• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.297-298
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• 2012

본 논문에서는 장주기(Long-Term, LT) 배터리 에너지 저장 시스템(Battery Energy Storage System, BESS)용 1MW급 PCS의 계통연계형 멀티레벨 컨버터 및 제어 시스템을 소개하고, 현장 시험을 통한 타당성 검증 결과를 제시한다. 또한 1.5 MW 풍력발전기 출력과 연계한 잉여 전력 충전 및 전력 피크 시간대 방전(Energy Shift) 기능을 통해 피크 부하 시간대 전력 문제에 효과적으로 대응할 수 있음을 확인하였다.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1916-1924
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• 2017

Fossil oil, as the main energy of transportation, is destined to be exhausted. The electrification of transportation is a sustainable solution to the energy crisis, since electric power could be acquired from the inexhaustible sun, wind and water. Among all the problems that hinder the development of Electric Vehicle (EV) industry, charging issue might be the most prominent one. In this paper, the service process of a charging station with Battery Energy Storage System (BESS) is analyzed by means of $Cram{\acute{e}}r$ - Lundberg model which has been intensively utilized in ruin theory. The service quality is proposed in two dimensions: the service efficiency and the service reliability. The arrival rate and State of Charge (SOC) upon arrival are derived from 2009 National Household Travel Survey (NHTS). The simulations are performed to show how the service quality is determined by the system parameters such as the number of servers, the service rate, the initial capacity, the charge rate and the maximum waiting time. At last, the economic analysis of the system is conducted and the best combination of the system parameters are given.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.1
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• pp.18-22
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• 2015

When using a secondary battery in energy storage units, if the grid is in light duty the active power is stored so it can be used when the grid is in heavy duty. This makes possible for the load equalize and make the grid optimized. Recently the government is trying to propagate this technology. Depending on its capacity this kind of electric energy storage unit is used in adjusting the frequency, break up the energy peak in summer and winter, stabilize the energy output of renewable energy which can change unstably because of the environment. Which makes it possible to stabilize the grid. It is anticipated that market of 120 trillion won will be developed worldwide in 2030. Currently in Korea a steady supply is in progress. However because of stray electromagnetic waves some other electronics are malfunctioning. This paper covers the research in the method to detect the emission noise in small electric energy storage units using lithium secondary batteries and battery management system, Power conditioning systems with CIPSR standards. And the research of a more efficient method to measure such stray electromagnetic waves.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.72-75
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• 2009

In this paper, lithium-ion-polymer battery based standalone photovoltaic energy storage is presented. conventional system was difficult to choose hi-directional DC-DC converter because of unbalanced voltage of batteries. The other side, lithium-ion-polymer battery hardly contains unbalanced voltage between each batteries. And Lithium Polymer Battery is clean battery because is doesn't contain heavy metals such as Nickel, Cadmium. We analyzed validity of algorithms according to load pattern for the system through the simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.180-183
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• 2000

The Battery Energy Storage System(BESS) has lots of advantages such as load levelling, quick response emergency power(spinning reserve), frequency and voltage control, improvement of reliability, and deferred generation and transmission construction. The economic feasibility requires justification from the customer side of meter to promoting the dissemination of BESS nationally. In this paper, we proposed the economic assessment model of customer owned Battery Energy Storage System(BESS) which is complemented and improved the existing model. The proposed model is applied to the typical customer type(light-industrial commercial, and residential) which are taken from the statistical analysis on the load profile survey of Korea Electric Power COmpany (KEPCO). The economic assessment performed for each customer type to justifying their economic feasibility of BESS installation from the economic measures such as payback period, overall benefits, ROI, and ROR. The results of this paper are useful to the customer investment decision making and the national energy policy & strategy.

