• 한국기계가공학회지
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• 제14권5호
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• pp.113-119
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• 2015

The technical development of electric vehicles has been actively proceeding because of the reduction of oil resources and need for eco-friendly vehicle technology. In particular, an electronic control unit is an important element in the technology of electric vehicles due to the motor drive system. This paper concerns an experimental study on the thermal analysis of the steering control ECU structure for an electric vehicle. The ECU unit is designed for eight heat sinks for the thermal analysis of the ECU structure. The thermal analysis characteristics of the ECU structure are evaluated by the temperature distribution, heat flow, von Mises stress, total translation, and external surface temperature measurement of the ECU unit.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1304-1308
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• 2005

This paper presents the case that the existing analog control systems were retrofitted with digital DCS(Distributed Control System)s for boiler unit in thermal power plant. Replacement of existing worn-out or obsolete analog control systems has been considered. Replacement of existing analog control systems with another analog control systems has lots of difficulties in maintaining the systems due to being out of stock. Due to those difficulties, existing analog control systems have been retrofitted with digital DCSs in many industrial sites. KEPRI(Korea Electric Power Research Institute) accomplished the project that retrofitted analog control systems with the developed DCSs for boiler unit in middle-scale coal-fired thermal power plant. The benefits of an upgrade to digital control include a increase of reliability due to system redundancy, ease of modifying the control logic and the parameters of function block, ease of maintenance due to available spare parts, improvement of information display, ease of modifying MMI(Man Machine Interface) displays, a increase in system availability, and improvement of control performance. This paper describes how to use the parameters of existing analog controllers, the implementation of digital PID controller, control system configuration for boiler unit in thermal power plant, some boiler control loops, control result during commissioning, and the comparison of boiler characteristic test data after retrofitting with the existing test data.

• 한국항공우주학회지
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• 제50권10호
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• pp.729-737
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• 2022

하반기에 발사 예정인 차세대소형위성2호(NEXTSat-2)에 탑재된 고상-액상 상변화물질 열제어장치(Phase Change Material Thermal Control Unit, PCMTCU)의 비행모델에 대한 위성 차원 열진공시험 결과로부터 융해-응고에 따른 작동과정을 분석하였다. 시험결과 PCM의 상변화는 발열부품의 온도 안정화에 기여함을 확인하였다. 시험에서 계측된 온도변화를 이용하여 타당한 정도의 정확도를 갖도록 PCMTCU의 열해석모델에 대한 보정을 수행하였다. 보정된 열해석모델로써 임무궤도의 정상 작동에 따른 PCMTCU의 주기적 온도변화를 예측하였으며, PCM의 액상분율로써 정량적 기여도를 평가하였다. 향후 임무궤도에서의 비행자료를 수신하여 PCMTCU의 우주 환경 검증을 완료할 예정이다.

• International Journal of Air-Conditioning and Refrigeration
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• 제11권1호
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• pp.10-16
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• 2003

The present study performs an experimental measurement on transient thermal response of an air-conditioned space by a variable air volume (VAV) system with a PI(pro-portional-integral) control logic. A thermal chamber with a PI controlled VAV unit is constructed to verify the previously suggested stratified multi-zone model. The effects of thermal parameters and control parameters such as supply air temperature and PI control factor are investigated by implementing the thermal chamber test. The experimental results obtained show that transient behavior of the air-conditioned space-temperature is in good accordance with the simulation results of the stratified thermal model.

