• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.67-71
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• 2015

The concept known as Vehicle-to-Grid (V2G) is to provide power to help balance loads by charging at night when demand is low and sending power to the grid when demand is high. Therefore, it is important to model the cost-benefit characteristics of Electric vehicle(EV)'s operation considering the negawatt market in real time. This paper proposes a methodology to formulate the various costs and economic benefits for sending the EV's power back to the grid, including a concept of inconvenience costs caused by operating the EV as a battery. This paper also introduces the general decision-making process based on the cost-benefit analysis in order to simulate the reasonable participation of V2G service. In the case study, it is confirmed by two-case simulations that the proposed approach is useful to help EV owners' decision-making. In the future, it is expected that the proposed methodology can be used as a decision-making guideline to help prepare the EV' power transmission.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1454-1470
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• 2014

This paper propose a new power conditioner topology with intelligent power management controller that integrates multiple renewable energy sources such as solar energy, wind energy and fuel cell energy with battery backup to make best use of their operating characteristics and obtain better reliability than that could be obtained by single renewable energy based power supply. The proposed embedded controller is programmed for maintaining a constant voltage at PCC, maximum power point tracking for solar PV panel and WTG and power flow control by regulating the reference currents of the controller on instantaneous basis based on the power delivered by the sources and load demand. Instantaneous variation in reference currents of the controller enhances the controller response as it accommodates the effect of continuously varying solar insolation and wind speed in the power management. The power conditioner uses a battery bank with embedded controller based online SOC estimation and battery charging system to suitably sink or source the input power based on the load demand. The simulation results of the proposed power management system for a standalone solar/WTG/fuel cell fed hybrid power supply with real time solar radiation and wind velocity data collected from solar centre, KEC for a sporadically varying load demand is presented in this paper and the results are encouraging in reliability and stability perspective.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.21-29
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• 2003

Boosting of engine power by using Turbo- or Super-charger is a solution to comply with $CO_2$-regulation in Europe. Turbo-charger is now playing a major role in the field of charging system thank to its technical advantages such as no demand of operation power from engine. A mechanically driven Super-charger, however, is now popular due to quick speed response to change of the driving mode-high engine torque even at low engine speed. Since Super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of Turbo-charger. This negative point is still an obstacle to the wide use of Super-charger. This study aims to develop power control concept to achieve the minimization of operation power when it is not necessary to charge at idling or part load driving condition. A screw type Super-charger was modified in design partially and adapted an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of Super-charger and result in improvement of fuel consumption.

• 전기학회논문지
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• 제67권11호
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• pp.1401-1407
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• 2018

This paper proposed a method of energy storage system (ESS) operation to increase acceptable production of renewable energy (RE). We analyzed the rebound effect that does not show a demand increase even if the capacity of the ESS is increased and considered the charging time by analyzing the time when the output limit is most generated. The rebound effect was mitigated by adjusting the discharging time of the ESS, and the effect of the increase of acceptable production of the renewable energy was analyzed by adjusting the charging time.

• 교육시설
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• 제15권5호
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• pp.21-32
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• 2008

The major issues that higher education has recently faced are the shortage of students of school age, the changing environment of higher education and the evolving technology. These challenges have urged the university facilities and space to be managing more efficient and more effective. This study assures that the strong strategy is to operate more like business while retaining unique higher education values and a sound facilities management system and appropriate budget help to ensure that university facilities are good for student and teacher's demand. With such faith, this study explores the facilities/space maintaining status and the facility management system of national universities and collages. It finds that there are some problems to adapt new managing methodologies in national universities and that there are also some gaps and perceived constraints to effective space management. This study proposes the alternatives for the facilities managing system that involves the improvement of manpower structure, the expansion of budget scale and the establishment of appropriate facility management system. Finally it provides the practical tools for the effective space and facilities management such as space charging, space standards, central timetabling, space utilisation survey and facilities performance indication.

