• Nuclear Engineering and Technology
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• v.25 no.3
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• pp.371-380
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• 1993

A model free controller utilizing a set of linguistic fuzzy logic of the human operator's experience is developed to control the steam generator water level in a pressurized water reactor. Only 9 rules for control action are generated from the inputs of water level error and mass flow error implicitly representing the time variation of the collapsed water level. The bell type membership functions of the premise side and the result side are tuned by the sensitivity study. This compact fuzzy logic controller shows a robust control during transient and no offset error and oscillation during steady state operation. For a multi-ramp power increase from start-up to full power, the proposed controller shows good performance for the entire range.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.78-84
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• 1998

The fluid system such as, the quantity control of raw water, chemicals control in the purification, the waste water system as well as in the feed water or circulation system of the power plant and the ventilation system is controlled with the valve and moter pump. The system's performance and the energy saving of the fluid systems depend on control of method and delicacy. Until, PI controller use in these system but it cannot control delicately because of the coupling in the system loop. In this paper we configure a single flow system to the multi variable system and suggest the application of 2-DOF PID controller and the tuning methods by the neural network to the electrical power of the flow control system. the 2-DOF controller follows to a setpoint has a robustness against the disturbance in the results of simulation. Keywords Title, Intelligent control, Neuro control, Flow control, 2 - DOF control., 2 - DOF control.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.377-382
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• 1989

암모니아 합성을 위한 다단식급냉반응기를 대상으로 물질 및 에너지보존법칙을 적용하여 수식모델을 전개하였다. 실제 4단 반응기의 설계 및 운전자료를 기준으로 하여 정상상태의 다중성을 해석하고 각 촉매층의 체적비와 반응물의 공급유량비에 대한 최적화 연구를 수행한 결과 실제 조업조건하에서 3개의 서로 다른 정상상태가 존재하며 실제 설계 및 조업조건은 최적조건을 다소 완화한 조건에 상당한 것임을 확인하였다.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2152-2154
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• 2003

전력계통 및 발전기의 안정 운용을 위해 발전기 제어계의 정밀 제어와 정확한 계통 해석을 위한 발전기 관련 정밀 파라미터 취득 및 관리가 요구되는 상황에서 발전기 현장시험과 발전기 관련 안정도 해석용 데이터 취득이 필요한 실정임. 현장 시험(발전기 제어계 특성시험)을 통해서 취득한 데이터를 가지고 모델링 및 제어정수를 조정하여 전력계통 안정도 해석용 데이터 베이스를 구축하게 되는데, 여자기 형식에 따라서 계단 입력 신호가 주어졌을 때 시간응답 특성이 약간씩 차이가 나게 됨. 그리고 발전기 제어계 특성시험은 발전기 직접 관련 데이터 및 원동기(터빈) 입력신호(주증기 유량신호, 주증기 제어밸브 개도 등)까지 측정하게 되는데, 본 논문에서는 발전기 여자제어에 관련된 부분만을 살펴 보았음.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.444-444
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• 2018

하천의 수질개선을 위해서는 유역에서 배출되는 배출량을 제어하는 것뿐만 아니라 오염원별 기여도를 파악하고 효과적인 수질개선대책을 수립하는 것이 필요하다. 또한, 계절 및 유량조건에 따라 오염원의 배출량, 배출특성이 상이하게 나타나기 때문에 이를 고려하여 기여도를 파악하는 것이 필요하다. 본 연구에서는 청미천 유역을 대상으로 계절 및 유량조건에 따라 오염원별 기여율를 산정하고, 해당 유역의 수질개선을 위한 주요 인자를 도출하고자 한다. 기여율 분석을 위해 청미천 내에 유량 및 수질측정지점을 기준으로 소유역 구분을 하였으며, 소유역별로 물환경정보시스템을 통해 받은 유량 및 수질 자료를 활용하여 유량-부하량 관계곡선을 도출하였다. 유황조건별 부하량을 도출하기 위해 실측 유량 및 수질자료를 활용하여 유황곡선과 LDC(Load Duration Curve) 곡선을 작성하였다. 오염원별 기여도 산정을 위해 환경부의 2015년 전국오염원조사자료를 활용하여 소유역별 배출부하량을 산정하였으며, 앞서 산정한 LDC 곡선과의 비교를 통해 오염원별로 기여율을 산정하였다. 본 연구의 방법은 향후 유역의 수질개선대책 수립 시 오염원별 기여도 도출을 위한 기초자료로 활용될 수 있을 것으로 사료된다.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.12-16
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• 2007

