• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.3
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• pp.20-28
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• 2007

The easiest way to see the phenomena of compressor surge is to show the static and dynamic operation characteristic on the map. Its operation zone will be restricted by the surge limit and, static and transient process must have some margin for it. Effect of rotor moment of inertia, air/gas volumes and heat transfer are factors to cause the transition from the static line. In case a large volume such as heat exchanger exists in the system it will exert a substantial influence to dynamic characteristics. In the present paper, influence of air volume bled from the compressor exit on transient process is investigated with an example of an auxiliary power unit micro-turbine engine. Turbine mass, pressure ratio, rotation speed, power and moment are calculated based on mass and work conservation. Result from the present study can give guidance to design the control system. A computer program is developed to calculate the dynamic process using the MathCAD commercial software.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.51-60
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• 2009

과도현상으로부터 보호되고 대응력을 갖출 수 있는 수신기가 될 수 있도록 과도현상 보호시스템을 설계 제작하고 적용성을 성능시험으로 입증하였다. 과도현상 보호시스템을 개발함으로서 수신기에 높은 신뢰성과 안정성을 부여할 수 있다. 과도현상 보호시스템의 개발을 위한 프로세스 정립과 이론을 바탕으로 과도현상으로부터 보호될 수 있는 1단계 및 2단계 보호시스템의 시작품을 제작하고, 소방법 및 관련규정에서 제시하는 제반 성능 조건으로 시험하고 만족스런 결과를 얻음으로써, 과도현상 보호시스템을 개발할 수 있는 엔지니어링 데이터 구축과 원천기술을 확립하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.753-763
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• 1989

The transient response of a three-dimensional straight fin of constant cross sectional area and perimeter with unequal top, bottom, left, right and tip surface convection coefficients is analyzed using separation variables and Laplace transforms when the fin base is subjected to a step change in temperature. The three-dimensional effects of fin dimensions and unequal fin surface convection coefficients on the fin performance which is expressed in terms of the heat flowrates through the fin base are investigated, and errors in one-dimensions and unequal fin surface coefficients. Typical results are represented in tabular and graphical forms.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.75-81
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• 2000

To provide the appropriate direction for development of transient control in a gasoline engine, transient performance analysis and evalution under four accelerating types based on typical driver's acceleration type were implemented by experimental study. In order to evaluate the characteristics of transient performance quanititatively, the concept and method by transient response specifications were introduced. Several performance parameters in terms of engine speed(RPM), manifold absolute pressure(MAP), fuel injection duration($\DeltatI_{nj}$) and air excess ratio($\lambda$) were emasured simultaneously during the four types of the throttle valve opening with the step motor controlled by PC. The result showed that transient response specifications in terms of delay time, rising time and settling time characterized the transient performance for four acceleration types quantitatively. Intensified acceleration type was most economical and linear acceleration type revealed the best emission performance.

• Fire Science and Engineering
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• v.23 no.2
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• pp.55-61
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• 2009

This study has been carried on the transient phenomenon protection system to become fire alarm system control unit of high reliance which can be protected from transient phenomena for surge or transient overvoltage, and constructed engineering base that can develop transient phenomenon protection system by proving performance of protection system in a experimental. This study developed 1 step and 2 step protection system that can be protected from transient phenomenon with process thesis and theory for development of transient phenomenon protection system. It established engineering data construction and a source technology that can develop transient phenomenon protection system as gets satisfied result and test with all performance condition that present in fire protection law and connection regulation.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.206-207
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• 2011

지금까지 영구자석 동기 전동기의 구동에 있어서 약자속에 대한 연구는 대부분 정상상태에서의 전류제어성능에 초점이 맞춰져 왔다. 그러나 전류 지령이 급변하는 상황에서는 신속하게 정상상태에 이르는 것이 중요함에도 불구하고, 이에 대한 연구는 많지 않았다. 본 논문에서는 약자속(Flux Weakening) 운전시 전류제어의 과도상태를 개선하여 정상상태에 빠르게 도달하도록 하는 약자속기법을 제안하였다. 제안된 방법은 정상상태의 전류 지령을 결정하는 약자속제어기와, 과도상태에서 전압 여유분을 확보하여 빠르게 정상상태에 이르도록 하는 과도 지령 수정기로 구성된다. 컴퓨터를 이용한 모의 실험과 11kW 영구자석 전동기에 대한 실험을 통하여 제안된 약자속기법의 성능을 확인하였다.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.9 no.3
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• pp.11-18
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• 2013

Small and medium-size buildings employ a multi-distributed individual air-conditioning system utilizing package air conditioners instead of centralized cooling systems, which can allow easier building management and maintenance along with a diversification of facility use. Inverter driven system heat pumps have been developed to achieve not only easy distribution control allowing free combination of indoor units with different models and different capacities, but also wide applications to an intelligent air conditioning. In this study, the transient performance of a system heat pump was analysed with the variation of compressor speed and EEV openings. The superheat was selected as a control parameter of the system, because the variation of it was consistent with each indoor unit capacity.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.11
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• pp.510-513
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• 2002

In this paper, the robust adaptive controller design scheme is studied for nonlinear systems in the presence of bounded disturbances A new robust adaptive controller is designed using high-order neural networks, which avoids the singularity problem in adaptive nonlinear control. The stability of the resulting adaptive system with the proposed adaptive controller si guaranteed by suitably choosing the design parameters and initial conditions. I addition, the proposed adaptive controller provides improved transient performance and fast on-line adaptation. The ability and effectiveness of the proposed adaptive control scheme is shown trough simulations of a simple nonlinear system.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.206-207
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• 2013

본 논문에서는 태양광 배터리 충전 시스템에서 충전 모드가 변환될 때 과도상태를 보상하기 위한 알고리즘을 제안한다. 제안하는 알고리즘은 기존의 정전류-정전압 충전 알고리즘을 기반으로 정전류 모드에서 정전압 모드로 변경될 때 과도상태를 보상하기 위한 최적의 제어기법을 추가함으로 기존 알고리즘보다 우수한 과도 특성을 갖는다. 본 논문은 3kW급 PSIM 시뮬레이션을 통해서 제안하는 충전제어 알고리즘의 우수한 제어특성을 검증하였다.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.165-165
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• 2012