• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1412-1413
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• 1996

Li ion battery have many advantages such as high energy density, high voltage and low self discharge, so it will replace conventional Ni/Cd battery. But, charge-discharge characterization of Li battery is controlled by weight ratio of electrodes (Cathode/Anode). So, we performed a study on relation between charge/discharge characterization and weight ratio (cathode/anode).

• Journal of Power Electronics
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• 제18권3호
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• pp.910-922
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• 2018

Conventional battery state-of-charge (SoC) estimation methods either involve sophisticated models or consume considerable computational resource. This study constructs an enhanced coulomb counting method (Ah method) for the SoC estimation of lithium-ion batteries (LiBs) by expanding the Peukert equation for the discharging process and incorporating the Coulombic efficiency for the charging process. Both the rate- and temperature-dependence of battery capacity are encompassed. An SoC mapping approach is also devised for initial SoC determination and Ah method correction. The charge counting performance at different sampling frequencies is analyzed experimentally and theoretically. To achieve a favorable compromise between sampling frequency and accumulation accuracy, a frequency-adjustable current sampling solution is developed. Experiments under the augmented urban dynamometer driving schedule cycles at different temperatures are conducted on two LiBs of different chemistries. Results verify the effectiveness and generalization ability of the proposed SoC estimation method.

• 전기화학회지
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• 제11권1호
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• pp.33-36
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• 2008

본 연구에서는 겔식 VRLA (valve regulated lead acid번지의 충전상태(SoC) 판단을 위해 임피던스 기법을 이용하여 조사하였다. 임피던스는 VRLA전지 (2V/1.2Ah)의 다양한 충전상태에서 진폭 10mV로 100kHz에서${\sim}$10mHz까지 측정하였다. 측정된 임피던스 데이터로부터 등가회로를 유도하고, CNLS (Complex Non-linear Least Squares) 법을 사용하여 분석하였다. 양극 쪽의 전하전이 저항과 전기이중층 커패시턴스가 음극보다 높았다. 겔 저항은 충전상태가 감소함에 따라 증가하며 이는 VRLA 전지의 충전상태를 판단하는데 중요한 파라미터임을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.222-225
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• 1999

Started upon it discovery by Wright et al in 1973, studies on the solid polymer electrolyte are being carried out vigorously. So, models of Li-polymer battery have been developed through R-L-C components combination and P-spice functional block in this paper. The impedance characteristics of Li-polymer battery with R-L-C components are presented. Simulation results using P-spice functional model are compared with measured charge/discharge characteristics.

• Journal of Power Electronics
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• 제15권4호
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• pp.1105-1118
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• 2015

Battery energy storage devices (ESDs) have become more and more commonplace to maintain the stability of islanded power systems. Considering the limitation in inverter capacity and the requirement of flexibility in the ESD, the droop control was implemented in paralleled ESDs for higher capacity and autonomous operation. Under the conventional droop control, state-of-charge (SoC) errors between paralleled ESDs is inevitable in the discharging operation. Thus, some ESDs cease operation earlier than expected. This paper proposes an adaptive accelerating parameter to improve the performance of the SoC error eliminating droop controller under the constraints of a microgrid. The SoC of a battery ESD is employed in the active power droop coefficient, which could eliminate the SoC error during the discharging process. In addition, to expedite the process of SoC error elimination, an adaptive accelerating parameter is dedicated to weaken the adverse effect of the constraints due to the requirement of the system running. Moreover, the stability and feasibility of the proposed control strategy are confirmed by small-signal analysis. The effectiveness of the control scheme is validated by simulation and experiment results.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.2043-2050
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• 2017

This paper presents two MPC (Model Predictive Control) based charging and discharging algorithms of BESS (Battery Energy Storage System) for capacity firming of wind generation. To deal with the intermittency of the output of wind generation, a single BESS is employed. The proposed algorithms not only make the output of combined systems of wind generation and BESS track the predefined reference, but also keep the SoC (State of Charge) of BESS within its physical limitation. Since the proposed algorithms are both presented in simple if-then statements which are the optimal solutions of related optimization problems, they are both easy to implement in a real-time system. Finally, simulations of the two strategies are done using a realistic wind farm library and a BESS model. The results on both simulations show that the proposed algorithms effectively achieve capacity firming while fulfilling all physical constraints.

• 전력전자학회논문지
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• 제16권3호
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• pp.227-233
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• 2011

본 논문은 5kW 배터리 충전기용 3상 인터리브드 DC-DC 컨버터 설계 및 실험에 대하여 서술하였으며, 배터리 시스템은 풍력 시스템의 안정화를 위해 사용한다. 배터리 충전기는 배터리, 3상 인터리브드 양방향 DC-DC 컨버터, 직류단, 계통연계형 인버터로 구성된다. 납축전지는 matlab으로 간단한 R-C모델링 하였으며, 스텝 전류 방전 실험에 따라 배터리 파라미터를 구하였다. 3상 인터리브드 DC-DC 컨버터를 이용해 배터리의 전류 리플을 감소시켰으며, 5kW 배터리 충전기를 제작하여 충·방전모드 제어기를 설계하고 실험하였다.

• 한국재료학회지
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• 제16권3호
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• pp.193-197
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• 2006

The sodium/sulfur(Na/S) battery has many advantages such as high theoretical specific energy(760Wh/kg), and low material cost based on the abundance of electrode material in the earth. It has been reported that the electrochemical properties of sodium/sulfur cell above $300^{\circ}C$, utilized a solid ceramic electrolyte and liquid sodium and sulfur electrodes. A lot of researches have been performed in this field. Recently, Na/S battery system was applied for electricity storage system for load-leveling. One of severe problems of sodium/sulfur battery was high operating temperature above $300^{\circ}C$, which could induce the explosion and corrosion by molten sodium, sulfur and polysulfides. In order to develop sodium battery operated at low temperature, sodium ion battery has been studied using carbon anode, and sodium oxides cathodes. However, the energy densities of the sodium ion batteries were much lower than high temperature sodium/sulfur cell. In this study, the sodium/sulfur battery with 1M $NaCF_3SO_3$ is tested at room temperature. The charge-discharge mechanism was discussed based on XRD, DSC, SEM and EDS results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.497-500
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• 1997

Conducting polymer is new material in lithium secondary battery. conducting polymer has a lot of merit which is flexible and good handing so that this material is used battery system, solid polymer electrolytes airs used PEO(Polyethylene oxide) and PEO/PMMA branding material adding by liquid plasticizer or lithium salt polymer electrolyte which is added liquid plasticizer, lithium salt decreased the crystallity and thermal stability is over than 13$0^{\circ}C$. it is very useful tn apply lithium secondary battery system.

• 전자통신동향분석
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• 제35권2호
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• pp.69-78
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• 2020

Small portable devices such as mobile phones and laptops currently display a trend of high power consumption owing to their characteristics of high speed and multifunctionality. Low-power SoC design is one of the important factors that must be considered to increase portable time at limited battery capacities. Popular low power SoC design techniques include clock gating, multi-threshold voltage, power gating, and multi-voltage design. With a decreasing semiconductor process technology size, leakage power can surpass dynamic power in total power consumption; therefore, appropriate low-power SoC design techniques must be combined to reduce power consumption to meet the power specifications. This study examines several low-power SoC design trends that reduce semiconductor SoC dynamic and static power using EDA tools. Low-power SoC design technology can be a competitive advantage, especially in the IoT and AI edge environments, where power usage is typically limited.