• 한국전자파학회논문지
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• 제7권1호
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• pp.43-52
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• 1996

비가역성 쌍토로이드 페라이트 변위기를 설계, 제작하고 그 특성 실험올 하였다. 변위기의 최적 칫수를 구하기 위해 ABCD 행렬 방법을 사용하였으며, 빈 도파관 부분과 페라이트가 삽입된 부분과의 임피던스 정합을 위해 $\lambda$/4 2단 변환기를 이용하였다. 변위기를 구동시키기 위한 구동회로를 제작하 였으며, 중심주파수 9.3GHz, 동작대역폭 400MHz 에서 측정한 변위기의 삽입손실과 VSWR은 각각 1.2clB, 1.16미만으로써 만족할만한 결과를 얻었다. 또한, 페라이트의 특성이 온도변화에 종속적이기 때문에 온도보상기법을 통해 온도에 따른 변위차 변화량을 보상하였으며, 온도보상결과 $-10^{\circ}C~+60^{\circ}C$사이에 $\pm4^{\circ}$ 이내의 위상오차를 얻을 수 있었다.

• 한국화재소방학회논문지
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• 제20권1호
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• pp.77-82
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• 2006

본 연구에서는 온도가 보상된 압력을 제연구역의 기준압력으로 설정하기 위한 공학적인 메커니즘과 보상방법을 정립하였고, 통합 제연시스템의 컨트롤러의 개발을 위한 프로세스, 알고리즘 확립과 엔지니어링 데이터의 구축으로 신뢰성이 확보된 통합 제연시스템의 컨트롤러를 개발하였다. 컨트롤러를 개발함으로서 비제연구역의 압력측정을 위해서 별도로 설치되는 압력측정관을 생략할 수 있어 제작단가와 설치비용 및 작업공수를 줄일 수 있고, 층별 제연구역의 차압측정을 위한 비제연구역의 압력측정포트를 시스템에 일체화함으로서 차압의 정밀도를 향상시킬 수 있다. 기존의 개별제어 방식에서 통합 제연시스템의 컨트롤러로부터 중앙집중식 통합관리를 함으로서 보다 정확하고 신뢰성 있는 차압을 얻을 수 있으며, 제연시스템에 유연성을 부과시킬 수 있을 것으로 본다. 또한 통합 제연시스템의 기틀을 마련하고 제연의 유연성을 주며 방재성능을 향상시킬 것으로 본다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.153-159
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• 2012

In photovoltaic system, the characteristic of photovoltaic module such as open circuit voltage and short circuit current will be changed because of cell temperature and solar radiation. Therefore, a boost converter of the PV system connects between the output of photovoltaic system and DC link capacitor of grid connected inverter as controlling duty ratio for maximum power point tracking(MPPT). This paper shows the dynamic characteristic of the boost converter by comparing single-loop control algorithm and two-loop control algorithm using both analog and digital control. The proposed both compensation method has been verified with computer simulation and simulation results obtained demonstrate the validity of the proposed control schemes.

• 한국태양에너지학회 논문집
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• 제29권6호
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• pp.1-13
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• 2009

Photovoltaic conditioning systems normally use a maximum power point tracking (MPPT) technique to deliver the highest possible power to the load continuously when variations occur in the insolation and temperature. A unique method of tracking the maximum power points (MPPs) and forcing the boost converter system to operate close to these points is presented through deriving small-signal model and transfer function of boost converter considering input capacitor. This paper aims at modeling boost converter including fairly large equivalent series resistance(ESR) of input reservoir capacitor by state-space-averaging method and PWM switch model and compares both methods using Bode plots. In the future, properly designed controller for compensation will be constructed in 3kw real system for maximum photovoltaic power tracking control.

• 한국정밀공학회지
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• 제19권7호
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• pp.80-87
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• 2002

Liquefied petroleum gas (LPG) is used in spark ignition (SI) engines. Fuel injection rate of an injector is affected by fuel temperature and pressure in LPG liquid injection systems for either a multi-point-injection (MPI) or a direct injection (DI) engine. Even fuel injection conditions are varied, the air-fuel ratio should be accurately controlled to reduce exhaust emissions. In this study, a correction factor fur the fuel injection rate of an injector is derived from density ratio and pressure difference ratio. A compensation method of injected fuel amount is proposed for a fuel injection control system. The experimental results for the LPG liquid injection system in a SI engine show that this system works well fur a full range of engine speed and load condition, and the air-fuel ratio is accurately controlled by the proposed correction factor.

