• 한국산학기술학회논문지
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• 제16권12호
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• pp.8187-8194
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• 2015

고 중량의 궤도열차를 1G 포스이상 가속하기 위해서는 많은 추진력이 필요하다. 선형동기전동기(LSM)는 이러한 고 추력이 필요한 시스템에 적합하다. LSM의 추진 효율을 높이기 위해서 추진제어시스템은 정밀한 위상제어를 위한 실시간의 정확한 차량위치정보가 필요하다. 그러나 추진제어시스템은 전자석 길이구간마다 트랙에 설치되어져 있는 홀센서로부터 상대적으로 긴 시간간격을 갖는 불연속 위치정보를 수신하게 된다. 본 논문에서는 기존 d-q 방정식을 이용한 기본 전동기 모델을 구성하였다. LSM에 의해 추진되는 궤도열차의 모터모델은 코깅력과 마찰손실을 반영한 동적모델이다. 그리고 궤도열차용 LSM제어를 위해 차량위치 추정기를 기반으로 하는 추진제어 시스템을 제안하였다. 해당 궤도열차의 모터모델을 기반으로 위치관측기를 포함한 토크제어시스템의 특성을 확인하기 위해서 시뮬레이션을 수행하였다. 시뮬레이션 결과는 본 제어시스템이 선형화된 시뮬레이션 모델 분석으로부터 제어기의 대역폭과 위상여유가 충분하다는 것을 보여주고 있으며, 제시한 위치 추정기 기반의 추력제어 알고리즘이 궤도열차의 추력을 제어하는데 효과적임을 확인시켜주었다. 따라서 위치 관측기의 가용성도 확인 할 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제34권4호
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• pp.170-176
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• 2013

Lymphedema is a phenomenon in which fluid is accumulated inside tissues due to the damaged lymphatic systems. Lymphedema can cause complications such as lymphangitis, infection, changes in skin texture, fibrosis, and lymphangiosarcoma. In this study, a lymphedema screening system based on the elasticity of the skin is proposed to easily quantify lymphedema. The developed probe consists of touch sensors, a load cell and hall-effect sensors to measure the indentation force on the skin and the return time of the skin. The developed system can be used to estimate the change in the elasticity of the skin to quantify lymphedema. The system was tested with a thyroid phantom and gelatin phantoms of different concentrations and the resulting force and the time were recorded. It was found that the increase in the elasticity leads to a higher indentation force and shorter return time. This shows that the developed system can monitor the change in the skin elasticity by measuring the return time and the indentation force. The feasibility of the system in clinical applications will be evaluated in the future study.

• 전력전자학회논문지
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• 제13권1호
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• pp.41-45
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• 2008

본 논문에서는 홀센서와 같은 자극위치 센서를 사용하지 않는 Z축 선형 영구자석 동기전동기의 초기 자극위치 추정에 관한 알고리즘을 제안한다. 제안된 알고리즘은 Z축의 경우에 존재하는 중력에 의한 자체하중의 영향을 고려하고, 부하질량 변동에 따른 추정특성 변화를 회피하기 위한 방법을 제시하며, 2단계로 구성되어 있다. 1단계에서는 미리 정한 각도 간격의 시험 q축에 전류를 인가하여 구한 이동거리를 사용하여 근사적인 q축을 추정한다. 2단계에서는 1단계의 추정치를 초기치로 이용하며, 부하질량의 영향을 받지 않도록 하기 위하여 3개의 시험 q축에 인가한 전류에 따른 추력에 대응하는 값을 이용하여 자극위치를 정밀하게 추정한다. 그리고 Z축 PMLSM에 대한 실험 결과를 통하여 제안된 초기 자극위치 추정방법으로 부하질량 조건에 관계없이 정밀하게 자극위치를 추정함을 검증하였다.

• 센서학회지
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• 제16권2호
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• pp.85-90
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• 2007

This paper presents the growth conditions and characteristics of polycrystalline 3C-SiC (silicon carbide) thin films for M/NEMS applications related to harsh environments. The growth of the 3C-SiC thin film on the oxided Si wafers was carried out by APCVD using HMDS (hexamethyildisilane: $Si_{2}(CH_{3})_{6})$ precursor. Each samples were analyzed by XRD (X-ray diffraction), FT-IR (fourier transformation infrared spectroscopy), RHEED (reflection high energy electron diffraction), GDS (glow discharge spectrometer), XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscope) and TEM (tunneling electro microscope). Moreover, the electrical properties of the grown 3C-SiC thin film were evaluated by Hall effect. From these results, the grown 3C-SiC thin film is very good crystalline quality, surface like mirror and low defect. Therefore, the 3C-SiC thin film is suitable for extreme environment, Bio and RF M/NEMS applications in conjunction with Si fabrication technology.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1928-1934
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• 2014