• Journal of Power Electronics
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• v.13 no.4
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• pp.516-527
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• 2013

This paper presents a new overall system for state-of-available-power (SoAP) prediction for a lithium-ion battery pack. The essential part of this method is based on an adaptive network architecture which utilizes both fuzzy model (FIS) and artificial neural network (ANN) into the framework of adaptive neuro-fuzzy inference system (ANFIS). While battery aging proceeds, the system is capable of delivering accurate power prediction not only for room temperature, but also at lower temperatures at which power prediction is most challenging. Due to design property of ANN, the network parameters are adapted on-line to the current battery states (state-of-charge (SoC), state-of-health (SoH), temperature). SoC is required as an input parameter to SoAP module and high accuracy is crucial for a reliable on-line adaptation. Therefore, a reasonable way to determine the battery state variables is proposed applying a combination of several partly different algorithms. Among other SoC boundary estimation methods, robust extended Kalman filter (REKF) for recalibration of amp hour counters was implemented. ANFIS then achieves the SoAP estimation by means of time forward voltage prognosis (TFVP) before a power pulse occurs. The trade-off between computational cost of batch-learning and accuracy during on-line adaptation was optimized resulting in a real-time system with TFVP absolute error less than 1%. The verification was performed on a software-in-the-loop test bench setup using a 53 Ah lithium-ion cell.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.381-382
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• 2020

In the battery energy storage system, battery cells are connected in series to increase the operating voltage. Due to the difference in characteristics, the performance degradation of cells is dissimilar. This paper proposes an online DC internal impedance estimation for battery cells in the series string using a matrix-switched capacitor converter, which is already verified as useful for the series balancing of the cells. The simulation in the hardware in the loop test rig shows good accuracy and the feasibility of the proposed method.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.10
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• pp.97-107
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• 2009

Recent technologies of the car are focused on improving vehicle's fuel efficiency and developing alternative energy sources. These technologies bring on the development of hybrid car. On the other hand, because of short driving distance, low efficiency of charging and high price, energy storage system need to improve the storage capability. It is very important to understand the existing technologies, grasp the existing patent and establish the technical target to improve the energy storage system. In this paper, technology trends of energy storage system of the hybrid car are analyzed. This study was based on the applied and registered patent in Korea, Japan, U.S.A and Europe until December 2008. The analyses are divided into two categories: a battery system and charging system of the hybrid car. The facts of the level of technology, trends of the R&D of leading companies, key patents, blank of the technology were analyzed. Finally the future R&D strategy of hybrid car are established.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.20 no.2
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• pp.1-10
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• 2024

The introduction of the sector coupling concept has expanded the scope of ESS utilization, resulting in the importance of thermal management of ESS. To ensure the safe use of the lithium-ion batteries that are used in ESS, it is important to use the batteries at the optimal temperature. To examine the utilization of liquid cooling in ESS, numerical study was conducted on the thermal characteristics of 21700 battery modules (16S2P array) during liquid cooling using Novec-649 as insulating fluid. The NTGK model, an MSMD model in ANSYS fluent, was used to investigate thermal characteristics on the battery modules with liquid immersion cooling. The results show that the final temperature of the battery module discharged at 5 C-rate is 68.9℃ using natural convection and 48.3℃ using liquid cooling. However, the temperature difference among cells in the battery module was up to 0.5℃ when using natural convection cooling and 5.8℃ when using liquid cooling, respectively, indicating that the temperature difference among cells was significantly increased when liquid cooling was used. As the mass flow rate increased from 0.01 kg/s to 0.05 kg/s, the average temperature of the battery module decreased from 48.3℃ to 38.4℃, confirming that increasing the mass flow rate of the insulating fluid improves the performance of liquid immersion cooling. Although partial liquid immersion cooling has a high cooling performance compared to natural convection cooling, the temperature difference between modules was up to 8.9℃, indicating that the thermal stress of the battery cells increased.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.11-18
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• 2017

In order to maintain customer voltages within the allowable limit($220{\pm}13V$) as much as possible, tap operation strategy of SVR(Step Voltage Regulator) which is located in primary feeder, is widely used for voltage control in the utilities. However, SVR in nature has operation characteristic of the delay time ranging from 30 to 150 sec, and then the compensation of BESS (Battery Energy Storage System) during the delay time is being required because the customer voltages in distribution system may violate the allowable limit during the delay time of SVR. Furthermore, interconnection of PV(Photovoltaic) system could make a difficultly to keep customer voltage within the allowable limit. Therefore, this paper presents an optimal coordination operation algorithm between BESS and SVR based on a conventional LDC (Line Drop Compensation) method which is decided by stochastic approach. Through the modeling of SVR and BESS using the PSCAD/EMTDC, it is confirmed that customer voltages in distribution system can be maintained within the allowable limit.