• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.831-833
• /
• 2001

Line-start motor has ability to start itself without using other methods, so, it is important to predict starting performance accurately. In this paper, the starting characteristics of single-phase capacitor-start, capacitor-run line-start motor was calculated by combination of d-q axis voltage equations and mechanical dynamic equations. D-q axis inductances of this machine varied with current phase angle and amplitude are considered. The validity of analysis method verified by comparing to test results.

• 전자통신동향분석
• /
• 제24권5호
• /
• pp.52-61
• /
• 2009

교토 의정서에 의한 지구 온난화의 규제 및 방지를 위하여 자동차에 환경 관련 규제가 강화되고 있으나 재생에너지가 전체 에너지에서 차지하는 부분은 2020년에 약 1%(현재는 약 0.4%) 정도로 예측되어 대체에너지 개발 이전에 에너지 저감 기술에 대한 필요성이 대두되어 차량의 공회전 상태시 엔진 구동을 정지시키는 Stop-Start 시스템에 대한 연구가 자동차 제조사 중심으로 연구되어 왔으며 불필요한 공회전으로 소모되는 연료 손실 중 $5{\sim}8%$ 이상 회수 가능함이 입증되고 있다. 본 고에서는 Stop-Start 시스템 기술에 대하여 소개하고, 국/내외 시장동향을 분석하여 그 필요성에 대하여 고찰하며, 한국전자통신연구원에서 개발중인 IT 융합 Stop-Start 시스템 개발 현황에 대하여 기술한 후 결론을 맺는다.

• 한국지열·수열에너지학회논문집
• /
• 제14권1호
• /
• pp.16-21
• /
• 2018

This work aims to develop a platform to investigate the effect of operation schedules on the building energy consumption and to derive a simulation model based optimal start and stop daily strategy. An open-source building energy simulation tool DOE2 is used for the engine, and the developed simulation model is validated using ASHRAE guideline 14. The effect of late-start/early-stop operation of HVAC system on the daily building energy consumption was analyzed using the developed simulation model. It was found that about 10% of energy consumption cut was possible using the control strategy for an hour of advance of the stop operation, and about 3% per an hour of delay of the start operation.

• 전기학회논문지
• /
• 제65권1호
• /
• pp.103-107
• /
• 2016

In general, the voltage stability of induction generator is lower than synchronous generator. Induction generator has a number of advantages over the synchronous generator on the side of price and maintenance. So Induction generator has been applied to the small hydroelectric power of low output. Induction generator usually generates a high current during grid connection. The high current that occurs during grid connection can cause a voltage drop in the system. In order to increase the supply of the induction generator, it is necessary to propose a method of reducing high current. This paper proposes some method of the soft start to reduce voltage drop caused by the large starting current. soft-start method has high voltage drop effect than direct start method, control of firing angle can be increased the voltage drop effect.

• 전자공학회논문지B
• /
• 제30B권2호
• /
• pp.87-96
• /
• 1993

Because of the complexity, nonlinearity and long-time delay of power plant, the star-up operation of a fossil power plant is very difficult to automate. So the start-up operation is always carried out by the skilled human operators, who utilize their knowledges and experiences for the predesigned start-up schedules and procedures. In this paper, a fuzzy logic controller is designed for the start-up operation of the power plant. And the operators experiences are modeled in terms of fuzzy sets and variables. To validate the controller, a drum-type boiler of the Seoul Power Plant is constructed via the signal flow diagram. Using the model, the suggested automatic start-up operation is verified, and the results are also presented.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집B
• /
• pp.662-667
• /
• 2000

A simulation procedure for a full transient analysis of the start-up of heavy-duty gas turbines for power generation is constructed. Compressor stages are grouped into three categories (front, mid, rear) and three different stage characteristic curves are applied to consider the different low-speed operating characteristics. Start-up behavior of a typical single-shaft gas turbine for power generation is simulated. The predicted transient behavior shows a good agreement with the field data. Special attention is paid to the effects of the modulation of VIGV on start-up characteristics, which play a key role in the stable operation of gas turbines.

• 지식경영연구
• /
• 제21권2호
• /
• pp.41-58
• /
• 2020

A plan to promote public technology-based start-ups as a way to enhance the use of public technology has been emphasized. However, the problem of creating commercial value has persisted due to the lack of reproducibility and readiness of public technology. Although gap exists in the linking process between the public and private sector, it is difficult to find objective empirical evidence as most of them are only qualitative research. Our empirical works examine the impact of subsequent support of the public research institute on the commercialization of public technologies. Then, we analyze how commercialization of public technologies affects the growth of technology-based startups using 2-stage least square (2SLS) model. We find that the linkage with the technology subject contribute to the successful commercialization of public technology, and further to the survival and growth of technology-based start-ups. Our finding suggests that knowledge management system, to facilitate interaction between technology developer and consumers, is needed for the success of public technology-based start-ups.

• 전력전자학회논문지
• /
• 제19권6호
• /
• pp.557-563
• /
• 2014

This study deals with a resonant converter of an anti-start air conditioner compressor for commercial vehicles. The anti-start air conditioner compressor must generally have a high current, high efficiency, a low volume, and a low weight. To reduce the switching losses and voltage and current stresses of the device, the anti-start air conditioner compressor applies the full-bridge L-C resonant converter topology. Hardware parameters are designed to have a wide voltage range, and the switching frequency range of the L-C resonant converter is determined. Simulation is implemented using PSIM and an experiment is performed to verify the proposed converter.

• 동력기계공학회지
• /
• 제13권3호
• /
• pp.47-52
• /
• 2009

The effect of forging start temperature, forging ratio on the microstructure and mechanical properties of B7B4 steel ware investigated. Microstructure of centrifugal casted B7B4 steel consisted of martensite and ferrite phase. The volume fraction of ferrite increased with increase of forging start temperature and decreased with increase of forging ratio. Tensile strength and hardness decreased with higher of forging start temperature, while impact value and elongation increased with higher of forging start temperature. With increase of forging ratio, tensile strength rapidly increased up to the forging ratio of 30%, and then slowly increased, but elongation was decreased. Hardness and impact value rapidly increased with increase of forging ratio.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 추계학술대회 논문집
• /
• pp.17-20
• /
• 2008

Cold start of a fuel cell system is a major obstacle should be overcome as to commercialize it, especially for passenger vehicle applications. However, the cold start characteristics is so complicated since it involves various phenomenon such as ice-blocking in GDL, ionic conductivity in membrane affected by water activity with phase change, heat transfer through components such as bipolarplates or endplates, electro-chemical reactions affected by circumferential temperature and humidity as well. Axiomatic design provides a systematic method to investigate the complex phenomenon although it was developed as a methodology to establish logical design procedure by Nam P. Suh in 1990s. This paper presents a framework to approach the complex cold start problem using Axiomatic Design which features simplifying a problem through hierarchical decomposition and decoupling from the view of functional requirements and design parameters.