• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2392-2396
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• 2011

This paper deals with the power integration of large urban railway systems to improve regenerative energy utilization. Current regenerative energy utilization is low because there is no special plan for using this energy. If the railway system is integrated with other railway systems, the efficiency is expected to be improved. Through the case studies, to find the realistic effect of integrated operation, real system for the Seoul Metro lines, especially line 5 and 7, had been applied.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.85-96
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• 2010

The recent environmental protection trend requires more strict energy saving, therefore every transportation system should reduce energy consumption to the minimum value. High-efficiency operation system, energy saving and $CO_2$ emissions shall be addressed as important issues in railway system. These issues are the most essential factors of railway, compared to major public transportation system. Recently, saving energy in the electric railway system has been studied. The efficient use of regenerated energy is considered to save energy. Namely, Using regenerative energy is that to store the energy generated during braking and discharge it again when a vehicle accelerates. Reusing energy stores and discharges energy, consequently enables a complete exchange of energy between vehicles, even if they are not braking and accelerating at precisely the same time, as is most frequently the case in everyday service. This paper analyzes effects of energy saving and $CO_2$-cut by using regenerative energy of electric vehicles.

• Journal of Drive and Control
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• v.9 no.4
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• pp.8-13
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• 2012

Recently, researches about the eco-friendly vehicles such as hybrid electric vehicle, fuel cell vehicle and electric vehicle have been actively carried out. The regenerative braking system is a key technology to improve the vehicle energy utilization efficiency because it transforms the kinetic energy to the electric energy through the electric motor. This new braking system requires cooperative control between electric controlled brake and regenerative brake. Therefore, it is necessary to establish fault-diagnosis and fail-safe evaluation criteria to secure reliability of the regenerative braking system. In this paper, the failure types and causes in regenerative braking system were analyzed. The transient behavior characteristics were examined based on fault-diagnosis and fail-safe upon failure of regenerative braking system.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.212-214
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• 2007

Regenerative energy which is generated during brake periods of DC traction might cause malfunction or destruction of rectifier or any other power conversion devices caused the increment of DC line voltage. Regenerative energy storage system using super-capacitor is one of the method to control the DC line voltage safely. And super-capacitor is very important device as energy storage device. Therefore, In this paper, we designed the regenerative energy storage system using super-capacitor and propose the method about predicting the lifetime of super-capacitor established in storage system. According to the this research, we can estimate the proper replacement moment for the existed super-capacitor due to the safety of the system. And improve the reliability of regenerative energy storage system using super-capacitor.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.7
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• pp.591-597
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• 2012

For the past few years, the concern for clean energy has been greatly increased. Ocean thermal Energy Conversion(OTEC) power plants are studied as a viable option for the supply of clean energy. In this study, we examined the thermodynamic performance of the OTEC power system for the production of electric power. Computer simulation programs were developed under the same condition and various working fluids for closed Rankine cycle, regenerative cycle, Kalina cycle, open cycle, and hybrid cycle. The results show that the regenerative cycle showed the best system efficiency. And then we examined the thermodynamic performance of regenerative cycle OTEC power system using the condenser effluent from Uljin nuclear power plant instead of the surface water. The highest system efficiency of the condition was 4.55% and the highest net power was 181 MW.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1505-1510
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• 2007

In this paper, the power simulation is used for the prediction of regenerative energy and examination of install location of regenerative inverter for DC railway system. The power simulation was composed to train performance simulation(TPS) and power flow simulation. We performed the power simulation for Seoul subway line 5 and 7, calculation of regenerative energy and examination of substations where regenerative inverter is installed.

• Journal of the Korean Ceramic Society
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• v.36 no.5
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• pp.497-503
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• 1999

Recently regenerative burner system was developed and begins to be gradually used for better energy savings. Compared to conventional burner system the regenrative one has the several merits such as higher fuel efficiency light weigh of apparatus low harmful toxic gas and homogeneous heating zone etc. The regenerative material a very important component of the new regenerative burner system should possess the properties of low specific density higher surface area and high specific heat capacity. Ceramics is the best regenerative material because of stable mechanical properties even at high temperature and better thermal properties and excellent chemical stability. In this study alumina ball alumina tube 3-D ceramic foam and hoeycomb as regenerative materials were tested and evaluated. The computer silumation was conducted and compared to the result of field test. This paper is aimed to introduce a new application of ceramics at high temperature.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.4
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• pp.137-146
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• 2000

The hydraulic energy regnerative brake systems is introduced in this work. An accumulator stores kinetic energy during braking action, and the stored energy is used in a following acceleration action. The dynamic model of the brake system is derived for computer simulation study, and the Runge-Kutta numerical integration method is applied to the simulation work. Since the model contains several unknown parameters, these were determined by data which had been proceeded. Through a series of computer simulation , dynamic performance of the energy regenerative brake system is compared with that of a conventional system in which a conventional brake circuit is used. A series of test is carried out in the laboratory. The dynamic characteristics of the hydraulic motor system, such as the surge pressure and response time, are investigated in both brake action and acceleration action.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1965-1977
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• 2018

This paper proposed a regenerative braking system (RBS) strategy for battery electric vehicles (BEVs) with a hybrid energy storage system (HESS) driven by a brushless DC (BLDC) motor. In the regenerative braking mode of BEV, the BLDC motor works as a generator. Consequently, the DC-link voltage is boosted and regenerative braking energy is transferred to a battery and/or ultracapacitor (UC) using a suitable switching pattern of the three-phase inverter. The energy stored in the HESS through reverse current flow can be exploited to improve acceleration and maintain the batteries from frequent deep discharging during high power mode. In addition, the artificial neural network (ANN)-based RBS control mechanism was utilized to optimize the switching scheme of the vehicular breaking force distribution. Furthermore, constant torque braking can be regulated using a PI controller. Different simulation and experiments were implemented and carried out to verify the performance of the proposed RBS strategy. The UC/battery RBS also contributed to improved vehicle acceleration and extended range BEVs.