• 전기학회논문지
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• 제64권2호
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• pp.208-213
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• 2015

This study presents the estimation method for the optimal capacity of BESS(Battery Energy Storage System) in order to reduce the electric charges of common consumer. The daily optimal charge and discharge plan of BESS which satisfies the given constraints is established using linear programming through the change of rated output/rated capacity of the time that shows the electric charges in the highest reduced rate has been selected. There will be a problem to compare only reduced rate because the bigger the rated capacity, the more reduced rate is increased. Therefore, rated output/rated capacity of the time when the reduced amount of electric charges for a year is higher than the investment cost of BESS was selected.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1369-1375
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• 2017

This paper presents an optimal operation scheduling algorithm for a smart home with energy storage system, electric vehicle and distributed generation. The proposed algorithm provides the optimal charge and discharge schedule of the EV and the ESS. In minimizing the electricity costs of the smart home, it considers not only the cost of energy purchase from the grid but also the life cost of batteries. The life costs of batteries are calculated based on the relation between the depth of discharge and life time of battery. As the life time of battery depends on the charge and discharge pattern, optimal charge and discharge schedule should consider the life cost of batteries especially when there is more than one battery with different technical characteristics. The proposed algorithm can also be used for optimal selection of size and type of battery for a smart home.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권7호
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• pp.412-417
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• 2000

This paper offer fundamental materials about Partial Discharge(PD) detection by electromagnetic waves. All spectrum data-usually used as grape- can be used as numbers. And then the average of background noise spectrum strength was made. Average value subtract from every data. Then average value appeared, graphed. The graph was compared with the magnitude of charge. The shape of changes is similar, and the change of electric field strength could be seen in one sight. When the magnitude of charge is over than 100[pC], antenna can detect partial discharge. So this method will be very useful to diagnosis of insulation. It the performance of the antenna used in this experiment is analyzed, good results can be obtained.

• Korean Chemical Engineering Research
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• 제45권3호
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• pp.242-248
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• 2007

자동차 전기장치 시스템을 최적화하기 위해서는 차량용 납축전지의 충전 및 방전 거동을 예측할 수 있는 모델링 기술이 필요하다. 본 연구에서는 유한요소법을 이용하여 차량용 12-V 납축전지의 충전 및 방전 거동을 예측할 수 있는 2차원 모델링을 수행하였다. 이 연구에 사용된 수학적 모델에는 전기화학반응 속도론, 전해질의 유동, 대류에 의한 이온의 전달현상, 전극의 시간에 따른 공극률의 변화 등이 고려되었다. 모델링의 신뢰성을 검증하기 위하여 방전 및 충전실험을 수행하였다. 방전실험은 $25^{\circ}C$에서 C/5, C/10 및 C/20의 방전율에 대하여 수행하였고, 충전실험은 $25^{\circ}C$에서 정전류-정전압 방법으로(제한전류 30A, 제한전압 14.24 V) 수행하였다. 모델에 근거하여 예측된 충 방전 거동은 충 방전 실험결과와 잘 일치하였다. 또한 2차원 모델링을 통하여 충 방전이 진행되는 동안 실제로 측정이 불가능한 납축전지 내부의 전류밀도, 전해액의 농도 및 충전상태(state of charge; SOC)의 분포를 예측할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.994-995
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• 2008

It is possible to suppress voltage drops, power loading fluctuations and regeneration power lapses for DC railway systems by applying an energy storage system. A electric double layer capacitor (EDLC) of the rapid charge/discharge type has been developed and used in wide ranges. It has a long life, high efficiency and maintenance free/low pollution features as a new energy storage element. In this paper, an efficient charge and discharge control method of a bidirectional DC-DC converter using the supercapacitor is proposed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.934-937
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• 1998

Charge/discharge property of LiMn2O4 was investigated with LiMn2O4/Li cell for use of lithium ion battery in electric vehicle. LiMn2O4 calcined at $800^{\circ}C$ for 36hr show high charge/discharge capacity and excellent cycle stability than that of others. This is found to be in agreement with expectation in the X-ray diffraction analysis. In addition, the kind and volume of conductive agent involved in LiMn2O4 cathode is excellent at super-s-black and 20wt%, respectively.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.97-99
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• 2008

It is possible to suppress voltage drops, power loading fluctuations and regeneration power lapses for DC railway systems by applying an energy storage system. Recently the electric double layer capacitor (EDLC) of the rapid charge/discharge type has been developed and used in wide ranges. The on board energy storage system with supercapacitor for railway vehicles presented in this paper seems to be a reliable technical solution with an enormous energy saving potential. In this paper, an efficient charge and discharge control method of a bidirectional DC-DC converter using the supercapacitor is proposed.

• 한국산학기술학회논문지
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• 제10권2호
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• pp.230-236
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• 2009

본 논문에서는 신재생 에너지 활용을 위한 그늘막 형태의 연계 계통형 태양광 발전 시스템을 제안한다. 제안하는 발전 시스템은 성하기에 해수욕장을 찾는 피서객들에게 상용전원과 연계 계통하여 최대 전력 수요를 충족시킬 뿐 만 아니라 그늘막으로서의 기능을 갖도록 설계하였다. 태양전지에서 생성된 전기를 낮 시간 동안 축전지에 충전하면 이를 야간에 전등이나 선풍기등에 이용할 수 있다. 축전지를 충전할 때 축전지의 성능을 유지하려면 충방전컨트롤러가 필요하다. 제안하는 축전지 충방전 컨트롤러는 고성능 마이크로프로세서를 사용하여 정확하고 안정된 동작을 하도록 설계하였고 사용자의 편의를 위해 디지털 표시기 및 축전지 교체시기 경보장치등을 갖추고 있다. 제안하는 발전 시스템을 영동 지역 해수욕장에 설치하고 실험을 통하여 전력 생산능력과 발전 성능을 확인하였다.

• 한국소음진동공학회논문집
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• 제21권11호
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• pp.997-1004
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• 2011

A fault detection algorithm of a charge and discharge system to ensure the safe use of hybrid electric vehicle is proposed in this paper. This algorithm can be used as a complementary way to existing fault detection technique for a charge and discharge system. The proposed algorithm uses a SVDD technique, which additionally utilizes two methods for learning a large amount of data; one is to incrementally learn a large amount of data, the other one is to remove the data that does not affect the next learning using a new data reduction technique. Removal of data is selected by using lines connecting support vectors. In the proposed method, the data processing speed is drastically improved and the storage space used is remarkably reduced than the conventional methods using the SVDD technique only. A battery data and speed data of a commercial hybrid electrical vehicle are utilized in this study. A fault boundary is produced via SVDD techniques using the input and output in normal operation of the system without using mathematical modeling. A fault detection simulation is performed using both an artificial fault data and the obtained fault boundary via SVDD techniques. In the fault detection simulation, fault detection time via proposed algorithm is compared with that of the peak-peak method. Also the proposed algorithm is revealed to detect fault in the region where conventional peak-peak method is never able to do.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.144-148
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• 1997

We synthesized polyaniline films electrochemically under constant current conditions, which exhibited electric conductivity as high as 100 S/cm. By charge and discharge cycling of polyaniline films, we obtained specific discharge capacity as high as 195 mAH/g using HSO$_4$- doped polyaniline. For the polyaniline synthesized using H$_2$SO$_4$ and HClO$_4$ composite electrolyte. we also obtained specific discharge capacity as high as 134 mAHg which rivals inorganic electro- active materials.