• Title/Summary/Keyword: Flow control system

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마이크로그리드에서 태양광-연료전지 하이브리드 시스템의 Feeder Flow Mode 운영 기법 (Feeder Flow Control Algorithm for Photovoltaic-Fuel cell Hybrid System in Micro-Grid)

  • 문대성;강기혁;김윤성;서재진;원동준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.161-163
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    • 2008
  • The paper deals with a inverter control scheme to apply feeder flow control in the hybrid system consisted of a photovoltaic system and a fuel-cell system. The inverter operation modes and a feeder control reference is changed by changing of the loads. Simulation results using the PSCAD/EMTDC are presented to establish a inverter control method for a Feeder flow control mode.

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붐방제기용 주행속도 보상식 유량제어부의 동특성 (Flow Compensating Characteristics for the Speed Variation of a Boom Sprayer)

  • 구영모;정재은
    • Journal of Biosystems Engineering
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    • 제23권2호
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    • pp.115-124
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    • 1998
  • Over- and under-application of pesticides to crops have recently become main concerns regarding the environment conservation, product cost and firmer's safety. Thus, a uniform and optimal application method of pesticides was needed. The objective of study was to evaluate flow compensating characteristics of a variable flow control system for a boom sprayer using a laboratory setup. At the most variable conditions, the control system was acceptable with the flowrate control strategy. However, the sprayer control system became unstably fluctuating at the long execution time with small tolerance because of the constant valve on-time. This problem was solved by employing a variable on-time control. The optimal values for the damping ratio and the execution time were 2 and 1.0 sec, respectively, with the tolerances less than 3%. The performance of the control system at the optimal conditions were the response time of 3.8sec and the absolute steady-state error of 0.5% with the stable RCV and ROS ( < 1.0).

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수중발사를 위한 ATP 방식 압축수 방출시스템의 동특성 해석 (Analysis of the Dynamic Characteristics of Pressurized Water Discharging System for Underwater Launch using ATP)

  • 한명철;김정관;김광수
    • 제어로봇시스템학회논문지
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    • 제15권6호
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    • pp.567-572
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    • 2009
  • The underwater launch system using an ATP consists of five parts: compressor tank, proportional flow control servo valve, expulsion spool valve, air turbine pump, and discharge tube. The purpose of this study is to develop an underwater launch system using an ATP and to verify the validity of the system. The proportional flow control servo valve is modeled as a 2nd order transfer function. The projectile is ejected by pressurized water through the air turbine pump, which is controlled by expulsion valve. The mathematical model is derived to estimate the dynamic characteristics of the system, and the important design parameters are derived by using simulations. The computer simulation results show the dynamic characteristics and the possibility of control for underwater launch system.

전달 시간차 방식 초음파 가스 유량계 (Development of an Ultrasonic Gas Flow Meter Using Transit Time Difference)

  • 박상국;황원호
    • 제어로봇시스템학회논문지
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    • 제9권9호
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    • pp.707-713
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    • 2003
  • We investigate the ultrasonic gas flow meter for the measurement of gas volume quantity, which passing through pipe, using the transit time difference method. We have designed a receiving system of an ultrasonic signal and hardware system of a flow meter Also, we have designed an experimental system for the characteristic test and calibration of a gas flow meter system. We have developed an ultrasonic gas flow meter, which has a measurement uncertainty within $\pm$ 1.7 %. For the test, we have compared our system with a difference pressure type flow meter for a few months in the real field. Through the test, we have confirmed that our system have a good reliability and durability. Also, we have confirmed that our system follows very well the variation of gas volume quantity, which was measured by a difference pressure type flow meter.

실별제어 온수분배기의 유량분배 특성 (A Flow Quantity Distribution Characteristics of the Hot Water Header for Individual Room Control System)

  • 성순경
    • 설비공학논문집
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    • 제20권3호
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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.