• 한국양식학회지
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• 제7권1호
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• pp.1-7
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• 1994

긴잎돌김 (Porphyra pscudolineris Ueda)의 엽상체와 배양 사상체에 미치는 온도와 광도의 영향을 구명하였다. 엽상체와 사상체의 총 광합성의 적정 온도는 각각 $25\~30^{\circ}C$, $20^{\circ}C$로 나타났다. 엽상체와 사상체에서 광도에 따른 광합성율은 공히 10,000 lux 이상에서 광합성율이 일정한 값에 도달하는 광포화 곡선을 나타내었다. 엽상체의 광 보상점은 2,100 lux, 사상체의 광 보강점은 900 lux였으며, 사상체의 광합성능은 엽상체의 5-10배에 해당하였다. 이로써 사상체는 낮은 광도하에서도 광합성을 수행할 수 있음을 알 수 있다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.285-288
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• 2007

3차원 초음파 센싱에 의해 획득한 데이터로부터 물체의 부피를 자동으로 측정하고 분류적재 관리하는 임베디드시스템을 프로세서 기반으로 구현한다. 부피측정은 3개의 초음파 센서에서 획득한 데이터에서 높이와 폭은 물체가 컨베이어를 통과할 때 3 값을 기준 값과 비교하여 측정하고 길이는 물체가 처음 감지된 시점부터 범위를 벗어날 때까지의 시간을 물체의 이동속도에 대입하여 측정한다. 또한 센서의 온도 변화에 속도가 변하기 때문에 환경에 따라 보정하고 물체가 정방향이 아닐 경우 센싱값을 평균하여 오차를 줄인다. 실험은 직육면체를 기준하였으며 포장된 물류를 크기별로 분류하고 창고 및 이동체에 적재 할 경우 실용적으로 활용가능성을 높인다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.65-68
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• 2001

In the vector control methods of induction motor, the stator current is divided into the flux and torque component current. By controlling these components respectively, the methods control independently flux and torque as in the DC motor and improve the control effects. To apply the vector control methods, the position of the rotor current is identified. The indirect vector control use the parameters of the machine to identify the position of rotor flux. But due to the temperature rise during machine operation, the variation of rotor resistance degrades the vector control. To solve the problem, the q-axis is aligned to reference frame without phase difference by comparing the real flux component with the reference flux component. Then to compensate the slip, PI controller is used. The proposed method keeps a constant slip by compensating the gain of direct slip frequency when the rotor resistance of induction motor varies. To prove the validations of the proposed algorithm in the paper, computer simulations is executed.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권11호
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• pp.654-659
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• 2005

An improved power supply for APD(Avalanche Photo Diode) with a received optical power monitoring circuit allows the received optical power increase temporary without of the degradation of the electrical signal. For the cost reduction and simple fabrication, an improved power supply has been proposed that it was designed for driving a APD as a receiving device of a wireless optical transmission system. It was demonstrated that it was possible to improve a dynamic range by compensating the temperature coefficient of the APD up to 1.0 V/$^{\circ}C$ through the power supply. Also, for an efficient transmission at the receiver end, a simple structure of a single cylindrical micro-lens configuration was used in conjunction with the laser diode to partially compensate a laser beam ellipticity. For this purpose, an astigmatism introduced by the micro-lens is utilized for the additional compensation of the beam ellipticity at the receiver end. In this paper, it is demonstrated that an efficient beam shaping is realized by using the proposed configuration consisting of the single lens attached to the laser diode.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권3호
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• pp.125-132
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• 2002

PMSMS (permanent magnet synchronous motors) are widely used in industrial applications and home appliances because of their high torque to inertia ratio, superior power density, and high efficiency. For high performance control, accurate informations about the rotor position is essential. Sensorless algorithms have lately been studied extensively due to the high cost of position sensors and their low reliability in harsh environments. A novel position sensorless speed control for PMSMs uses indirect flux estimation and is presented in this paper. Rotor position and angular velocity are estimated by the proposed indirect flux estimation. Linkage flux and magnetic field flux are calculated by the voltage equations and the measured phase current without any integration. Instead of linkage flux calculation with integral operation, indirect flux and differential magnetic field are used for the estimation of rotor position. A proper rejection technique fur current noise effect in the calculation of differential linkage flux is introduced. The proposed indirect flux detecting method is free from the integral rounding error and linkage flux drift problem, because differential linkage flux can be calculated without any integral operation. Furthermore, electrical parameters of the PMSM can be measured by the proposed TCM (time compression method) for soft starting and precise estimation of rotor position. The position estimator uses accurate electrical parameters that are obtained from the proposed TCM at starting strategy. In the operating region, a proper compensation method fur temperature effect can compensate fir the estimation error from the variation of electrical parameters. The proposed novel position sensorless speed control scheme is verified by the experimental results.