• 한국철도학회논문집
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• 제15권2호
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• pp.116-121
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• 2012

DC/DC스위칭 전력 컨버터는 임의의 직류전원을 부하가 요구하는 형태의 직류전원으로 변환시킨다. DC/DC 컨버터는 PWM-IC를 이용하여 주기적으로 입력측에서 출력측으로 전달되는 에너지를 제어하는 기능을 수행하는데, PWM-IC(펄스폭 변조-집적회로), MOSFET(산화물-반도체 전계 효과 트랜지스터), 인덕터, 콘덴서, 저항 등으로 구성되어 있다. 방사선의 영향으로 DC/DC 컨버터의 PWM-IC 를 구성하는 비교기(comparator)와 연산증폭기(OP-Amp.) 등 전자소자의 열화 효과(radiation effects)가 발생되는데, PWM-IC 동작에서 SPICE 시뮬레이션과 실험을 통해 펄스의 상실, 펄스폭의 변화, 그리고 출력파형의 변화를 연구하는데 있다.

• 한국철도학회논문집
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• 제20권1호
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• pp.31-42
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• 2017

철도 시스템의 전력 소비를 줄이기 위한 많은 연구가 진행되고 있다. 그 중에서 급속충전방식 무가선 전동차 시스템은 철도 분야에서 매우 효율적인 에너지 절감 기술로 주목 받고 있다. 본 논문에서는 ESS를 이용한 급속충전 무가선 전동차 시스템을 소개하고 현재의 도시철도 전기요금 산정방식에 대하여 분석하였다. 이러한 분석을 바탕으로 급속 충전 무가선 전동차 시스템 적용 가능한 두 가지 전기요금 저감 방안(기본요금을 저감하는 방식(Case 1)과 전력량요금을 저감시키는 방식(Case 2))을 제안하였다. 제한하는 방식의 타당성 확인을 위해 현재 운영 중인 전동차 시스템(도시철도 2호선)의 전기요금과 비교하여 비용 경제성을 평가하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.896-899
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• 2003

The electric railway has been widely used as a transportation all over the world. It also was opened in 1973 in korea and it has been steadily proceeded in making electric railway network for a big city and building Keongbu high speed , electric railway. That's why the system of electric railway is able to solve the environmental pollution and operate the useful energy in environmental ways, it helps to increase the ability of transportation and to decrease the cost. Because of the advantage of making the economic situation better, the system of electric railway is trying to do their best in developing technique of electric railway. Because of the increasing of transportation and the high speed operation, cars with regenerative braking system was adapted. Therefore, unbalanced voltage and current of three phase system and the drop and rise of voltage of feeding circuit is expected. Now that building the substation, newly spends lots of costs and time, it is a very difficult situation to solve the problem. We can guess that electric railway line can't receive power from the power system of bigger size in building newly electric railway. In this paper, it was proved that series voltage compensator was suitable as a solution according to voltage drop and voltage fluctuating through computer simulation.

• 전기학회논문지
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• 제65권12호
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• pp.2197-2210
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• 2016

Recently, the trend of zero emissions has increased in automotive engineering because of environmental problems and regulations. Therefore, the development of battery electric vehicles (EVs), hybrid/plug-in hybrid electric vehicles (HEVs/PHEVs), and fuel cell electric vehicles (FCEVs) has been mainstreamed. In particular, for light-duty electric vehicles, improvement in electric motor performance is directly linked to driving range and driving performance. In this paper, using an improved design for the interior permanent magnet synchronous motor (IPMSM), the EV driving range for the light-duty EV was extended. In the electromagnetic design process, a 2D finite element method (FEM) was used. Furthermore, to consider mechanical stress, ANSYS Workbench was adopted. To conduct a vehicle simulation, the vehicle was modeled to include an electric motor model, energy storage model, and regenerative braking. From these results, using the advanced vehicle simulator (ADVISOR) based on MATLAB Simulink, a vehicle simulation was performed, and the effects of the improved design were described.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.609-617
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• 2016

Belt-driven Starter Generator (BSG) differs from other mild hybrid systems as the crankshaft of vehicle are not run off. Motor permits a low-cost method of adding mild hybrid capabilities such as start-stop, power assist, and mild levels of regenerative braking. Wound rotor synchronous motor (WRSM) could be adopted in BSG system for HEV e-Assisted application instead of the interior permanent magnet synchronous motor (IPMSM). In practice, adequate torque is indispensable for starter assist system, and energy conversion should be taken into account for the HEV or EV as well. Particularly, flux weakening control is possible to realize by adjusting both direct axis components of current and field current in WRSM. Accordingly, this paper present an off-line current acquisition algorithm that can reasonably combine the stator and field current to acquire the maximum torque, meanwhile the energy conversion is taken into consideration by losses. Besides, on account of inductance influence by non-uniform air gap around rotor, nonlinear inductances and armature flux linkage against current variation are proposed to guarantee the results closer to reality. A computer-aided method for proposed algorithm are present and results are given in form of the Look-up table (LUT). The experiment shows the validity of algorithm.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.72-72
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• 2012

