HVDC) based on Thyristors were a formidable step forward for bulk power transmission. However, the development of more flexible commutation devices and sophisticated control mechanisms, together with appropriate practices and grid codes, is making voltage source converter (VSC)-interfaced technologies a crucial component of modern and future power system operations and paving the way for a secure transition to a zero-carbon society. This short seminar provides a general introduction to power electronic converters and their transition from grid-following to grid-forming, including practical discussions of the importance of several elements and the control philosophy. The seminar includes (but is not limited to) discussing the benefits of a smart grid-friendly converter.

RADIATION TOLERANT POWER ELECTRONICS FOR SPACE APPLICATIONS Doctoral Thesis Jaroslav Laifr Prague, November 2018-Czech Technical University in Prague Faculty of Electrical Engineering Department of Measurement

RADIATION TOLERANT POWER ELECTRONICS FOR SPACE APPLICATIONS Doctoral Thesis Jaroslav Laifr Prague, November 2018 

Abstract: The aim of this thesis is to summarize the state-of-the-art satellite electronics design, find its bottlenecks and propose a novel, scientific-based approaches on the space power systems development addressing rapidly evolving so-called "NewSpace" ecosystem. The modern consumer-driven electronics with rising computational power and miniaturization demands similar to the Moore's Law for computers brings new technological challenges and problems. The NewSpace community needs to understand them to successfully conduct its presence in space, both aboard earth-orbiting and interplanetary missions. It is the satellite (manned and unmanned) and aerospace industry, private or government-led institutions which need to follow the technological and scientific progress by faster steps if want to utilize the full potential of the scientific and technological progress in commercially available markets and technological breakthroughs. Initial studies are the follow-up of the author's Master thesis: Fluxgate Magnetometer for Satellite Attitude Control, carried on within the multi-faculty CubeSat project CzechTechSat led by the author as the Principal Investigator. Students were implementing authors' hypotheses within their bachelor and master thesis terms and supported their research and validation. Key findings were implemented as an practical example of the thesis utilization within the Low Voltage Power Supply unit for the Radio and Plasma Waves Investigation instrument selected to be flown aboard the European Space Agency L-Class mission called JUICE (Jupiter Icy Moon Explorer) into the Jovian system in 2023. Also in the project CRREAT by the realization of the ultra low power dosimeter for small satellites. The thesis is also a base of the spacecraft electronics design E-Book called "NewSpace Economically" prepared to be released to the small satellite community in 2019. Keywords: ESA, RPWI, JUICE, CubeSat, NewSpace, Radiation, Power Supply, Satellite.

ORIGINAL LINK : 

https://dspace.cvut.cz/bitstreams/f1967e19-960c-4e34-9a18-6039da3b856d/download

ENLACE ALTERNATIVO : https://www.mediafire.com/file/6k4gywmdvanik6c/F3-D-2019-Laifr-Jaroslav-Jaroslav_Laifr_Doctoral_Thesis.pdf/file