• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2121-2123
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• 2003

Distributed Control Systems(DCS) arc used in a wide range of process applications such as power plants. This paper presents calculated network capacity of a DCS that developed for nuclear power plant. The network hierarchies are 3 layed of information network, control network and field network. The assumed total node number of maximum DCS network is 64. Worst case network utilization of the DCS is simulated and analyzed.

• 조명전기설비학회논문지
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• 제30권2호
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• pp.78-84
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• 2016

This paper is focused on the measurement and analysis of an atmospheric electric field which is caused by thunderclouds. The electric field due to thunderclouds changes very slowly. For this reason, the extremely low frequency E-field sensor needs to be used for measuring the atmospheric electric field strength. The balloon-carried E-field sensor system with the time constant of 1sec was designed and fabricated. The electric field sensor consists of $100mm{\times}100mm$ copper plate, active integrator, high pass and low pass filters and batteries. The measurements of atmospheric electric fields were made by the balloon-carried E-field sensor and radiosonde, which sends the data back to ground in real time. From the calibration experiments, the response sensitivity of the E-field sensor was 0.154mV/kV/m in the frequency range of less than 1kHz. As a result from the actual experiment of the atmospheric electric field, the electric field signals were observed from the altitude of about 2.5km. Also, as the altitude was increased, the detected electric field wave oscillated with the fluctuation of sensing plate. The proposed method seems suitable for measurements of atmospheric electric fields, because it is inexpensive, simple to use and launch.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.191-194
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• 2014

The characteristics of laminar free jet flow with having applied AC electric fields have been investigated experimentally. A single electrode configuration was adopted such that electric fields were applied directly to nozzle and thus the surrounding could be an infinite ground. The experimental results showed that the jet flow with AC was modified significantly. At a certain axial distance, the laminar fuel stem was broken down and subsequently it was separated into three parts when AC electric fields were applied over a certain voltage in a range of frequencies less than 120 Hz. The breakdown point was measured by varying applied AC voltage and frequency. The effect of applying electric fields to jet flow was discussed in detail.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.318-319
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• 2011

Many countries are concentrating on the development of electric vehicle technology with increasing concerns about the global environment. Along with these concerns, plug-in hybrid electric vehicles(PHEVs) are being developed as environment-friendly cars which reduce greenhouse gas emissions and also eliminate the problem of range anxiety associated to all-electric vehicles, because the combustion engine works as a backup when the batteries are depleted. In this paper, electric equipments of the PHEV which meet the target specifications were developed, and their performance was proven through confirmatory testing on the PHEV at Korea Automotive Technology Institute(KATECH).

• 제어로봇시스템학회논문지
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• 제18권6호
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• pp.519-525
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• 2012

Electric brake booster systems replace conventional pneumatic brake boosters with electric motors and rotary-todisplacement mechanisms including ECU (Electronic Control Unit). Electric booster brake systems require precise target pressure tracking and control robustness because vehicle brake systems operate properly given the large range of loading and temperature, actuator saturation, load-dependent friction. Also for the implement of imbedded control system, the controller should be selected considering the limited memory size and the cycle time problem of real brake ECU. In this study, based on these requirements, a sliding mode controller has been chosen and applied considering both model uncertainty and external disturbance. A mathematical model for the electric booster is derived and simulated. The developed sliding mode controller considering chattering problem has been compared with a conventional cascade PID controller. The effectiveness of the controller is demonstrated in some braking cases.

• KEPCO Journal on Electric Power and Energy
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• 제3권2호
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• pp.119-125
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• 2017

Regarding the implementation of ROMM project (Rehabilitation, Operation, Maintenance & Management), which is one of overseas development projects, it is very important to diagnose the exact current status of aged thermal power plant. However, when people visit the power plant for the purpose of prediagnosis to implement the ROMM project, most target power plants for diagnosis, in general, are under operation. This can be a big interference factor to diagnose the exact current status of power plants. Therefore, in order to solve such interference factor, based on the 30 years of know-how in the field, the present study has developed a regression curve for a simple life time assessment and the calculation of rehabilitation cost that may be used as a reference relatively for the quantitative diagnosis on the status of a relevant power plant even during the operation of the power plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.149-151
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• 2009

Hybrid electric vehicle has three operating mode, depending on the operation of the engine and electric motor. According to the speed range of BLDC motor, In hybrid traction mode, both the engine and electric motor deliver to drive train. Battery charge mode, the electric motor operates as generator and is driven by the engine to charge the batteries. In engine alone traction mode, the electric motor is do-energized, and vehicle is propelled by the engine alone. we propose hysteresis current control technique to maintain constant speed in the motor load torque at the reverse direction. The proposed method is verified by using Matlab Simulink software.

• 전력전자학회논문지
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• 제27권1호
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• pp.74-79
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• 2022

This paper proposes a DC-DC converter that satisfies a wide output voltage of 150 V-1000 V for the battery voltage of various electric vehicles and can be controlled in both directions for the demand resource of electric vehicles. The proposed converter is a two-stage structure in which an insulated converter and a non-isolated converter are combined and operates as constant current or constant power depending on the voltage of the connected battery. Experimental results from a 20 kW prototype are provided to validate the proposed charger, and a maximum efficiency of 97% is obtained.

• 한국분무공학회지
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• 제28권1호
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• pp.24-31
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• 2023

In this study, characteristics of a propane-air premixed flame sin DC electric field was investigated. The stainless steel Bunsen burner and the stainless steel ring were used as electrode, and the high voltage supply was used for applying electric field. Flammability range increased significantly when the positive voltage was applied because of extension of LBO limit, while it shrank when the negative voltage was applied. The reason for this was not much related to the burning velocity, but the induced flow around the burner by electric field. withNOx production slightly increased after positive voltage was applied in identical equivalence ratio. Nevertheless, it was advantageous to apply the positive electric field to reduce the NOx since the extension of LBO limit makes the burner possible to operate in very low equivalence ratio.

• 한국산학기술학회논문지
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• 제12권3호
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• pp.1117-1121
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• 2011

전차에 전기를 공급하는 장치인 가동 브래킷 구조물은 전차가 통과할 때 반복적인 하중을 받는다. 이러한 반복하중은 가동 브래킷 구조물을 구성하는 나사들을 풀리게 하는 가진원이 되고 있다. 본 논문에서는 전산 시뮬레이션을 이용하여 반복적인 진동에 의한 볼트 풀림에 대한 원인과 대책에 대하여 연구하였다. 그 결과 전산 시뮬레이션 모델이 구축되어 가동브래킷 구조물의 동적응답 해석이 가능하게 되었다. 가동 브래킷 구조물의 볼트 풀림에 대한 주된 가진 주파수 영역이 200 Hz 미만임을 확인하였으며, H 빔의 강성을 증가함으로써 볼트풀림을 방지할 수 있음을 알 수 있었다. 아울러 볼트 풀림 원인이 되는 300, 600Hz 대역에서 발생하는 하부밴드 브라킷의 진동 모드를 확인 하였으며, 강성을 올리는 것은 200Hz 이상에서의 볼트 풀림을 방지할 수 있는 효과를 나타냄을 확인하였다.