• Journal of Power Electronics
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• 제6권3호
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• pp.195-204
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• 2006

This paper presents a new compensating system, consisting of series and shunt active filters, for mitigating voltage and current disturbances. The shunt filter is used to compensate for unbalanced and distorted load currents. The series filter comprises two inverters, used to suppress voltage disturbances and handle source currents independently. This configuration is devised to reduce the overall cost of active compensators by using low-frequency high-current switches for the latter inverter. The filters are controlled separately using a novel control strategy. Since voltages at the point of common coupling contain interharmonics, conventional methods cannot be used for extracting voltage references. Therefore, voltage references are obtained from generated sinusoidal waveforms by a phase-locked loop. Current references are detected based on rotating frame vector mapping. Simulation results are presented to verify the system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.82-84
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• 2004

This paper has calculated DSM's latent capacity through a survey investigating electric arc furnaces in over 2,000 toe companies and related organizations. The latent capacity of DSM calculated with the same time load factor is considered in this paper. The time load factor depends on the probability of each electric arc furnace of the value to work and the consideration of experts and technician's experience. Also, this paper verifies the reliability and application of unposed capacity which compared the old latent capacity of Load Management with KEMCO and KEPCO's Direct Load Control gathering capacity.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.946-948
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• 2006

It is important to keep a constant transmittance of dielectric during firing. To control the shrinkage and fusion stage of frits in firing, we used a hot stage microscope (HSM) to analyze the thermal properties of the lead and bismate glass frits by the in-situ method. This research would be useful for improving the reliability of transmittance of dielectric during firing in industry using a large furnace with temperature deviation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.98-100
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• 1989

In this paper, computer control system is introduce for the reheating furnace in the hot rolling process, and in order to support computer control system and process operation, the configuration of expert system application is demonstrated breefly, which is under fine tuning.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2507-2509
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• 2002

본 논문에서는 유리 용해로의 온도 제어를 위한 동역학 행렬 제어 (Dynamic Matrix Control, DMC) 기법의 적용 사례를 소개한다. 다양한 제약조건들과 긴 시간지연 응답을 갖는 유리 용해로는 DMC외 좋은 적용 분야가 될 수 있다. 먼저 용해로 테스트를 통하여 입출력 데이터를 생성하고 이를 바탕으로 용해로의 동역학 행렬 모델을 결정한다. 그 후, 모의 실험을 통하여 제어기의 설계변수들을 결정한다. 마지막으로, 제시된 제어기를 실제 용해로 생산 공정에 적용된 결과를 제시한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2590-2592
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• 2000

본 논문에서는 TV 브라운관 유리용해로의 온도 제어를 위한 고전 고급 제어 (Conventional Advanced Control) 알고리듬을 제시한다. 용해로의 특성에 맞도록 중요한 입출력 변수를 선정한 후, 공정 실험을 통하여 얻어진 데이터를 바탕으로 입출력 변수들간의 초보적인 FOPDT (First Order Plus Dead Time) 모델들의 조합으로 용해로를 모델링하였다. 수립된 모델을 바탕으로 주요 입출력을 PI (Proportional - Integral) 형태의 cascade 및 단일 궤환 루프(Single feedback loop)들의 조합으로 제어기를 구성하였다. 제시된 알고리듬은 기존 용해로에 설치되어 있는 DCS를 이용하여 구현되었고, 일 150톤 생산 규모의 용해로에 성공적으로 실적용되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3259-3263
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• 2007

This paper describes the proceedings of creating countermeasures after analysis and maintenance be able to conduct operation safely in a power plant. in order to operate the power plant in a stable and reliable way, the best condition of the govemor system can be maintained through the response characteristic analysis of the control device for the pitch blade control hydraulic actuator. The fan pitch blade control hydraulic actuator of a 500MW large-scale boiler is frequently operated under normal operation conditions. Common problems or malfunctions of the pitch blade control hydraulic actuators leads to the decline of boiler thermal efficiency and unexpected power plant trip. The inlet and outlet gas can be controlled by using the fan pitch blade control hydraulic actuator in order to regulate the internal pressure of the furnace and control the frequency in the power plant facility which utilizes soft coals as a power source.

