• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.547-554
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• 2016

Analyze the customer daily load patterns, be used to determine the optimal charging and discharging schedule which can minimize the electrical charges through the battery energy storage system(BESS) installed in consumers is an object of this paper. BESS, which analyzes the load characteristics of customer and reduce the peak load, is essential for optimal charging and discharging scheduling to save electricity charges. This thesis proposes optimal charging and discharging scheduling method, using particle swarm optimization (PSO) and penalty function method, of BESS for reducing energy charge. Since PSO is a global optimization algorithm, best charging and discharging scheduling can be found effectively. In addition, penalty function method was combined with PSO in order to handle many constraint conditions. After analysing the load patterns of target BESS, PSO based on penalty function method was applied to get optimal charging and discharging schedule.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.253-261
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• 1999

It is essential for port planning, coastal zone management and environmental impact study to analyze the variation of current and water quality due to the development of water area and discharged water from the estuary barrage and basin, etc. Mokpo sea area has downstream from a long river and two large basins, the Yongsan river and Yongam-Kumho basins, discharging much of water through water gates for the purpose of flood and prohibition of salt intrusion to the inland fresh water area. In this study, the numerical calculation were carried out for the analysis of diffusion characteristics due to discharging operation, adopting the results of tidal current simulation. ADI method is applied to the governing equation for the movement of sea water and diffusion and 6-point method to the advection terms of diffusion equation. As the results of this study, it is known that the discharging operation causes increasing and/or decreasing of current velocity and enlarging and/or depressing of pollutant diffusion limits depending on the distance from the discharging gates and the modes of discharging operation. To utilize these result, the linked gate operation and the method increasing exchange of sea water must be considered.

• Transactions on Electrical and Electronic Materials
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• v.8 no.2
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• pp.97-102
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• 2007

The charging/discharging characteristics of electric double layer capacitors (EDLCs) for an electric power storage device application were investigated. The specific area of the carbonaceous electrode surface by the BET method was in the range of $1800{\sim}2000\;m^2/g$. The charge distributions during charging and discharging were measured by means of a pulsed-electro-acoustic (PEA) method, and the voltage characteristics of EDLCs connected to solar cells were evaluated. The results showed that the distributions of positive and negative charges were spatially uneven, which was due to the mobility of the positive and negative charges in the carbonaceous electrode surface of the EDLCs. The charge accumulation region concentrated on central part of the carbonaceous electrode and the required times for charging and discharging were almost same.

• Journal of Korean Port Research
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• v.13 no.2
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• pp.419-426
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• 1999

It is essential for port planning, coastal zone management and environmental impact study to analyze the variation of current and water quality due to the development of water area and discharged water from estuary barrage and basin etc. Mokpo sea area downstreams from a long river and two large basins, the Yongsan river and Yongam-Kumho basins discharging much of water through water gates for the purpose of flood control and prohibition of salt intrusion to the inland fresh water area. In this study, the numerical calculations were carried out for the analysis of diffusion characteristics due to discharging operation, adapting the results of tidal current simulation ADI methord is applied to the governing equation for the movement of sea water and diffusion and 6-point method to the advection terms of diffusion equation. As the results of this study, it is known that the discharging operation causes increasing and/or decreasing of current velocity and enlarging and/or depressing of pollutant diffusion limits depending on the distance from the discharging gates and the mode of discharging operation. To utilize these result, the linked gate operation and the method increasing exchange of sea water must be considered.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.4
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• pp.383-390
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• 2014

This paper deals with novel soft-switching method for a bidirectional DC-DC converter in battery charging and discharging system. The proposed soft-switching method provides ZVS and ZCS at turn-on, and ZVS at turn-off of the switch in both charging and discharging operation modes. The soft switching condition can be obtained in wide load range, and provide low switching loss as well as low voltage spike at turn-off of the switch. Proposed method is analyzed in charging and discharging mode. Simulation and experimental results validate the usefulness of the proposed soft-switching method.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2187-2189
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• 2001

The proposed algorithm has produced the rules of relationship between the load voltage, current, discharging electric power and ampere-hours, electric power capacity of battery on the basis of the data. Which were acquired through the battery discharging experiment that is defined by the battery's ambient temperature and various load conditions. Especially, by calculating the parameter of second order polynomial equation relation between the remaining capacity and the electric power, the algorithm is proposed adapting for the discharging pattern. And as the depth of discharging is increasing, the calculation-method of electric power is applied to decrease the accumulated error in the calculation method of capacity accumulation. Also, the proposed algorithm has compensated the temperature considering the capacity change of battery to the temperature.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.281-286
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• 2022

In this study, design of an intuitive internal resistance diagnostic device is to diagnose the residual capacity and aging of the battery regardless of the model and the internal protocol of the waste battery through the method of measuring the internal resistance of a waste battery. In this paper, charging and discharging were continuously performed with 2A charging and 5A discharging in order to secure data on impedance changes that may occur in the charging and discharging process of various methods. As a result of the final experiment, it was confirmed that the impedance change occurred during charging and discharging, and the amount of change increased as the charging/discharging C-rate increased. In addition, it was confirmed that the waste battery aged or abnormal cell had a large change in the impedance value.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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• pp.36-42
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• 2018

UNECE/WP29/GRPE/EVE has recently defined that the power of a hybrid electric vehicle is the system power. Although a method for measuring the maximum power of a hybrid electric vehicle is presented by KATRI, it does not consider charging and discharging characteristics of traction batteries. This study provides a maximum power measurement method which reflects the charging and discharging characteristics of traction batteries in NOVC-HEVs (Not Off Vehicle Charging-Hybrid Electric Vehicles). Both methods are compared with regard to the output measurement results.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.125-131
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• 1995

Pneumatic System has been mainly used as main equipment for actuation and control of fluid force in manufacturing industry. For velocity control of piston, meter-out restriction method is used in many cases. In this systems, meter-out restriction method is adopted for analysing the Dynamic Charging and Discharging Process which is Variable Volume Chamber. Experiments has been conducted for different supply pressure condition. As a experimental result, charge side chamber pressure rises to supply pressure rapidily and discharge side chamber pressure decreases. Also, when the air in the cylinder is discharged, tempdrature of air decreases steeply. Restriction of the Cylinder sometimes freeze and it dose not function. The result will be useful for the analysis of pneumatic system.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.17-23
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• 2004

In the present work, the numerical model was refined to predict the thermal analysis of energy storage in a fixed beds during (charging ,storing, discharging) mode. The governing energy equations of both fluid and the solid particles along with their initial and boundary conditions are derived using a two-phase, one dimensional model. The refined model is carried out by taking into account change of (air density , air specific heat) with air temperature and also by taking into considerations heat losses from bed to surrounding. Finite difference method was used to obtain solution of two governing energy equations of both fluid and solid particles through a computer program especially constructed for this purpose. The temperature field for the air and the solid are obtained, also efficiency of energy stored inside the bed is computed. Finally using refined model the effect of air flow rate per unit area Ga (0.2, 0.3, and 0.4 kg/$m^2$-s), and inlet air temperature (200, 250, 300 $^{\circ}C$) on energy storage characteristics was studied in three mode ( charging ,storing, discharging). The rock particles of diameter 1 em is used as bed material in this research.