• 한국산업융합학회 논문집
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• 제17권3호
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• pp.93-102
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• 2014

Recently the interest in permanent magnet alternating motor using for electric compressor become great. Especially the research on Interior Permanent Magnet Motor has been doing actively for its advantages in the energy density and the efficiency. In order to control the output of motor to the desired value, the current control or speed control of motor are required. The accurate detection of rotor position and speed information are necessary for the control of motor. In general, the encoder, hall sensor, and resolver are used to obtain the information of motor position and speed and the speed detection algorithm, M/T method, is applied. However, the M/T method causes the error depending on rotor speed. Therefore, this M/T speed detection method is not perfect. In this paper, it is proposed that the PI control with a 1st transfer function and the integration element between velocity and position are composed in series and this feeds back to the reference value of position angle. The proposed algorithm is a function of the integral elements 2nd term, speed element, is used as an output. Thus, it is possible to detect the correct speed by configuring like the mechanical structure similarly. The proposed algorithm is verified by using PSIM DLL and is applied to the BLAC motor drive. And also it is confirmed that this system estimates the accurate speed regardless of rotor speed changes. As a example, the experimental results and simulations shows that the proposed method is very effective.

• 센서학회지
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• 제8권2호
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• pp.189-194
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• 1999

고주파 마그네트론 스퍼터링법으로 증착된 순수한 ZnO 박막 및 Al이 포핑된 ZnO(AZO) 박막의 열처리온도 및 열처리분위기에 따른 전기적 및 광학적 특성을 4점 측정법 및 Hall 효과 측정법을 통한 비저항의 측정과 광투과도의 측정을 통하여 조사하였다. 대기중에서 열처리된 ZnO 박막 및 ZnO:Al 박막은 각각 $200^{\circ}C$ 및 $300^{\circ}C$에서 비저항이 현저하게 증가하였으며 수소 플라즈마 분위기에서 열처리된 ZnO 박막은 $500^{\circ}C$의 열처리온도에서 약 1승 정도 비저항이 증가하였으나 ZnO:Al 박막은 열처리온도에 무관하게 비저항이 거의 일정하였다. 550 nm 에서 측정된 광투과도는 90% 정도로 시편의 불순물도핑, 열처리온도 및 열처리분위기에 무관하게 일정한 것으로 나타났다.

• 센서학회지
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• 제15권6호
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• pp.397-405
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• 2006

Single crystal $AgGaSe_{2}$ layers were grown on thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $AgGaSe_{2}$ source at $630^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $AgGaSe_{2}$ thin films measured with Hall effect by van der Pauw method are $4.05{\times}10^{16}/cm^{3}$, $139cm^{2}/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $AgGaSe_{2}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$=1.9501 eV-($8.79{\times}10^{-4}{\;}eV/K)T^{2}$/(T+250 K). The crystal field and the spin-orbit splitting energies for the valence band of the $AgGaSe_{2}$ have been estimated to be 0.3132 eV and 0.3725 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}So$ definitely exists in the ${\Gamma}_{5}$ states of the valence band of the $AgGaSe_{2}$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1}-$, $B_{1}-$, and $C_{1}-$exciton peaks for n=1.

• 센서학회지
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• 제14권3호
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• pp.160-168
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• 2005

ZnO epilayer were synthesized by the pulesd laser deposition(PLD) process on $Al_{2}O_{3}$ substrate after irradiating the surface of the ZnO sintered pellet by the ArF(193 nm) excimer laser. The epilayers of ZnO were achieved on sapphire ($Al_{2}O_{3}$) substrate at a temperature of $400^{\circ}C$. The crystalline structure of epilayer was investigated by the photoluminescence. The carrier density and mobility of ZnO epilayer measured with Hall effect by van der Pauw method are $8.27{\times}1016cm^{-3}$ and $299cm^{2}/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the ZnO obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$=3.3973 eV-($2.69{\times}10^{-4}$ eV/K)$T^{2}$/(T+463K). The crystal field and the spin-orbit splitting energies for the valence band of the ZnO have been estimated to be 0.0041 eV and 0.0399 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_{6}$ states of the valence band of the ZnO. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1}-$, $B_{1}-$, and $C_{1}-$exciton peaks for n = 1.

• 센서학회지
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• 제16권6호
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• pp.419-427
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• 2007

Single crystal $ZnIn_{2}S_{4}$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $450^{\circ}C$ with the hot wall epitaxy (HWE) system by evaporating the polycrystal source of $ZnIn_{2}S_{4}$ at $610^{\circ}C$ prepared from horizontal electric furnace. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $ZnIn_{2}S_{4}$ thin films measured with Hall effect by van der Pauw method are $8.51{\times}10^{17}\;electron/cm^{-3}$, $291{\;}cm^{2}/v-s$ at 293 K, respectively. The photocurrent and the absorption spectra of $ZnIn_{2}S_{4}$/SI(Semi-Insulated) GaAs(100) are measured ranging from 293 K to 10 K. The temperature dependence of the energy band gap of the $ZnIn_{2}S_{4}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)$=2.9514 eV. ($7.24{\times}10^{-4}\;eV/K$)$T^{2}$/(T+489 K). Using the photocurrent spectra and the Hopfield quasicubic model, the crystal field energy(${\Delta}cr$) and the spin-orbit splitting energy(${\Delta}so$) for the valence band of the $ZnIn_{2}S_{4}$ have been estimated to be 167.8 meV and 14.8 meV at 10 K, respectively. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1}$-, $B_{1}$-, and $C_{41}$-exciton peaks.

