• 정보통신설비학회논문지
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• 제2권1호
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• pp.37-44
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• 2003

In this paper, a technique to estimate EMI source distribution on a digital circuit board ir introduced. A sensitivity analysis method is applied to reconstruct the source distribution from measured electric field data. Results from a single-layer measurement and a double-layer measurement are compared. It will be shown, from the simulation, that the use of sensitivity analysis for the EMI source reconstruction problem can be a very promising technique.

• Journal of information and communication convergence engineering
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• 제6권4호
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• pp.417-420
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• 2008

Solar electric systems have very little impact on environment, making them one of the cleanest power-generating technologies available. While they are operating, PV systems produce no air pollution, hazardous waste, or noise, and they require no transportable fuels. In PV system design, the selection and proper installation of appropriately-sized components directly affect system reliability, lifetime, and initial cost. In this research, we have studied the PWM(Pulse Width Modulation) signals. I proposed an efficient photovoltaic power interface circuit incorporated with a DC-DC converter and a sine-pwm control method full-bridge inverter. In grid-connected solar power systems, the DC-DC converter operates at high switching frequency to make the output current a sine wave, whereas the full-bridge inverter operates at low switching frequency which is determined by the ac frequency. Thus, it can reduce the switching losses incurred by the full-bridge inverter. Full-bridge converter is controlled by using microprocessor control method, and its operation is verified through computer aided simulations.

• 전기학회논문지
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• 제65권11호
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• pp.1913-1918
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• 2016

In order to analyze the power consumption pattern of the DC urban rail system, the method to obtain a solution establishing the current equation according to fixed position of the substation and varying position of the train is used. The proposed analysis method using the network analysis is to model the transfer function of the component constituting a direct current power supply system (dc substation, train, catenary) to the voltage and current. By multiplying the model formula consecutive, it can calculate the voltage and current of each element of power supply circuit and shows a simple case analysis.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2002년도 하계학술대회 및 세미나
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• pp.6-9
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• 2002

In this paper a technique to estimate EMI source distribution on a digital circuit board is introduced. A sensitivity analysis method is applied to reconstruct the source distribution from measured electric field data. Results from a single-layer measurement and a double-layer measurement are compared. It will be shown, from the simulation, that the use of sensitivity analysis for the EMI source reconstruction problem can be a very promising technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1593-1594
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• 2015

본 논문에서는 진공 차단기의 투입 시 발생하는 고주파 재발호 진동현상을 모의하여 계통의 전압-주파수 특성을 분석한다. 우선 시간영역에서 차단기 투입에 따른 개폐 서지 현상을 모의하여 다중 재발호에 의한 진행파의 주파수 특성을 검토한다. 모의 결과를 통해 추정된 고주파 회로저항과 기존 전원, 고압케이블, 변압기로 구성된 고주파 재발호 진동해석용 등가 회로를 구현하고 주파수 스캔 기능을 이용하여 인가되는 전압의 주파수 변화에 따른 계통의 임피던스 크기변화를 확인한다. 끝으로, 시간 영역 및 주파수 영역에서 도출된 계통의 공진 주파수와 철도차량용 주 변압기의 공진주파수를 비교하여 내부 공진 여부에 따른 권선간 전압 확대 가능성을 논하고자 한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.237-240
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• 2002

A CCFL model for high frequency dimming electronic ballast simulation is presented in this paper. The model can be utilized for an electronic ballast simulation with continuous dimming and transient mode simulation such as step dimming. The piezoelectric transformer Is evaluated using an AC analysis. The electronic ballast composed of piezoelectric transformers and ZVS inverter was implemented. It enables a fluorescent lamp to be fumed on stably. Simulation of a high frequency electronic ballast which operates a fluorescent Imp at high frequency is proposed. Simulation is carried out using PSPICE program to illustrate the performance of the circuit

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.405-407
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• 2010

Simple equivalent circuit model is developed for wireless energy transfer system via coupled magnetic resonances and practical design method is also provided. Node equations for the resonance system are built with the method expanding transformer's equations and the optimum distances of coils in the system is derived analytically for optimum coupling coefficients for high transfer efficiency. Moreover, to calculate the frequency characteristics for a lossy system the equivalent model is established at an electric design automation tool. The model parameters of the actual system are extracted and the results of modeling are compared with the measurement. Through the developed model, we can understand the principles that the system shows higher efficiency than conventional magnetic coupling systems and impedance matching is important to achieve high efficiency.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.587-595
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• 1998

Transient thermal analysis simulations are carried out using a modeling program to understand the human body model HBM ESD. The devices were simulated a one-dimensional device subjected to ESD stress by solving Poison's equation, the continuity equation, and heat flow equation. A ramp rise with peak ESD voltage during rise time is applied to the device under test and then discharged exponentially through the device. LDD and NMOS structures were studied to evaluate ESD performance, snap back voltages, device heating. Junction heating results in the necessity for increased electron concentration in the space charge region to carry the current by the ESD HBM circuit. The doping profile adihacent to junction determines the amount of charge density and magnitude of the electric field, potential drop, and device heating. Shallow slopes of LDD tend to collect the negative charge and higher potential drops and device heating.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.456-457
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• 2007

ATCB의 구조 중 아크 소호부는 공기 중에 노출된 금속(그리드)이 일정한 간격을 두고 적층되어 있는 모양을 하고 있다. 아크 소호부의 주기능은 아크를 소호실 안쪽으로 유도하여(기중 차단방식) 여러 개의 짧은 아크로 분할시키며 아크를 냉각, 소멸시켜 전류 차단을 빠르게 하는 것이다. 아크를 구동시키는 소호살의 형상과 구조에 따라 아크의 구동력은 많은 차이를 보이게 된다. 여기서는 신개념의 자동절체 스위치인 ATCB(Automatic Transfer Circuit Breaker)의 그리드의 구조에 따라 아크 구동력을 비교하여 아크 소호부의 최적 형상과 절연구조를 설계, 모델링하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1940-1942
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• 2001

Magnetic Levitation System(MLS) levitates a steel ball to the desired position in the gravity field using electromagnetic force. MLS consists of light sensor to measure the position of steel ball and an electromagnet to control the position of the ball, that composes a feedback control system. This work does not use a steel ball with constant mass but variable mass steel balls as magnetic levitation targets. Differential equation of electric circuit for electromagnet and motion equation of the movement of steel ball are derived for modeling nonlinear system, that will be linearized at the nominal operating point. We propose a digital control that can levitate a steel ball of which weight is not known for ED-4810 system. Algorithm for estimating ball weight and feedback control are implemented in digital scheme under pentium PC equiped with A/D and D/A converter, ACL-8112, using C-language. Simulation and experimental results are given to show the usefulness of the proposed controller.