• Journal of Advanced Marine Engineering and Technology
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• 제18권1호
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• pp.114-122
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• 1994

A cold temperature control system for the BAF(batch annealing furnace) has been established in order to reduce energy consumption to imrpove productivity and stabilize the properties of products. Therefore we confirmed a relation between annealing cycle time and atmospheric gas, changing annealing cycle time according to BAF temperature with time during heating and actual temperature measurements cold spot during soaking. The results of the temperature variation effect on the batch annealing are as follows. 1) Cooling rate is increasing gradually with increasing atmospheric gas flow, but heating rate is hardly increasing without atmospheric gas component. Heating time is reduced to one half with increasing atmospheric gas flow rate and changing of atmospheric gas component from HNx to Ax gas and annealing cycle time is reduce to 2.7 times. 2) With enlarging the difference between furnace temperature and soaking temperature at the HNx BAF, heating time becomes short, but cooling time is indifferent. 3) If temperature difference of 300.deg. C in the temperature change of cold spot according to the annealing cycle control temperature, Hi-CON/H2BAF is interchanging at each other at 26hours, but HNxBAF at 50 hours. 4) Soaking time at batch annealing cycle determination is made a decision by the input coil width, and soaking time for quality homogenization of 1219 mm width coil must be 2.5 hours longer then that of 914mm width coil for the same coil weight at Hi-CON/H2BAF. But, it is necessary to make 2 hours longer at HNxBAF.

• 콘크리트학회논문집
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• 제17권4호
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• pp.613-620
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• 2005

순환골재를 구조체용 콘크리트에 이용하는 것은 품질관리 및 내구성에 대한 논란으로 활성화가 현실적으로 어려운 실정이다. 이 경우 상대적으로 요구되는 품질 수준이 낮은 콘크리트 2차 제품에 순환골재를 활용하는 것이 유력한 대안이 될 수 있지만 증기 양생시 순환골재 콘크리트의 특성에 대한 연구성과는 거의 없는 실정이다. 이에 본 연구에서는 순환골재의 콘크리트 2차 제품 적용성을 검토하기 위하여, 다양한 순환 굵은골재 및 순환 잔골재 치환율에 따라 증기양생 및 수중양생을 통하여 제작된 콘크리트의 압축강도, 휨강도, 쪼갬인장강도, 부착강도 실험을 실시하였다. 강도 실험결과 순환 굵은골재의 치환율이 증가함에 따라 강도가 약간 감소하는 결과를 보이고 있으며, 순환 잔골재를 $100\%$ 치환한 경우에는 증기양생 콘크리트의 강도특성 저하가 뚜렷이 나타났다. 순환 굵은골재의 치환율이 $50\%$인 경우에는 압축강도, 휨강도, 부착강도가 보통 콘크리트와 거의 같게 나타나 일반 콘크리트와 동일하게 적용할 수 있을 것으로 판단된다. 순환골재와 고로슬래그 시멘트를 사용한 증기양생 콘크리트의 경우 증기양생 후 7일 시점에서 증기양생 보통포틀랜드 시멘트 콘크리트에 비해 강도가 낮게 나타났다. 양생방법에 따른 순환골재 콘크리트의 역학적인 차이는 일반 콘크리트와 유사하게 나타나 실제 2차제품의 생산에 순환골재 적용이 가능한 것으로 나타났지만 최적의 치환율을 결정하기 위해서는 추가적인 연구가 필요한 것으로 판단된다.

• 유공압시스템학회논문집
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• 제4권2호
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• pp.28-33
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• 2007

In the power plant facility which use soft coal as a power source the fan pitch blade control hydraulic actuator is used to control the inlet and outlet gas to regulate the internal pressure of the furnace and control the frequence. Sometimes malfunctions of this equipment lead to the decline of boiler thermal efficiency and unexpected power plant trip. In order to localize the fan pitch blade control hydraulic actuator specially for the 500MW large scale boiler, Analysis and modelling of the system is carried out mathematically. The responses of the system are examined by using matlab simulation fur the variation of the major parameters in view of reverse engineering. Consequently the validity of the established parameters are examined.