• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2134-2141
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• 2014

This paper addresses on a wind power system with BESS(Battery Energy Storage System). The concerned system consists of four parts: the wind speed production model, the wind turbine model, configure capacity of the battery energy storage, battery model and control of the BESS. First of all, we produce wind speed by 4-component composite wind speed model. Secondly, the maximum available wind power is determined by analyzing the produced wind speed and the characteristic curve of wind power. Thirdly, we configure capacity of the BESS according to wind speed and characteristic curve of wind speed-power. Then, we propose a control strategy to track the power reference. Finally, some simulations have been demonstrated to visualize the feasibility of the proposed methodology.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1003-1007
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• 1987

The system start-up function of TDX-1A that should be executed during installation or emergency has been designed to meet requirements of the distributed real time control system. It is performed in a centralized manner by the dedicated processor according to the maintenance and administration mechanism of the system. Upon execution, it provides information on the system state for the ESS personal. In additions, it protects the loss the charging and statistics data, and minimizes the effect on the customer service. This paper describes the design concept of the system startup function and its implementation method and also calculates its the execution time.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1639-1642
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• 1997

In this paper, the autonomic function analysis system was designed to noninvasively assess the autonomic function of cardiovascular system. Orthostatic stress protocol was designed to stimulate the autonomic nervous system. designed protocol and analysis algorithm were evaluated by experiments for 25 normal subjects and 22 hemiplegia patients. Data were processed by usign the power spectral analysis. Nwe indexes of autonomic function, LF$_{N}$ and HF$_{N}$, were proposed and were compared with LF/HF ratio. New indexes of the sympathetic and parasympathetic activity, respectively. The IST and the DPT are balanced and have positive value for normal subjects during orthostatic stress but not for hempilegia patients. This result suggest that the IST and the DPT are used as new criteria of normal autonomic function during orthostatic stress.ess.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.176-181
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• 2015

In the DC electric railway system, the effective use of regenerative break energy is an important issue. Since regenerative break energy causes voltage rise or drop in the system, it should be also solved effectively. To solve the problems, applying electric double layer capacitor (EDLC) or voltage source converter (VSC) to the DC electric railway system has been studying. In this paper, the coordination of EDLC and VSC is proposed to solve the problem effectively with its coordinated control algorithm. The proposed method is tested to show its feasibility using Matlab/Simulink.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.521-522
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• 2015

Many countries concern about environmental problems. Therefore, they have made regulation for mandatory reduction of greenhouse gases. Electric Vehicles(EVs) are one of the most effective counterproposals for it. EVs are usually charging for it by using actual distribution system of the Korea Electric Power Corporation(KEPCO). However, it could cause adverse effects such as increase of the power demand and voltage variation on the distribution system. To reduce adverse effects for demand power side, in this paper, charging for EVs by using PV(Photovolatic Power Generation) connected with ESS(Energy Storage System) are modeled by using Electro Magnetic Transient Program(EMTP). And then, the simulation results are compared with EVs that are connected to the distribution system of KEPCO for using charge.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2161-2166
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• 2008

This paper deals with a Z-source active power filter(Z-AFU) for mitigation voltage THD(total harmonic distortion) due to voltage harmonic propagation(amplification) in 6.6kv power distribution system. Bus voltage harmonic signal is detected by 60Hz butterworth BPF(band pass filter). As an ESS(energy storage system) of the proposed system, PEM fuel cells(Ballard NEXA, 1.2kw) is employed. Test results based on PSIM(power electronics simulation tool) validate the proposed approach.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.329-335
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• 2018

In an electric vehicle and Energy Storage System(ESS), a large number of batteries are connected in series or parallel to obtain high voltage and current. The battery management system(BMS) is needed because battery has a characteristic that explode in overcharging and overcurrent situations due to the nature of the battery material and the battery life is dramatically reduced when the battery is overdischarged below the specified voltage. In this paper, we proposed a system that can manage a large amount of batteries through the communication of master-slave type with multiple microcontroller. We confirmed the stable operation of the proposed system through the balancing-charging and storage mode experiments.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.422-423
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• 2019

In accordance with the Carbon-Free Island by 2030 policy of Jeju Special Self-Governing Province, renewable energy sources are increasing in Jejudo Island. Due to the intermittent output characteristics of wind turbines, one of the renewable energy sources, which can cause unbalanced system conditions between the demand load and the power generation of Jejudo Island. The Korea Power Exchange limits the output of wind turbines for stabilizing the Jeju power system. Therefore, this paper proposes a method to supply a limited output of Sangmyeong Wind Farm in Jeju Power system to Energy Storage System(ESS) and Water Electrolysis Device(WED). The voltage and frequency fluctuation of the Jeju power system is checked accordingly. The simulation results are performed using the PSCAD/EMTDC program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.585-593
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• 2020

Until now, 29 fire accidents have occurred; 22 of them were caused by the interconnection of renewable energy sources that occurred during the rest period after the lithium-ion battery had been fully charged regardless of the seasons. The fire accidents of ESS were attributed to thermal runaway due to the overcharging of a few cells with the phenomenon of self-energy balancing, which is unintentional current flow from cells with a high SOC to the low cells if the SOC condition of each cell connected in parallel is different. Therefore, this paper proposes a novel configuration and operation algorithm of the BMS to prevent the self-energy balancing of ESS and presents a hybrid SOC estimation algorithm. From the test results of the self-energy balancing phenomenon between aging and normal cells based on the proposed algorithm and BMS, it was confirmed the possibility of self-energy balancing, which is unintentional current flow from cells with a high SOC to cells with a low SOC. In addition, the proposed configuration of the BMS is useful and practical to improve the safety of lithium-ion batteries because the BMS can reliably disconnect a parallel connection of the cells if the self-energy balancing current becomes excessively high.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.782-785
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• 2011

Needs for MG(Microgrid) development are increasing all over the world as a solution to the problems including the depletion problem of energy resources, the growing demand for electric power and the climatic and environmental change. Especially Photovoltaic power is one of the most general renewable energy resources. However there is a problem of the uniformity of power quality because the power generated from solar light is very sensitive to climate fluctuation (variation of insolation and duration of sunshine, etc). As a solution to the above problem, ESS(Energy Storage System) is considered generally, but it has some limitations. To solve this problem this paper suggests a hybrid estimation method of photovoltaic power generation according to two climatic factors, i.e. insolation and sunshine. This result seems to help design the appropriate capacity of ESS and estimate the proper switching time between DC and AC power in the premises power system and thus maintain the uniformity of power quality.