• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.412-413
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• 2010

Voltage Source Converter(VSC)는 입력전류와 전압을 동상의 정현파로 제어할 수 있고, 전압을 승압하여 일정한 DC전압을 만들 수 있으며, 양방향 제어가 가능하다. 본 논문은 3상 VSC를 동기회전좌표계로 변환하여 등가회로로 모델링하고, VSC의 제어기와 소신호 등가모델을 제시한다. 시뮬레이션을 통해 회로해석과 소신호 등가모델의 타당성을 검증하였고, 실험결과를 통하여 제어기를 설계의 타당성을 증명하였다.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.1
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• pp.9-16
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• 2003

To evaluate the seismic performance of multistory building structures use an equivalent SDOF model to represent the resistance of the structure to deformation as it respond in its predominant mode. This paper presents a method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through perform nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. The hysteresis rules to be used an equivalent SDOF model is obtained from the pushover analysis. Comparing the peak inelastic response of a moment resisting reinforced concrete frames and an equivalent SDOF model, the adequacy and the validity of the converting method is verified. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. The representative lateral displacement of a moment resisting reinforced concrete frames is close to the height of the first modal participation vector \ulcorner$_1{\beta}$${_1{\mu}}=1$. It can be found that the hysteresis rule of an equivalent SDOF model have influence on the time history response. Therefore, it necessary for selecting hysteresis rules to consider hysteresis characteristics of a moment resisting reinforced concrete frames.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.461-462
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• 2007

실시간 시뮬레이터(RTDS)를 이용한 비선형 전력 계통의 과도현상 해석은 H/W의 제약으로 인해 계통의 규모에 따라 그 적용범위가 제한되므로, 대규모 계통의 RTDS 모의를 위해서는 대상 계통의 축약된 등가 계통의 개발이 요구된다. 이에 본 연구에서는 한전 계통의 RTDS 적용 및 모의를 위해, 실 계통의 정적, 동적 특성을 반영할 수 있는 적정규모의 등가 계통 개발에 대한 연구를 진행하고, 등가화 및 계통 축약 기법을 이용해 240기 986모선 규모의 한전 계통에 대한 42기 143모선의 규모의 등가 모델 계통을 개발하였다. 등가 모델 계통은 경제성을 고려하여 실 계통의 동특성을 반영하는 최소 규모의 모델로 개발되었으며, PSS/E를 이용한 다양한 모의를 통해 실계통의 특성을 적절히 반영하는 것을 확인하고 타당성을 검증하였다. 또한 PSS/E로 구성된 모델 계통을 RSCAD를 이용해 변환하고, RTDS를 이용한 모의를 진행하는 것으로 그 특성을 확인하였다.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.3
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• pp.21-28
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• 2008

To evaluate the seismic performance of multi-degree of freedom(MDF) systems, repeated nonlinear response history analyses are often conducted, which require extensive computational efforts. To reduce the amount of computation required, equivalent single degree of freedom(SDF) systems representing complex multi-degree of freedom(MDF) systems have been developed. For the equivalent SDF systems, bilinear models and trilinear models have been most commonly used. In these models, the P-$\Delta$ effect due to gravity loads during earthquakes can be accounted for by assigning negative stiffness after elastic range. This study evaluates the adequacy of equivalent SDF systems having these hysteretic models to predict the actual response of steel moment resisting frames(SMRF). For this purpose, this study conducts cyclic pushover analysis, nonlinear time history analysis and incremental dynamic analysis(IDA) for SAC-Los Angeles 9-story buildings using nonlinear MDF models(exact) and equivalent SDF models(approximate). In addition, this study considers the strength limited model.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.376-377
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• 2011

본 논문에서는 LCL 필터를 사용한 계통 연계형 3-레벨 인버터의 소신호 등가모델을 유도하는 과정과 이 모델을 이용한 계통 전류 및 중성점 전류 제어기를 설계하는 내용을 소개한다. 소신호 등가모델은 평균화 과정, 변동과 선형화 과정을 통해 유도하였다. 특히, 중성점 전류 제어기 설계를 위한 DC 링크단의 소신호 모델은 새로운 스위칭 함수를 적용시킴으로써 유도하였다. 제안된 방식의 검증을 위하여 시뮬레이션을 실시하였고 또한, 소용량 프로토타입을 제작하여 실험 결과를 통해 본 논문에서 제안한 모델링 및 제어기설계의 타당성을 입증하였다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.194-195
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• 2011