Induction motors are widely used due to their rugged, robust and easy to care features. Since they are heavily used in industry, testing of three phase induction motors have play a vital role. In order to determine motor equivalent circuit parameters, efficiency of motor, squirrel caged laboratory sized an induction motor test setup is prepared. It is suitable for the induction motor with the frame size of 100 and 112. A virtual Instrumentation typed engineering workbench (called as LabVIEW) software packet, is utilized as a graphical user interface program. Motor input power is measured by measuring the input voltage, current and power factor with the help of hall effect typed voltage and current transformers. Also, the output power is measured by measuring the speed and torque with the help of an encoder and torque sensor. All outputs of the voltage and current transformer, encoder and temperature, torque sensors are given to the Data Acquisition Card (DAQ) which acquires the data for processing and then the equivalent circuit parameters, efficiency, performance and loading characteristics are found out, using LabVIEW based user interface. It is suggested to use this test rig for the quality control of produced motors in industry, and an educational experiment setup in the school laboratories.

• 센서학회지
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• 제24권4호
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• pp.219-223
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• 2015

Indium free consisting of three alternating layers GTO/Ag/GTO has been fabricated by radio-frequency (RF) sputtering for the applications as transparent conducting electrodes and the structural, electrical and optical properties of the gallium tin oxide (GTO) films were carefully studied. The gallium tin oxide thin films deposited at room temperature are found to have an amorphous structure. Hall Effect measurements show a strong influence on the conductivity type where it changed from n-type to p-type at $700^{\circ}C$. GTO/Ag/GTO multilayer structured electrode with a few nm of Ag layer embedded is fabricated and show the optical transmittance of 86.48% in the visible range (${\lambda}$ = 380~770 nm) and quite low electrical resistivity of ${\sim}10^{-5}{\Omega}cm$. The resultant power conversion efficiency of 2.60% of the multilayer based OPV (GAG) is lower than that of the reference commercial ITO. GTO/Ag/GTO multilayer is a promising transparent conducting electrode material due to its low resistivity, high transmittance, low temperature deposition and low cost components.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권12호
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• pp.771-777
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• 2000

This paper deals with the design and fabrication of a novel superconducting power supply system, and characteristics have been investigated through experiments. Superconducting power supply consists of rotating and static parts, and superconducting magnet. In this experiment, superconducting foils were placed in parallel within the static part of the machine, pumping currents were measured with respect to rotor speeds and excitation currents. In addition, in order to observe the rotating flux distribution in the superconducting foils, several hall-sensors were placed in it. With the flux distribution acquired, effect of the flux on the superconducting foil during the process of current pumping has been discussed. Also, the general operational characteristics of the superconducting power supply system have been investigated on the basis of the current and voltage data, and magnetic field values acquired through the experiments.

• 제어로봇시스템학회논문지
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• 제20권10호
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• pp.1051-1056
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• 2014

In this paper, we introduce an intelligent robotic arc welding system which exploits sensors like as LVS (Laser Vision Sensor), Hall effect sensor, voltmeter and so on. The use of industrial robot is saturated because of its own limitation, and one of the major limitations is that industrial robot cannot recognize the environment. Lately, sensor-based environmental awareness research of the industrial robot is performed actively to overcome such limitation, and it can expand application field and improve productivity. We classify the sensor-based intelligent arc welding robot system by the goal and the sensing data. The goals can be categorized into detection of a welding start point, tracking of a welding line and correction of a torch deformation. The Sensing data can be categorized into welding data (i.e. current, voltage and short circuit detection) and displacement data (i.e. distance, position). This paper covers not only the explanation of the each category but also its advantage and limitation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.337-339
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• 1998

This paper deals with the design and fabrication of a novel superconducting power supply system, and characteristics have been analyzed through experiments. Superconducting power supply consists of rotating and static parts, and superconducting magnet. In this experiment, the current-pumping characteristics have been analyzed with superconducting sheets placed in parallel within the static part of the machine. In addition, in order to observe the 3-dimensional flux distribution in the superconducting sheet, several hall-sensors were placed in it. With the flux distribution acquired, the effect of the flux on the superconducting sheet during the process of current pumping have been analyzed. Also, general operational characteristics of the superconducting power supply system have been investigated on the basis of the current and voltage data and magnetic field values acquired through the experiments. In this experiment, maximum pumping current has been achieved to about 1280 amps.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.244-246
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• 1999

This paper deals with the design and fabrication of a novel superconducting power supply system, and characteristics have been analyzed through experiments. Superconducting power supply consists of rotating and static parts, and superconducting magnet. In this experiment, the current pumping characteristics have been analyzed with superconducting sheets placed in parallel within the static part of the machine. In addition, in order to observe the rotating flux distribution in the superconducting sheet, several hall-sensors were placed in it. With the flux distribution acquired, the effect of the flux on the superconducting sheet during the process of current pumping have been analyzed. Also, general operational characteristics of the superconducting power supply system have been investigated on the basis of the current and voltage data, and magnetic field values acquired through the experiments.