• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.5
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• pp.594-600
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• 2006

The optimization has been performed to search an economical running pattern in the view point of trip time and energy consumption. Fuzzy control model has been applied to build the meta-model. To identify the structure and its parameters of a fuzzy model, fuzzy c-means clustering method and differential evolutionary scheme ate utilized, respectively. As a result, two meta-models for trip time and energy consumption are constructed. The optimization to search an economical running pattern is achieved by differential evolutionary scheme. The result shows that the proposed methodology is very efficient and conveniently applicable to the operation of railway system.

• The KSFM Journal of Fluid Machinery
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• v.12 no.6
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• pp.41-46
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• 2009

This paper deals with the operating-speed (high-speed) balancing of a refinery gasoline HDS (hydrodesulfurization) process recycle-gas 8-stages compressor rotor. A low-speed balancing condition of the rotor was measured as maintaining the G2.5 level. But an inspection run of operating-speed balancing condition, using tilting-pad journal bearings of actual use, showed that while it could be continuously-operated safely at a rated speed of 10,500 rpm, the rotor would not be able to run over 11,000 rpm as the vibration increased very sharply, approaching 11,000 rpm. In order to cure that a series of operating-speed balancing, which first calculated balance correction-weights by applying the influence coefficient measured and calculated at 10,500 rpm and then implemented correction works, was carried-out. The final operating-speed balancing results showed that the vibrations at the bearing pedestals represented very good levels of 0.2 mm/s by decreasing to as much as the 1/10 of the original vibrations and particularly, even at a targeted maximum continuous operating speed, MCS, of 11,500 rpm the vibrations represented about 1 mm/s, which is the operating-speed balancing vibration specification of API. Therefore, the expansion of MCS was successfully accomplished through the operating-speed balancing.

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.307-312
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• 2020

Fluidized bed reactors operated in subatmospheric pressure has been focused because several industrial applications such as vacuum drying and plasma cvd requires reduced pressure fludization. However, the hydrodynamics of fluidized beds in subatmospheric pressure has not been extensively investigated. The pressure drop in the fluidized bed has been measured with variation of downstream pressures from 1.33 to 101.3 kPa in the shallow and deep fluidized beds under the sub-atmospheric pressures. The obtained minimum fluidization velocity of powders is a function of pressure due to the changes of gas density and mean free path. We can experimentally determine the critical Knudsen number and the critical pressure to define the slip regime significantly to influence the hydrodynamics of fluidized beds.

• The KSFM Journal of Fluid Machinery
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• v.10 no.2 s.41
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• pp.63-67
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• 2007

• The KSFM Journal of Fluid Machinery
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• v.10 no.2 s.41
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• pp.68-74
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• 2007

• 전기의세계
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• v.41 no.5
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• pp.35-46
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• 1992

우리나라는 300km/h에 달하는 속도의 고속전철을 도입할 단계에 있다. 이 시점에서 고속전철의 운전보안 시스템을 조사하고 철도기술의 선진국이라 할 수 있는 프랑스, 영국, 독일, 일본의 기술단계를 재조명해 봄으로써 도입될 전철에 대한 기술이전에 대한 바탕을 제공해 줄 수 있다는 점이다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.4
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• pp.32-37
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• 1999

본 논문에서는 위치센서 없는 Switched reluctance motor에 대해 저가로 구현가능한 새로운 속도제어 알고리즘을 제안한다. 대부분의 기존의 연구결과들은 상전환을 위한 점호각을 정확히 검출하는 것을 목표로 하였다. 그러나, 점호각 검출에서의 오차는 고속운전시 발생토크맥동과 효율의 저하, 심지어 탈조를 야기해왔다. 속도제어를 위해 제안하는 방법은 잘 알려진 phase locked servo(PLS) 속도제어루프에 ΔΣPLL과 유사한 점호각추정기를 위상검출기로 사용하는 것이다. 그것에 의하여, 제안한 알고리즘은 점호각검출오차와 발생토크맥동을 줄일 수 있다. 따라서, 저가로 고속운전에서의 속도오차를 감소시킬 수 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.59-62
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• 2010

로봇모터제어에 사용되는 서보전동기의 센서리스 운전에 대한 초기의 연구에서는 전동기의 전압과 전류를 측정하여 전동기 모델로부터 속도를 연산하는 방식을 취해왔으나, 근래에는 현대제어 이론 중 관측기 이론을 적용하여 속도 추정 및 센서리스 운전을 위한 다양한 연구가 시도되고 있다. 본 논문에서 설계한 슬라이딩형 퍼지 관측기의 속도추정 성능을 검증하기 위해 먼저 슬라이딩 관측기를 이용하여 전기자 전류의 도함수를 추정하고 속도관측기인 Luenberger 관측기의 이득을 퍼지 제어 기법을 이용하여 관측기 이득을 최적 값으로 선정하고 이것을 이용하여 직류 서보 전동기의 속도제어에 적용하였다.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.609-615
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• 2012

TPS (Train Performance Simulation) based on ATO (Automatic Train Operation) is required for driverless LRT (Light Rail Transit) operation plan instead of typical TPS based on driver operation. In this paper, new TPS model using ATO pattern is proposed and compared with the automatic train operation result in a test line of Seoul Metro Line 6 and in a whole line of Busan-Gimhae LRT. The actual ATO pattern can be very accurately simulated by new TPS model with the introduction of 4 parameters such as commercial braking rate, jerk, station stop profile and grade converted distance. The commercial scheduled time for driverless automatic train operation can be proposed to have "Fast" mode TPS trip time plus 3 seconds/km margin recommended by Korean standard LRT specification in this paper.

• Plant Journal
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• v.8 no.4
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• pp.34-39
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• 2012

This study presents how low quality coal combustion affects the desulfurizer draft system by correlating of draft loss in a coal-fired thermal power plant and predicts the stall occurrence time of a booster fan. In case of low quality coal, a lot of coal is needed to generate equivalent output power, thereby the rating of increasing draft loss was faster than designed amount of coal. We surely confirmed that draft loss affects the specific energy of a booster fan strongly. On this basis, it is possible to predict the occurring time of stall for a booster fan from current operation specific energy to stall limit specific energy. This study suggests increasing speed of draft loss in each caloric value and the impact of specific energy at a booster fan, it expects to help safe operating in a thermal power plant.