• Journal of Power Electronics
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• 제10권1호
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• pp.85-90
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• 2010

In this paper the effects of a Static Synchronous Series Compensator, which is constructed with a 48-pulse inverter, on the power demand from the grid are studied. Extensive simulation studies were carried out in the MATLAB simulation environment to observe the compensation achieved by the SSSC and its effects on the line voltage, line current, phase angle and real/reactive power. The designed device is simulated in a power system which is comprised of a three phase power source, a transmission line, line inductance and load. The system parameters such as line voltage, line current, reactive power Q and real power P transmissions are observed both when the SSSC is connected to and disconnected from the power system. The motivation for modeling a SSSC from a multi-pulse inverter is to enhance the voltage waveform of the device and this is observed in the total harmonic distortion (THD) analysis performed at the end of the paper. According to the results, the power flow and phase angle can be controlled successfully by the new device through voltage injection. Finally a THD analysis is performed to see the harmonics content. The effect on the quality of the line voltage and current is acceptable according to international standards.

• 한국전자파학회논문지
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• 제22권6호
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• pp.598-604
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• 2011

본 논문은 연결된 결합 선로를 이용하여 브랜치 선로 결합기를 소형화하는 방법을 제시하였다. 이 방법은 기존 마이크로스트립 브랜치 선로 결합기에 사용되는 ${\lambda}/4$ 선로를 같은 특성을 갖는 연결된 결합 선로로 대신한 방법이다. 연결된 결합 선로는 우-기 모드 해석 방법을 기반으로 Z 파라미터와 T 등가 회로로 분석하였다. 이 결과를 이용하여 연결된 결합 선로를 갖는 브랜치 선로 결합기를 중심 주파수 2.4 GHz에서 FR4 기판으로 설계하고 제작하였다. 실험 결과는 이론값과 잘 일치했다. 그리고 실험 결과, 기존 단일 마이크로스트립 선로로 구현된 결합기보다 37 % 크기가 줄어들었음을 확인할 수 있었다. 이 방법은 앞으로 이동 통신 빔 형성 안테나의 급전선인 Butler Matrix의 크기를 줄이는 방법으로 사용 가능하리라 사료된다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.443-450
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• 2017

Nowadays, Power Line Communication (PLC) is gaining high attention from industry and electric supply companies for the services like demand response, demand side management and Advanced Metering Infrastructure (AMI). The reliable services to consumers using PLC can be provided by utilizing an efficient PLC channel for which sophisticated channel modeling is very important. This paper presents characterization of a Low Voltage (LV) access network for Narrowband Power Line Communications (NB-PLC) using transmission line (TL) theory and a Simulink model. The TL theory analysis not only includes the constant parameters but frequency selectivity is also introduced in these parameters such as resistance, conductance and impedances. However, the proposed Simulink channel model offers an analysis and characterization of capacitive coupler, network impedance and channel transfer function for NB-PLC. Analysis of analytical and simulated results shows a close agreement of the channel transfer function. In the absence of a standardized NBPLC channel model, this research work can prove significant in improving the efficiency and accuracy of NB-PLC communication transceivers for Smart Grid communications.

• 전기학회논문지
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• 제56권6호
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• pp.1099-1104
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• 2007

A 1:6 Unequal 2-way Wilkinson power divider is proposed. The required microstrip line with $207{\Omega}$ characteristic impedance for 1:6 power divider is realized by adding defected ground structure (DGS) to the standard microstrip line. The adopted DGS has the rectangular geometry which results in the increased characteristic impedance. The rectangular-shaped DGS produces the transmission line having much higher characteristic impedance due to the increased equivalent inductance. The measured performances of the fabricated 1:6 power divider show the expected S-parameters with a good agreement with the predicted ones.

• Journal of electromagnetic engineering and science
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• 제14권4호
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• pp.415-418
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• 2014

This paper presents an equivalent circuit model for a dumbbell-shaped defected ground structure (DGS) in a microstrip line. The effects of equivalent circuit elements of a dumbbell-shaped DGS and their magnetic coupling to the host transmission line are modeled as a simple lumped-element circuit. In addition, simple approximate expressions to determine the main circuit parameters for this model are presented. The transfer characteristic calculated by the proposed circuit model is compared with the results of EM simulation and measurement.