Temperature control of an autothermal methanol reforming reactor which uses the copper-zinc oxide catalyst was studied. Temperature at 1cm below the hot-spot point in the reactor was used for the controlled variable, and the air flow rate was used for the manipulated variable. A first order plus time delay model was identified and controller parameters were obtained by applying the IMC-PI tuning rule to the identified model. With this controller, we could control the reforming reactor temperature within ${\pm}5^{\circ}C$ over 100 hours. Change of the hot-spot point due to the catalyst degradation was investigated and it could be used to design an adaptive controller.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.99-104
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• 2008

Gas pressure regulators in pressure regulating station reduce high-pressure gas in a process line to a lower. Gas pressure regulators are not flow control devices, they are used to control delivery pressure only. For the safety of pressure regulating station, it is essential to study flow regime and characteristics of a safety valves that is connected to a pressure regulator. For this, it is necessary to understand flow characteristics and the flow rate of upstream component part such as gas pressure regulators in regulating station. In the present study, numerical analysis of flow characteristics and the mass flow rate of a pressure regulator is conducted under the several inlet, outlet conditions and open rates. Then, the numerical result of the mass flow rate is verified with experimental equation from manufacture of pressure regulator. Consequently, the numerical result is comparatively good agreement with values from experimental equation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.1 no.2
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• pp.9-14
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• 2000

State feedback with integral control for a variable air volume(VAV) unit which is recently taken notice of for the energy efficiency and saving in the building is studied to investigate the performance of the digital control methodology for the possible practical application. The digital controller which acquires the targat zone temperature and the air flow rate of the supplied air to the zone controls the opening of the damper in the VAV unit. Simulation results are performed for the conditions including reference changes and external thermal variations. In the simulation. simplified conditioned zone and the damper actuator modelling is considered. and relationships between controller gain Parameters and the system dynamics are investigated.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.222-232
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• 1993

In this paper, we present two sets of fuzzy algorithms for the steam generator level control ; one for the high power operations where the flow error is available and the other for the low power operations where the flow error is not available. These are converted to a PID type controller for the high power case and to a quadratic function form of a controller for the low power case. These controllers are implemented on the Compact Nuclear Simulator at Korea Atomic Energy Research Institute and tested by a set of four simulation experiments for each. For both cases, the results show that the total variation of the level error and of the flow error are about 50% of those by the PI controllers with about one half of the control action. For the high power case, this is mainly due to the fact that a combination of two PD type controllers in the velocity algorithm form rather than a combination of two PI type controllers in the position algorithm form is used. For the low power case, the controller is essentially a PID type with a very small integral component where the average values for the derivative component input and for the controller output are used.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.3
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• pp.175-180
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• 2008

Flow quantity to supply to a coil in floor heating system is important to achieve comfortable indoor air condition in the winter season. The hot water header is used to distribute the water into the coil. Experimental study has been performed using the water header that have 5 branches consisted of flow control valves and automatic shut-off valves. Each branch line connected it with X-L pipe. Experimental tests accomplished it to investigate the flow distribution characteristics of the hot water header. Experimental results show that the selection of the pump head and differential pressure are very important to save running energy of the system, and high differential pressure needs more friction loss in the case of suitable differential pressure for balancing of the header.