Lithium rechargeable batteries have been widely used as key power sources for portable devices for the last couple of decades. Their high energy density and power have allowed the proliferation of ever more complex portable devices such as cellular phones, laptops and PDA's. For larger scale applications, such as batteries in plug-in hybrid electric vehicles (PHEV) or power tools, higher standards of the battery, especially in term of the rate (power) capability and energy density, are required. In PHEV, the materials in the rechargeable battery must be able to charge and discharge (power capability) with sufficient speed to take advantage of regenerative braking and give the desirable power to accelerate the car. The driving mileage of the electric car is simply a function of the energy density of the batteries. Since the successful launch of recent Ni-MH (Nickel Metal Hydride)-based HEVs (Hybrid Electric Vehicles) in the market, there has been intense demand for the high power-capable Li battery with higher energy density and reduced cost to make HEV vehicles more efficient and reduce emissions. However, current Li rechargeable battery technology has to improve significantly to meet the requirements for HEV applications not to mention PHEV. In an effort to design and develop an advanced electrode material with high power and energy for Li rechargeable batteries, we approached to this in two different length scales - Atomic and Nano engineering of materials. In the atomic design of electrode materials, we have combined theoretical investigation using ab initio calculations with experimental realization. Based on fundamental understanding on Li diffusion, polaronic conduction, operating potential, electronic structure and atomic bonding nature of electrode materials by theoretical calculations, we could identify and define the problems of existing electrode materials, suggest possible strategy and experimentally improve the electrochemical property. This approach often leads to a design of completely new compounds with new crystal structures. In this seminar, I will talk about two examples of electrode material study under this approach; $LiNi_{0.5}Mn_{0.5}O_2$ based layered materials and olivine based multi-component systems. In the other scale of approach; nano engineering; the morphology of electrode materials are controlled in nano scales to explore new electrochemical properties arising from the limited length scales and nano scale electrode architecture. Power, energy and cycle stability are demonstrated to be sensitively affected by electrode architecture in nano scales. This part of story will be only given summarized in the talk.

• 한국철도학회논문집
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• 제14권2호
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• pp.167-173
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• 2011

본 연구는 전력소비완화를 위해 전동열차의 출발시간을 조정하는 문제를 다룬다. 전동열차의 운행은 역행, 타행 및 제동의 단계로 구성된다. 역행단계는 전동열차의 운행을 위해 많은 전력량이 필요로 하며, 타행단계는 그 전력을 바탕으로 전력 소비가 거의 없이 운행되는 단계이고, 마지막으로 제동단계는 정차를 위해 감속하는 단계로 전동열차의 관성력으로 인해 운동에너지가 전력으로 바뀌어 회생전력이 발생한다. 회생전력은 동일 전력계통의 운행구간에서 동 시간대에 역행운행 중인 전동열차의 동력자원으로 재사용 될 수 있어 소비전력량을 줄이는 것이 가능하다. 이를 위해 혼합정수계획모형을 제안하고 모형의 실효성을 검증하기 위해 수도권 도시철도 한 구간의 전력데이터를 사용하여 실험하였다.

• 한국산업융합학회 논문집
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• 제26권5호
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• pp.915-923
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• 2023

As environmental regulations on carbon emissions are strengthened worldwide, the existing internal combustion engine-centered automobile industry is being reformed. In particular, large buses and large cargo trucks are pointed out as one of the main causes of environmental destruction due to excessive carbon emissions. The E-Highway power collection system, which has recently been proposed as a solution, uses the vehicle's battery as a backup power source or regenerative braking, depending on whether the pan head of the pentograph installed in the vehicle is in contact with the overhead line. It is used to store the excess energy generated. However, wear through contact due to continuous contact reduces the current collection effect and causes failure. In this paper, by using the current difference, the horizontal position information of the panhead in contact with the overhead line is acquired, thereby reducing the abrasion of the conductor and the panhead Make it possible to follow the overhead line. The position estimation method proposed in this paper simply configures a device that can detect the position of the overhead line of the pantograph by the difference in resistance. It is economical and has the advantage of reducing the volume. The characteristics of the pantograph estimating the location of overhead lines were analyzed using the difference between the two currents of the current collector, the feasibility of the positioning estimation system was verified through simulations and experiments.