• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.470-471
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• 2014

본 논문은 에너지 저장장치를 태양광 발전 시스템에 적용시에, 필요한 충전 균형회로를 전력조절기와 통합시키는 방법에 관한 것이다. 기존의 방식은 전력조절기와 별도로 충전 균형회로를 이용하게 되는데, 이는 복잡한 구성을 필요로 하고, 단가 상승의 원인이 된다. 본 논문에서는 태양광 전력변환 시스템 제작 단가를 낮추기 위해 태양광 모듈을 저장장치와 함께 직렬형 구조로 구성한 뒤 적절히 결선하여, 태양광 전력조절기를 셀 밸런싱 회로로 사용하는 방법을 제안하며, 이를 48W 하드웨어 제작 및 실험을 통해 검증하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.4
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• pp.326-333
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• 2011

This paper studies battery charging methods using existing motor inductance and 3-phase inverters without an additional charger to charge the battery of Plug-in Hybrid Electric Vehicles (PHEVs). As inverter switch control and motor coil used as the energy storage device for boosting make the system the boost converter, the additional charger is eliminated and volume, weight, and cost for the charger are reduced. Various charging methods according to topologies of the system and configurations of the controller are analyzed and verified by PSIM simulation.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.323-324
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• 2012

최근 전력의 공급신뢰도의 하락으로 인하여 기존 송배전 설비의 신규건설 및 유지보수를 위한 투자의 필요성이 더욱 증대되고 있다. 이에 적절한 대안으로서 배터리를 이용한 에너지 저장 시스템(BESS, Battery Energy Storage System)이 대두되고 있다. 본 논문에서는 송배전 설비 투자 지연을 위한 BESS의 필요성에 대해 살펴보고 그 핵심 구성 요소인 PCS의 기능과 최신 동향에 대해 기술한다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.36-37
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• 2010

This paper presents a simulation model and results of experiment about analysis of grid-tied wind turbine generator with batteries. The system consists of two inverters and a bidirectional DC/DC converter. These inverters are to capture the maximum active power under varying wind conditions and to keep the DC-link voltage magnitude at a specific level. And the bidirectional DC/DC converter makes battery charging or discharging depend on power gap between wind turbine output and local load.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.199-208
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• 2017

Lithium polymer batteries are used in energy storage systems (ESS), electric vehicles (EVs), etc. due to their high safety, fast charging and long lifecycle, and now they are used in agricultural drones. However, when overcharging and overdischarging, the lithium-polymer battery is destroyed in the gap structure in the lithium-ion battery and the battery life is reduced. In order to prevent overcharge and overdischarge, uneven cell voltage Cell balancing system is needed. In this paper, a fuzzy controller suitable for nonlinear systems is proposed by detecting the unbalanced cells by detecting the voltage difference between charging and discharging of each cell, and suggesting the applied cell balancing algorithm. In this paper, we have designed the cell balancing of the battery pack of agricultural drones by fuzzy control and it is designed for equal control between cells. As a final result, we checked whether cell balancing is good, and when there are two cells, Cell balancing was confirmed. We tested whether it could be used for other products. As a result, we confirmed that cell balancing is good regardless of the number of cells used.

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.119-125
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• 2011

In this paper, we have studied about minimizing the Energy Storage System (ESS) capacity for mitigating the fluctuation of Wind Turbine Generation System (WTGS) by using Electric Double Layer Capacitor (EDLC) and Battery Energy Storage System (BESS). In this case, they have some different characteristics: The EDLC has the ability of generating the output power at high frequency. Thus, it is able to reduce the fluctuation of WTGS in spite of high cost. The BESS, by using Li-Ion battery, takes the advantage of high energy density, however it is limited to use at low frequency response. To verify the effectiveness of the proposed method, simulations are carried out with the actual data of 2MW WTGS in case of worst fluctuation of WTGS is happened. By comparing simulation results, this method shows the excellent performance. Therefore, it is very useful for understanding and minimizing the ESS capacity for mitigating the fluctuation of WTGS.

• Annual Conference of KIPS
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• 2012.11a
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• pp.40-41
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• 2012

친환경 에너지가 이슈가 되면서 버려지는 에너지를 유용하게 사용하는 에너지 수확기술에 대한 연구가 진행되고 있다. 특히 밀도가 낮은 에너지를 수집하여 저장하는 장치에 대한 연구가 활발하다. 하지만 대부분의 전원관리 회로가 수동적인 회로로 이루어져 있어 여러 상황에 대처하기에는 부족함이 있다. 본 논문은 저전력 마이크로프로세서를 이용하여 계속적으로 배터리 대용의 대용량 캐패시터의 전압을 점검, 관리하는 시스템을 제안하고자 한다. 이를 통하여 변화하는 환경에 맞추어 캐패시터의 전압 수준을 효과적으로 제어할 수 있을 것으로 예상한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.247-252
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• 2015

The majority of electric power in the domestic manned islands with off-grid power system is supplied by the diesel generators. However, in the case of off-grid islands the fuel cost is more expensive to inland areas and difficult to transport them to islands. So the development of renewable energy system using natural resource have been recently introduced. But renewable energy that depend on the natural environment, it is necessary to organized the hybrid system with existing diesel engine because the energy is difficult to maintain stable electric power. This paper presents the results of a feasibility study of hybrid system with energy storage system such as wind, solar, battery and diesel engine. The study included off-grid island as the Seogeochado islands located in Jeolanamdo Province. And, the paper proposed a optimal capacity of hybrid system configuration to maintain carbon free with minimum investment cost. the analysis of economic adaptability performed by HOMER program.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.95-96
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• 2014

본 논문에서는 KEPCO가 신안 팔금도에서 진행 중인 능동배전망 운영실증 관련 2MW급 태양광발전 출력 안정화, 비상발전기, 계통 역률제어 등이 가능한 1MW/1MWh급 ESS의 설계 및 적용 결과를 기술하였다. 1MW/1MWh급 ESS는 외부환경으로부터 시스템 보호를 위해 공조설비 및 소방설비를 포함한 컨테이너에 ESS 관리 및 제어를 위한 PMS, 전력변환을 위한 PCS, 에너지 저장을 위한 배터리 시스템 등을 구성하였다. 또한 배전선로에 ESS 시스템 연계를 위해 변압기, 스위치기어 등의 계통연계설비를 함께 구성하였다. MW급 대용량 전력 시험설비를 이용하여 1MW/1MWh급 ESS의 다양한 기능 및 성능을 검증 후 신안 팔금도 현장에 적용하였다.

• Journal of Hydrogen and New Energy
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• v.25 no.3
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• pp.311-318
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• 2014

Performance degradation of a battery in 20 kWh energy storage system (ESS) under various operating conditions was studied. And energy saving of the ESS was also monitored by connecting with 20 kW photovoltaic (PV). PV-connected ESS saved 5~7% of energy consumption in 2013 compared to that without such system in 2012. As charge-discharge cycle increased, capacity decreased and the performance degradation was glaringly obvious after 40 cycles. And as charge and discharge rate increased, the performance degradation was more serious. After 50 charge-discharge cycles, a lot of degraded product was deposited on the surface of anode and cathode electrodes, and the cathode side was more contaminated. Therefore, in order to maintain the cell performance, it was more important to protect the degradation of the cathode side.