• 한국전자통신학회논문지
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• 제10권4호
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• pp.433-439
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• 2015

CCTV용 함체 내부는 일정한 습도와 온도를 유지시켜 습윤에 의한 단락방지, 온도차에 의한 결로방지, 고온방지 등의 항온항습장치가 요구되며 이를 대응한 함체에 최적화된 형태와 구조, 에너지활용 정도의 항온항습 자동제어장치개발이 필요하다. 함체내부에 있는 고가의 영상장비를 온도 변환에 따른 해저드로부터 장치보호, 단락사고를 예방할 수 있는 항온항습 제어장치가 필요하다. 이는 영상기록 및 현장상황에 신뢰성 있는 영상의 저장 및 전송을 위한 부속장치가 절대적으로 요구되는 시스템이다.

• 제어로봇시스템학회논문지
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• 제12권12호
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• pp.1249-1255
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• 2006

This paper presents a constant power control logic for perfect starting a microtubine in vehicle. Under extremely low temperature, performance of the start-up system is severely dropped than that of room temperature because of increasing of load of mechanical parts including engine core and drop of the lead-acid battery capacity. Unfortunately, performance drop of lead-acid battery makes severe problems that cause a malfunction of fuel and lubrication system and power fail of digital devices. So we propose the new start-up logic by constant output power control of lead-acid battery using PWM inverter controller for preventing above problems and keeping good performance of start-up system for microturbine. Also, we prove usefulness of new start-up logic through experimental results under $-32^{\circ}C$ ambient temperature.

• 설비공학논문집
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• 제28권2호
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• pp.69-74
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• 2016

Most hot water heating valves for apartments are constant-flow types, which limit the flow rate through an individual household for even distribution of heating water to other households. The constant-flow type is implemented by an on-off control. As a result, heating water is supplied intermittently and hence, indoor air temperature also fluctuates. Returning water temperature is also high, which reduces energy efficiency. To implement continuous feedback control, the indoor temperature dynamics was simulated to fit a measured temperature history by a state-of-the-art physical model. From the model, it was found that the most important disturbance is outdoor temperature and its effect on indoor temperature lasts about an hour. To cope with the slow response and the significant disturbance, a prediction control with proportional feedback is proposed. The control was found to be successful in implementing continuous heating water flow and improved indoor temperature control.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.28-31
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• 1997

This paper describes the quick and precise controlling method for home-applied refrigerator. The proposed controller is based on the fuzzy logic control method and is designed for better performance in maintaining the constant temperature of the refrigerator. The temperature of the refrigerator is controlled by the cooling air blowing fan motor which is put on, off according to fuzzy logic controller. Finally, I study the performance of the proposed controller through the computer simulation about the approximated model of the refrigerator.

• 한국연초학회지
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• 제13권1호
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• pp.13-18
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• 1991

This experiment carried out to review influence of relative humidity, temperature and net weight on cigarette hardness for the uniformal control of cigarette quality. Obtained results are as follows: 1. The difference in the cigarette physical properties of constant hardness control is considerably lower than that of constant net weight control. 2. Contribution rate for cigarette hardness is relative humidity > net weight > temperature. 3. The multiple regression equation of cigarette hardness related with relative humidity, temperature and net weight is calculated as follows.

• 한국지열·수열에너지학회논문집
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• 제14권4호
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• pp.27-34
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• 2018

This study compared constant water bath performances of conventional water-cooled refrigerator and electric heater with an air-cooled VRF chiller and electric heater equipped with optimal control algorithm. In heating mode, the air cooled VRF chiller and electric heater combination reduced the set temperature arrival time by an average of 42 minutes, and energy was also reduced by 18%. In cooling mode, the two systems took 70 minutes to reach the set temperature and showed no difference. Energy was reduced by 33.5% with the new system. For constant temperature maintaining experiment, after reaching the set temperature of $15^{\circ}C$, $20^{\circ}C$ and $22^{\circ}C$, temperature deviations were all in the range of $-0.2^{\circ}C$ to $+0.1^{\circ}C$. Energy was reduced by an average of 84.9%. Through this study, possibility of precise temperature control by an air cooled VRF chiller system was confirmed.

• Journal of the Korean Wood Science and Technology
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• 제22권1호
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• pp.12-19
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• 1994

An electrically heated experimental lumber dry kiln was retrofitted with a computer-based control system to control kiln conditions more precisely and monitor and record several kiln variables. Flat-sawn 2.5cm-thick Pinus densiflora boards were dried in constant temperature process(65$^{\circ}C$ & 50~60 %RH) and continuously rising temperature process, respectively. The average drying rate in continuously rising temperature process was 5.7 %/hr, which was above 3 times faster than that in constant temperature process. But, the average rate of case-hardening and moisture difference between shells and cores of boards dried in continuously rising temperature process were 82 % and 5.5 %, respectively, which were much larger than those of boards dried in constant temperature process.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.53-57
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• 2012

In this paper, by designing 20 W class driving circuit for driving high-power LED (Light Emitting Diode), we are going to comparatively carry out the analysis of characteristics for power circuit according to each design method. In this case, 200 V 60 Hz was performed as input data. The electrical characteristics such as voltage, current and ripple are checked for constant current circuit and constant voltage circuit in the LED module. In addition, as the ripple has an influence on illumination of LED light, low temperature working (-20 [$^{\circ}C$]) and high temperature working(80 [$^{\circ}C$]) are measured to make sure the ripple characteristics in accordance with temperature. In low temperature operation -20 [$^{\circ}C$] measurements, both constant current circuit and constant-voltage circuit were less impacted on input fluctuation, whereas in the high temperature operation 80 [$^{\circ}C$], current voltage in constant voltage circuit was surge after 430 [hour]. Voltage current ripple of constant current circuit was much less than constant voltage circuit, therefore we can show that constant current circuit is more stable.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.21-24
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• 2002

The vector control system of an induction motor is the high performance drive system to achieve the instantaneous torque control. The vector control system is greatly divided into the direct control, and the indirect control that the most widely is used, The indirect vector control needs the rotor time constant, which changes widely according to the temperature, frequency, and current amplitude. The incorrect time constant leads to the saturation of magnetic flux or under-excitation phenomena. As a result, that deteriorate the control performance. Therefore, in this paper, the effect of time constant variation is investigated and its on-line tuning algorithm is proposed. The time constant using the torque angles was calculated and that of the validity of algorithm proposed was proved through the computer simulation and the experiment.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.83-84
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• 2010

This paper reviews the performance difference between constant voltage control and constant current control in LED driver. Simulations of both control methods are performed for performance comparison especially with temperature variation. The results show that constant current control method is inherently better than constant voltage control for LED drive.