인공신경망 Feedforward 제어기를 이용한 좌심실 보조장치의 제어실험 (Control of Left Ventricular Assist Device Using Neural Network Feedforward Controller)

  • 정성택;김훈모;김상현
    • 한국정밀공학회지
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    • 제15권4호
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    • pp.83-90
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    • 1998
  • In this paper, we present neural network for control of Left Ventricular Assist Device(LVAD) system with a pneumatically driven mock circulation system. Beat rate(BR), Systole-Diastole Rate(SDR) and flow rate are collected as the main variables of the LVAD system. System modeling is completed using the neural network with input variables(BR, SBR, their derivatives, actual flow) and output variable(actual flow). It is necessary to apply high perfomance control techniques, since the LVAD system represent nonlinear and time-varing characteristics. Fortunately. the neural network can be applied to control of a nonlinear dynamic system by learning capability In this study, we identify the LVAD system with neural network and control the LVAD system by PID controller and neural network feedforward controller. The ability and effectiveness of controlling the LVAD system using the proposed algorithm will be demonstrated by experiment.

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온수분배기용 유량제어밸브의 개발 (Development of Flow Control Valves for Hot Water Distribution Manifolds)

  • 권우철;윤준용;유선학
    • 한국유체기계학회 논문집
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    • 제13권4호
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    • pp.11-17
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    • 2010
  • The developed control valves, installed on the hot water distribution manifolds for the floor heating system, consist of the balancing valves and the shut-off valves. The balancing valve was designed to improve the flow control performance and to reduce the noise emitted from the valve by modification of the general V port. The port of the shut-off valve was designed with two ceramic plates, working by rotating upper plate, to improve the duration and to reduce the noise. For the evaluation of the new valves, the flow rate was measured and noise level test was carried out. The test results showed that the error of the flow rate accuracy test for the flow balance of each manifold circuit was less than ${\pm}3%$ and the noise level was less than 35 dB(A).

주행속도 보상형 붐방제기의 개발 (Development of a Flow Compensating Boom Sprayer for the Speed Variation)

  • 구영모;정재은
    • Journal of Biosystems Engineering
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    • 제23권3호
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    • pp.211-218
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    • 1998
  • A variable flow-controlled boom sprayer was developed and evaluated. Field tests were conducted to evaluate the adoptability of the sprayerr with optimal conditions. Negative response time was obtained from the field test because pump and PTO were interlocked with the speed of sprayer. Another reason for the negative value was due to the definition of the response time. With constant on-time control, the system was unstable at the conditions of small tolerance and long control interval. The performances of the spray system were stable and accurate. The stable and synchronous responses were achieved with a variable on-time control. The flow control system with an optimal condition (1.0 sec of control interval, 2 of damping ratio, 1% of tolerance) provided the proper performance for uniform spraying. A standard operating procedure of the flow compensating boom sprayer for the ground speed variation was presented and recommended.

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PASSlVE SHOCK CONTROL IN TRANSONIC FLOW FIELD

  • Matsuo S;Tanaka M;Setoguchi T;Kashimura H;Yasunobu T;Kim H.D
    • 한국전산유체공학회지
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    • 제10권1호
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    • pp.80-86
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    • 2005
  • In order to control the transonic flow field with a shock wave, a condensing flow was produced by an expansion of moist air on a circular bump model and shock waves were occurred in the supersonic parts of the fields. Furthermore, the additional passive technique of shock-boundary layer interaction using the porous wall with a cavity underneath was adopted in this flow field. The effects of these methods on the shock wave characteristics were investigated numerically. The result showed that the flow fields might be effectively controlled by the suitable combination between non-equilibrium condensation and the position of porous wall.

제어밸브 유량특성에 레이놀즈 수가 미치는 영향 (Effect of Reynolds Number on the Flow Characteristics of a Control Valve)

  • 정태규
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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    • pp.995-999
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    • 2017
  • 제어밸브의 유량계수에 영향을 미치는 인자들을 파악하고 그 영향을 분석하였다. 제어밸브의 유량계수는 레이놀즈 수, 연결 배관의 형상과 표면 조도 등에 영향을 받는다. 따라서 유량계수를 상수로 취급할 수 없다. 그러므로 로켓엔진과 같이 정확한 유량계수를 요구하는 시스템에서 사용할 목적으로 제어밸브의 유량계수를 측정할 때는 실제 사용 환경과 유사한 레이놀즈 수 영역에서, 동일한 조도 및 형상을 가지는 입출구 배관을 사용하여 측정해야 한다.

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