• 전력전자학회논문지
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• 제22권4호
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• pp.336-344
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• 2017

This paper presents the three-port DC-DC converter modeling and controller design procedure, which is part of the solid-state transformer (SST) to interface medium voltage AC grid to bipolar DC distribution network. Due to the high primary side DC link voltage, the proposed converter employs the three-level neutral point clamped (NPC) topology at the primary side and 2-two level half bridge circuits for each DC distribution network. For the proposed converter particular structure, this paper conducts modeling the three winding transformer and the power transfer between each port. A decoupling method is adopted to simplify the power transfer model. The voltage controller design procedure is presented. In addition, the output current sharing controller is employed for current balancing between the parallel-connected secondary output ports. The proposed circuit and controller performance are verified by experimental results using a 30 kW prototype SST system.

• 한국분무공학회지
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• 제27권1호
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• pp.11-17
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• 2022

In upcoming Post Stage-V and Tier 5 regulations of construction machineries, nitrogen oxide (NOx) emissions are strictly limited in cold start conditions. In response to this, a method of improving NOx conversion efficiency has been applied by installing an electric heating catalyst (EHC) in front of conventional urea-SCR systems so that the evaporation and thermal decomposition of urea-water solution can be promoted in cold start conditions. In this strategy, the evaporation and thermal decomposition of urea-water solution and corresponding NOx conversion efficiency are governed by temperature conditions inside the EHC. Therefore, characterizing the temperature distribution in the EHC under various operating conditions is crucial for the optimized operation and control of the EHC in Urea-SCR systems. In this study, a 1-D modeling analysis was performed to predict the heater surface temperature distribution in EHC under various operating conditions. The reliability of prediction results was verified by comparing them with measurement results obtained using an infrared (IR) camera. Based on 1-D analysis results, the effects of various EHC operation parameters on the heater surface temperature distribution were analyzed and discussed.

• 조명전기설비학회논문지
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• 제19권8호
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• pp.70-76
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• 2005

본 논문은 분산전원이 연계된 배전계통의 신뢰도를 평가할 수 있는 해석적 기법과 그에 맞는 분산전원의 모델을 제시한다. 분산전원은 송전계통에 연계된 대규모 발전기와는 다른 운영방식을 가지기 때문에 기존의 기법과는 다른 해석기법과 모델을 필요로 한다. 제시되는 신뢰도 해석기법은 Monte-Carlo 시뮬레이션에 비해 간단하면서도 피크부하를 사용하는 해석기법에 비해 정확하기 위해 Load Duration Curve를 사용하였고, 최종적으로는 사례연구를 통해 제시된 기법의 정확성을 입증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.369-371
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• 2004

With the proliferation of nonlinear loads, high neutral harmonic currents in three-phase four-wire distribution system have been observed. It has been. known that the ground impedance has an effect on the neutral currents of a system which operates with harmonics present. On-site measurements of harmonic currents and voltages according to the fell-of-potential method under case study system were made and the ground impedance modeling using the pattern search method for the harmonic analysis was developed. The ground impedance model obtained by the proposed method was compared with the frequency characteristics by field tests and has shown appropriate results, and would be applicable to evaluate the harmonic and transient response characteristics of the ground system.

• 전기학회논문지
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• 제58권6호
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• pp.1065-1070
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• 2009

This paper presents the new technique of modeling using Dynamic Link Library(DLL) in ElectroMagnetic Transients Program - Restructured Version(EMTP-RV) in which we have simplified the procedures of OverCurrent Relay(OCR) modeling. The DLL function is designed to allow EMTP-RV users to develop advanced program model modules and interface them directly and intimately with the EMTP-RV engine. The modeled OCR is verified by simulating the various fault cases in the distribution system. Also, the performance for the modeling of OCR using DLL is compared with that of the method using the control components of EMTP-RV and using EMTP/MODELS. The results show the validity of modeled OCR and the effectiveness of the method using DLL function.

• 한국기계기술학회지
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• 제20권6호
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• pp.803-808
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• 2018

Combining digital automation solutions throughout recent manufacturing process is essential. Advanced robot and mechanical techniques are required for design, manufacture, and distribution process. Manual design of repetitive similar mechanical components during the development phase of these advanced machines and robots can occur wasting time and money. Developed gear design module, which is the power transfer system mechanical component, was programmed in the Visual Basic language in CATIA V5 environment. Automation Process is Based on Parametric Modeling Method. and it was found to be effective in reducing design time compared to designers manual modeling.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.181-183
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• 2002

Complete load model of the substation not only should include the performances of the load components, but also should take into consideration the core losses of transformers, the line losses and the capacitor banks. In an actual distribution system, the control scheme of capacitor banks are so complex and is difficult to identify actual values for the reactive powers of capacitor banks. This research improves on this drawback by applying component-based modeling method including a capacitor banks in distribution systems. Initial differences between the model results and the actual values for reactive powers are later decreased by the proposed method.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.395-398
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• 2011

This paper introduces stochastic cash-flow modeling integrated with simulation based scheduling. The system makes use of CPM schedule data exported from commercial scheduling software, computes the best fit probability distribution functions (PDFs) of historical activity durations, assigns the PDFs identified to respective activities, simulates the schedule network, computes the deterministic and stochastic project cash-flows, plots the corresponding cash flow diagrams, and estimates the best fit PDFs of overdraft and net profit of a project. It analyzes the effect of different distributions of activity durations on the distribution of overdrafts and net profits, and improves reliability compared to deterministic cash flow analysis.

• 한국시스템다이내믹스연구
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• 제7권1호
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• pp.213-228
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• 2006

This paper reports the results of a study designed to understand and facilitate disaster mitigation for communities located in low frequency/high magnitude earthquake zones. The study is based on a small town located near the New Madrid Fault Zone and is therefore at significant earthquake risk. A system dynamics model describes the variables and policies governing the distribution of building safety over time. Data from this town is used to establish a 25-year baseline. Simulations are run to demonstrate the consequences of different building policies.

• 유통과학연구
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• 제22권1호
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• pp.61-67
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• 2024

Purpose: The study has identified factors affecting dynamic capabilities and the distribution of competitive advantage under the impact of dynamic capabilities of Vietnamese fintech businesses. Research design, data, and methods: The method used in this study is a survey analysis of 120 Vietnamese fintech businesses to test the hypothesized relationships of the research model as well as evaluate its effectiveness. The study uses the Cronbach alpha analysis, factor analyses, and structural equation modeling to assess the research's measurement and structural models. Results: Research results show that 3 critical success factors: "Capacity to develop financial service ideas," "Ability to develop a platform," and "Business capacity" have a positive impact on "Dynamic capabilities." In addition, the study also evaluates the effect of "dynamic capabilities" on the "competitive advantage" of fintech businesses. Conclusion: Theoretically, this result contributes to discovering new, specific factors affecting the dynamic capabilities of fintech businesses. In practice, the research results are empirical evidence of the distribution of competitive advantages of Vietnamese Fintech businesses and their impact on dynamic capabilities.