• 항공우주기술
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• 제10권2호
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• pp.20-28
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• 2011

저궤도 관측위성의 광학탑재체는 궤도에서 임무수행을 뒷받침하는 위성 본체와 열적으로 분리되어 각각 독립된 열제어를 할 수 있도록 개발된다. 광학탑재체는 내부에 작동하는 동안에 높은 발열량으로 순간적으로 온도가 상승하는 부품 박스인 FPA(Focal Plane Assembly)의 열을 외부로 방출하기 위한 히트파이프, 방열판으로 구성된 냉각 장치(Cooling Unit)를 가지고 있다. 이러한 냉각 장치는 고온 조건에서 내부 발열을 빠르게 외부로 방출할 수 있는 히트파이프의 성능과 충분한 면적의 방열판 면적을 확보하도록 설계되어야 하고, 동시에 저온 조건에서 최저 온도 이상을 유지하는 위한 히터설계도 포함해야 한다. 본 연구에서는 먼저 FPA 냉각 장치의 열제어 요구조건과 현재 열설계 기준의 열해석 결과를 통하여 히터설계에 대한 검토와 설계 제한 조건을 분석을 하였다. 또한 열해석을 이용한 효율적이고 경제적인 위성 히터설계 방식을 제시하고, 이것을 FPA 냉각 장치의 히터설계에 적용하여 개선된 히터설계 요소를 찾았다.

• 대한기계학회논문집B
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• 제27권8호
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• pp.1042-1050
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• 2003

A heating flow discharged from a 4-way ceiling type indoor unit has been investigated to determine the design parameters for the optimal flow control. The flow was measured by a PIV(particle image velocimetry) system and an experimental model of 1/10 scale with a transparent room was devised by satisfying the Archimedes number. This similarity is generally used in cases where the forced convection has similar magnitude of the natural convection. To optimize the heating flow, several vane angles and vane control algorithms of cross and right angle controls were considered. Regarding the vane angle, experimental results show that 30$^{\circ}$is an optimal angle to avoid re-suction flows without significant increase in flow noise. Temperature distribution measured in the environmental chamber ensures the increased thermal comfort when compared to the case, 60$^{\circ}$angle. At the optimal angle, applying open/close control gives rise to more uniform distribution of the heating flow than without control. Especially, the cross-control seems to be satisfactory for thermal comfort.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.533-536
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• 2002

A heating flow discharged from a 4-way ceiling type indoor unit has been investigated using a PIV(particle image velocimetry) system For the PIV measurements, an experimental model of 1/10 scale with a transparent room was devised by satisfying the Archimedes number, which is generally used in case that the forced convection has the similar magnitude as the natural convection. To optimize the heating flow, several vane angles and vane control algorithms of cross and right angle controls were considered. Regarding the vane angle, the experimental results show that it should be less than $30^{\circ}$ to avoid re-suction flows which decrease the performance of the air-conditioner. At the vane angle of $30^{\circ}$, applying open/close control gives nae to more uniform distribution of the heating flow than without control. Especially, the cross-control seems to be satisfactory for the thermal comfort.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 추계학술대회 논문요약집
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• pp.277-277
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• 2003

• 한국생산제조학회지
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• 제8권1호
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• pp.28-34
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• 1999

According to the development of tool material and the improvement of machinability of cutting material like aluminium alloy, the higher spindle speed is needed. However, the higher speed causes the heat generation of bearings, the deformation of spindle unit parts, and the rotational accuracy of spindle to be worse. Therefore, it is essential to analyze and control the heat generation and the thermal behavior of spindle unit in order to have higher speed and better rotational accuracy. This paper shows the analogy between the analyzation of heat generation and thermal behavior of high speed spindle system by finite element method and the test results of actual temperature rise through running test, and shows the necessity of cooling the spindle and inner ring side of bearings for the thermal balance of high speed spindle system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.195-198
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• 1996

The control objective of drum level of boiler in thermal power plant is to maintain drum level at constant setpoint regardless of disturbance such as main steam flow. The initial response of the drum level loop process is in a direction opposite to the final response. The drum level loop shows inverse response when the power is changed abruptly. We adopt fuzzy controller using knowledge base considering system dynamics for controlling drum level. Finally, the simulation result using the digital simulator for boiler system in Seoul Power Plant Unit 4 shows the validity of fuzzy controller.