• 한국산업융합학회 논문집
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• 제20권2호
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• pp.97-104
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• 2017

In the present industrial field, the demand for the development of the solar power source device and the charging device for the solar cell is gradually increasing. The solar charger is largely divided into a DC-DC converter that converts the voltage generated from the sunlight to a charging voltage, and a battery and a charger that are charged with an actual battery. The conventional charger topology is used either as a Buck converter or a Boost converter alone, which has the disadvantage that the battery can not always be charged to the desired maximum power as input and output conditions change. Although studies using a topology capable of boosting and stepping have been carried out, Buck-Boost converters or Sepic converters with relatively low efficiency have been used. In this paper, we propose a new Buck Boost combination power converter topology structure that can use Buck converter and Boost converter at the same time to improve inductor current ripple and power converter efficiency caused by wide voltage control range like solar charger.

• 전기전자학회논문지
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• 제23권2호
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• pp.747-750
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• 2019

웨어러블 디바이스는 일상생활에서 실질적으로 필수적이며 사용자들에게 편리하게 이용되고 건강관리와 의학 분야 등에 활용되고 있다. 전력분야에서 전원 배터리의 사용시간의 한계를 극복하고 효율적인 충전방법에 관한 많은 연구가 진행되고 있다. 무선전력전송은 전선을 사용하지 않고 무선으로 전기장을 부하에 전력을 전달하는 기술이다. 이 전송기술은 저 전력의 스마트폰에서부터 고 전력을 사용하는 철도 충전시스템까지 응용분야가 다양하다. 충전방식은 유도방법과 자기공진방법의 2 종류로 나누는데 자기공진주파수는 13.45 Mhz를 사용하였다. 본 연구에서는 전송효율을 측정 비교하기 위하여 2 종류의 하드웨어를 구현한 후 비교하는데 있다.

• 화약ㆍ발파
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• 제39권2호
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• pp.27-36
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• 2021

최근 노후화와 기능적 요건을 만족하지 못하여 불용하는 철골구조물의 해체 수요가 증가하면서 철골구조물 해체에 대한 관심이 부각되고 있다. 본 시공사례는 구조적 노후화와 기능적 요건을 만족하지 못하는 철골구조물인 ore bin과 coke bin 해체에 발파해체공법 중 전도공법을 적용하였으며, 철골구조물을 발파 절단하기 위해 장약용기를 사용하였다. 발파해체 결과, ore bin과 coke bin은 예측된 방향으로 정확히 전도되었으며, 주변 시설물에 피해 없이 발파해체를 완료하였다.

• 화약ㆍ발파
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• 제40권3호
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• pp.66-76
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• 2022

최근 오래된 산업단지의 해체수요가 증가하고 있으며, 해체된 산업부지를 원래 자연환경으로 복원하는 공사를 진행하고 있다. 본 시공사례는 오래된 산업단지 내의 대형 철골구조물을 해체하기 위해 발파해체공법 중 전도공법을 적용하였다. 철골구조물을 절단하기 위해 금속 제트가 발생하는 장약용기를 사용하였다. 발파구간 중 철골구조물의 두께가 두꺼운 부분은 가스와 산소 불꽃 또는 아크열에 의해 깊은 홈을 파는 방법인 가우징을 적용하여 두께를 조절하였다. 발파해체 결과, 철골구조물은 예측된 방향으로 정확히 전도하였으며, 주변 시설물에 피해 없이 발파해체를 완료하였다.

• 전기학회논문지P
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• 제63권1호
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• pp.40-45
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• 2014

This study examines the system and process of battery stored energy in vehicles and suggest the effective area for the use of V2G(vehicle-to-grid) from Jeju Smart Grid Demonstration Project. V2G means technology of electric power transmission from the battery of electric-drive vehicles to state grid. As for the increasing of effectiveness for demand-side control, V2G is a very good alternative. In the U.S., the utilization of electric vehicles is under 40% on average. In this case, we can use he battery of electric vehicle as role of frequency regulation or generator of demand-side resource. V2G, which is the element of Smart Transportation, consists of electric vehicle battery, BMS(battery management system), OBC(on-board charger), charging infrastructure, NOC(network operating center) and TOC(total operation center). V2G application has been tested for frequency regulation to secure the economical efficiency in the United States. In this case, the battery cycle life is not verified its disadvantage. On the other hand, Demand Response is required by low c-rate of battery in electric vehicle and It can be small impact on the battery cycle life. This paper concludes business area of demand response is more useful than frequency regulation in V2G application of electric vehicles in Korea. This provides the opportunity to create a new business for power grid administrator with VPP(virtual power plant).