• 센서학회지
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• 제16권6호
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• pp.457-461
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• 2007

This paper describes the characteristics of poly (polycrystalline) 3C-SiC grown on $SiO_{2}$ and AlN substrates, respectively. The crystallinity and the bonding structure of poly 3C-SiC grown on each substrate were investigated according to various growth temperatures. The crystalline quality of poly 3C-SiC was improved from resulting in decrease of FWHM (full width half maximum) of XRD and FT-IR by increasing the growth temperature. The minimum growth temperature of poly 3C-SiC was $1100^{\circ}C$. The surface chemical composition and the electron mobility of poly 3C-SiC grown on each substrate were investigated by XPS and Hall Effect, respectively. The chemical compositions of surface of poly 3C-SiC films grown on $SiO_{2}$ and AlN were not different. However, their electron mobilities were $7.65{\;}cm^{2}/V.s$ and $14.8{\;}cm^{2}/V.s$, respectively. Therefore, since the electron mobility of poly 3C-SiC films grown on AlN buffer layer was two times higher than that of 3C-SiC/$SiO_{2}$, a AlN film is a suitable material, as buffer layer, for the growth of poly 3C-SiC thin films with excellent properties for M/NEMS applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.343-345
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• 1998

By computer simulation, the pattern of magnetic field distribution on the Nb-foil of a rotating flux type superconducting power supply has been calculated. Using the results, the current pumping rate has been calculated and compared with the results obtained by the experiment. The experiment has been executed with small-size flux-rump in the environment of LN2 and LHe in order to compare the pattern of magnetic filed in the superconducting state and in the normal state. Five hall-sensor was located on the center, right side, left-side, upper side, lower side of the Nb-foil in order to obtain more accurate pattern of the magnetic field generated by rotating pole. In the simulation, the effects of the excitation-magnet and the iron core located at the inner-side and circumference of the magnet have been considered. By comparing the data from the experiment and the results from the simulation, the size of normal spot estimated. At the same time, by calculating the linkage flux, the current-pumping-rate has been obtained. Consequently, the results obtained from experiment and simulation coincided as expected.

• 한국자기학회지
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• 제23권1호
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• pp.18-25
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• 2013

배관용 비파괴 검사에서 자기누설방식을 이용하여 배관의 결함을 검출하도록 개발된 탐상 시스템 장비를 MFL PIG(Magnetic Flux Leakage Pipeline Inspection Gauge)라 한다. 이 장비는 투자율이 큰 금속 배관의 길이 방향인 축방향으로 자기장을 형성하고, 결함이 있는 부분에 발생하는 누설 자속 신호를 홀센서를 이용하여 검출한다. 하지만 MFL PIG는 배관에 축방향으로 발생한 미소결함에 대해서는 누설 자속의 발생량이 미세하여 결함 유무를 판별하기 어렵다. 본 논문에서는 배관에 발생한 축방향 미소결함을 검출하기위해 CMFL(Circumferential MFL) PIG를 적용하였고, 결함 주위에 발생한 누설 자속 신호의 크기 및 분포를 3차원 정자계 유한요소법을 이용하여 검출 및 분석하였다. 이러한 검출 신호로부터 길이, 폭, 깊이와 같은 결함의 형상을 판정하는 기법을 제안하였고 이를 CMFL PIG 모의 성능 실험을 통하여 비교 및 검증하였다.

• 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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• 제24권6호
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• pp.364-367
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• 2015

Tin oxide thin films were fabricated on glass substrates by the successive ionic layer adsorption and reaction (SILAR) method at room temperature and ambient pressure. Before measuring their properties, all samples were annealed at $500^{\circ}C$ for 2 h in air. Film thickness increased with the number of cycles; X-ray diffraction patterns for the annealed $SnO_2$ thin films indicated a $SnO_2$ single phase. Thickness of the $SnO_2$ films increased from 12 to 50 nm as the number of cycles increased from 20 to 60. Although the optical transmittance decreased with thickness, 50 nm $SnO_2$ thin films exhibited a high value of more than 85%. Regarding electronic properties, sheet resistance of the films decreased as thickness increased; however, the measured resistivity of the thin film was nearly constant with thickness ($3{\times}10^{-4}ohm/cm$). From Hall measurements, the 50 nm thickness $SnO_2$ thin film had the highest mobility of the samples ($8.6cm^2/(V{\cdot}s)$). In conclusion, optical and electronic properties of $SnO_2$ thin films could be controlled by adjusting the number of SILAR cycles.