본 논문은 Bi-directional Inverter(BDI)에 DQ 변환을 적용한 소신호 등가 모델과 이중 루프 제어기 설계에 대해 제안한다. 일반적으로 외부루프의 경우 동적 특성이 매우 느리기 때문에 외부루프 전달함수를 고려하지 않고 설계하는 경우가 많다. 결과적으로 시스템의 안정성이나 동적 특성이 설계한 것과 다르게 나타날 수 있다. 따라서 원하는 특성을 만족하기 위해 실험적 시행착오를 거쳐 설계를 하게 된다. 본 논문에서는 정확한 소신호 등가 모델을 제시하고 제어기를 설계한다. 제안된 방식은 PSIM 시뮬레이션 및 실험을 통해 회로해석과 소신호 등가모델의 타당성 및 제어기 설계의 타당성을 증명하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.3
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• pp.231-242
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• 2009

In the design of a sky-bridge, repetitive boundary nonlinear time history analyses are required to accurately predict dynamic behaviors of the connected buildings because the connection systems of a sky-bridge usually have high nonlinearity. If a conventional finite element model for entire high-rise buildings is used for repetitive boundary nonlinear time history analyses, computational efforts could be significant. In this study, an equivalent cantilever model considering the belt-wall effect has been proposed for an efficient dynamic analysis and a performance evaluation of vibration control of high-rise buildings connected by a sky-bridge. To verify the accuracy and efficiency of the proposed equivalent model, boundary nonlinear time history analyses of 49- and 42-story example buildings connected by a sky-bridge have been performed for wind excitation. Based on the analytical results, it has been verified that the proposed equivalent model can provide accurate dynamic responses of building structures connected by a sky-bridge with significantly reduced computational efforts.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.227-234
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• 2011

Recently, a high strength concrete of more than 40 MPa has been increasingly used in practice. However, use of the high strength concrete may influence on design parameters, particularly stress distribution. This is very true since the current everyday practice employs equivalent rectangular stress distribution that is derived from normal strength concrete. Subsequently, the stress distribution seems to be reevaluated and then a new distribution with new parameters needs to be suggested for the high strength concrete. For this purpose, linear and multiple regression analyses have been carried out in term of using experimental data for the high strength concrete of 40 to 80 MPa available in literatures. Accordingly, new parameters associated with the stress distribution have been proposed and employed for the design of flexural and compressive members. Comparative design examples indicate that designs with new parameters reduce section dimensions compared to those with the current code parameters for concrete strengths of 40 to 70 MPa. In particular, for compressive members, design with new parameters exhibit conservative compressive force compared to those with the current code parameters.

• Tunnel and Underground Space
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• v.17 no.3 s.68
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• pp.234-243
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• 2007

In this paper, it was aimed to enhance core processes required in establishing hydrogeological models constructed using borehole investigation results. Water Conducting Feature(WCF) information was extracted from borehole investigation, and HydroDFN model was constructed based on the WCF information. The HydroDFN model was sub-divided by cubic blocks, and equivalent permeability of each sub-divided block was calculated and compared with the results of hydraulic test at the borehole. Through these analysis processes, suggestion for identifying and prescribing WCF parameters in the construction of HydroDFN model was made.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.81-86
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• 2006

Routing signal lines in PCB, line shapes would be straight or bent. time-domain and frequency-domain evaluation of the signal property and interference are archived by precise Modeling of differential signal line. Some of CAD tools can extract equivalent circuit model parameters. but it takes a long time and heavy loads. This paper introduces a basic RLC equivalent circuit model parameter extraction technique for bent differential structures using genetic algorithm by this technique, we can model equivalent circuit of bent differential structures more faster.