• 한국항행학회논문지
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• 제21권1호
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• pp.84-89
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• 2017

본 논문은 CRLH (composite right/left handed) 전송선로 구조의 4중 모드 공진기를 이용하여 높은 대역간 격리도를 갖는 이중-광대역 대역통과 여파기를 설계하는 방법을 제안한다. CRLH 전송선로 구조를 해석하여 4중 모드 공진기의 s-패러미터와 공진 주파수를 유도하였다. 유도된 s-패러미터를 이용하여 새로운 구조의 이중-광대역 대역통과 여파기를 설계, 제작하였다. 측정 결과는 2.8-5.52 GHz, 9.68-12.26 GHz의 이중 통과대역에서 각각 1.08 dB, 2.01 dB의 삽입손실을 갖고, 6.34-8.42 GHz의 중간대역에서 38dB의 대역 격리도를 가져 설계 결과와 잘 일치하는 특성을 보여 주었다.

• 전자공학회논문지C
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• 제36C권3호
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• pp.26-34
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• 1999

실리콘 집적회로 인터컨넥트에서 전송선 파라미터를 추출하는 새로운 방법을 제시하고 이를 실험적으로 고찰 한다. 실리콘 기판 위에 있는 전송선에서의 신호는 PCB (printed circuit board)혹은 MCM (multi-chip module)의 인터컨넥트와 같은 마이크로 스트립 구조에서 가정하는 quasi-TEM 모드가 아니라 slow wave mode (SWM)로 대부분의 에너지가 전송되기 때문에 기판의 효과를 고려하여 전송선 파라미터를 추출한다. 실리콘 기판에서 전계 및 자계의 특성을 고려하여 커패시턴스 파라미터의 계산을 실리콘 표면을 그라운드로 설정하고 계산하고 인덕턴스는 단일 전송선 모델로부터 추출한 실효 유전상수를 도입하여 계산한다. 제안한 전송선 파라미터 추출 방법의 타당성을 검증하기 위하여 테스트 패턴을 제작하여 실험적 파리미터 추출 값이 제시한 방법의 결과와 약 10% 이내에서 일치한다는 것을 보여 계산 방법의 타당성을 입증한다. 또한 고속 샘플링 오실로스코프(TDR/TDT 메터) 측정을 통하여 제시한 방법이 크로스톡 노이즈를 정확히 예측 할 수 있는 반면 흔히 사용하고 있는 기판의 효과를 고려하지 않는 RC 모델 혹은 ？ 모델은 약 20∼25% 정도 과소 오차(underestimation error)를 보인다는 것을 보인다.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권2호
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• pp.107-111
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• 2003

In the power-line communication systems, there are many factors of noise and attenuation in the power-line channels, because they were designed for not the communication but the power transmission. Also the transfer function of the channels is highly changed with the topology and the load of the power-lines. To cope with these poor channel situation, channel modeling, one of the many studies in progress, is being studied hard. Channel modeling is essential to apply the active schemes to overcome the bad channel(e.g. modulation technique, channel coding, signal coupling & filtering, etc.) to the power-line communications. In this paper, we have realized the statistical model(this model is suggested as the channel modeling method for the power-line channels) that is combined the transfer function with the various noises. And we have compared and examined the results with the measured data. Also we have studied the plan which can effectively establish the channel data base for the channel information consisted of the parameters that are derived from this modeling, and we have studied the plan to utilize the data base.

• The Journal of the Acoustical Society of Korea
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• 제17권4E호
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• pp.35-40
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• 1998

In this paper, an efficient quantization method of line spectrum pairs(LSP) with cascaded structure of vector quantizer and scalar quantizer is proposed. First, input LSP parameters is vector-quantized using a codebook a with a moderate number of entries. In the second stage of quantization, the components of residual vector are individually quantized by the scalar quantizer. The utilization of ordering property of LSP parameters and the inclusion of interframe prediction improve the quantizer performance and remove the stability check routine after quantization procedure. The new vector-scalar hybrid quantizer using 26 bits/frame shows a transparent quality of speech that an average spectral distortion is 1 dB and the frame proportion with above 2 dB spectral distortion is less than 2%. The performances of proposed quantization method is evaluated in the transmission errors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.160-162
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• 2007

This paper presents a method to identify the equivalent circuit parameters by experiment results of supercapacitor model based on transmission line. In order to validate this method, a model of supercapacitor is verified and implemented by using the PSIM software. Experimental and simulation results are compared to verify the electric modeling of supercapacitors.