• Journal of Power Electronics
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• 제10권2호
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• pp.203-209
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• 2010

This paper describes the development of a three-phase line-interactive DVR with a new sag detection algorithm. The developed detection algorithm has a hybrid structure composed of an instantaneous detector and RMS-variation detectors. The source voltage passes through the sliding-window DFT and RMS calculator, and the instantaneous sag detector. If an instantaneous sag is detected, the RMS variation detector-1 is selected to calculate the RMS variation. The RMS variation detector-2 is selected when the instantaneous sag occurs under the operation of the RMS variation detector-1. The feasibility of the proposed algorithm is verified through computer simulations and experimental work with a prototype of a line-interactive DVR with a 3kVA rating. The line-interactive DVR with the proposed algorithm can compensate for an input voltage sag or an interruption within a 2ms delay. The developed DVR can effectively compensate for a voltage sag or interruption in sensitive loads, such as computers, communications equipment, and automation equipment.

• 전력전자학회논문지
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• 제15권4호
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• pp.327-334
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• 2010

본 논문에서는 새로운 quasi Z-소스 토폴로지의 동적전압보상기를 제안한다. 제안된 시스템은 quasi Z-소스 PWM 교류-교류 컨버터를 기반으로 하고 있으며, 입력단과 출력단은 공통 접지이고, 연속적인 입력전류 모드(CCM)로 동작하는 특징을 가지고 있다. 전원 전압의 sag와 swell을 검출하기 위하여, 피크치 전압 검출기법이 사용되었으며, 제안된 시스템의 동작 원리를 제시하고 회로 해석을 하였다. 제안된 시스템은 30% 전압 swell과 60%의 심한 전압 sag가 발생하여도 과전압과 부족전압에 대하여 순간적으로 보상을 하였으며, 부하전압을 정현파의 정격전압으로 유지할 수 있었다. PSIM 시뮬레이션과 실험결과를 통하여 본 연구의 타당성을 입증하였다.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.371-376
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• 2014

A novel three-phase hollow fiber liquid phase microextraction was developed for the determination of malachite green (MG) in environmental waters, which selected [BMIM][$PF_6$] mixed with 1% trioctylphosphine oxide (TOPO) as supported phase. Several parameters (accepter phase pH, sample pH, supported phase membrane, volume of accepter phase, salinity, extraction time) that could affect extraction performance were investigated. Under the optimal extraction conditions, the established approach showed excellent characters as: high enrichment factor (212), wide linear range ($0.20-100{\mu}gL^{-1}$), low detection limit ($0.01{\mu}gL^{-1}$), good reproducibility (RSD, 8.9%, n=5) and satisfactory recovery (84.0-106.2%). The method was applied to detect MG at Yangtze River and pond waters in Zhenjiang, Jiangsu province, and 4 sites among 15 sampling sites were found MG with the concentration of $1.73-11.06{\mu}gL^{-1}$, which confirmed that the proposed environmentally friendly method was simple and effective for monitoring MG in aquatic system.

• 전기학회논문지
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• 제62권7호
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• pp.950-955
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• 2013

This paper proposes a new low-cost current detection method to implement vector-controlled inverter of 3-phase induction motor or permanent-magnet synchronous motor using 2 shunt resistors instead of expensive Hall current sensors. The proposed method can detect perfect phase currents without current-immeasurable area in all operating conditions of motor. This method uses 2 shunt resistors in Hall current sensor positions conventionally used to detect phase currents. Therefore, it requires accurate analog differential amplifiers to detect voltages across shunt resistors at high electric potential to ground. We show the good solutions which are implemented by voltage-divider resistors networks and the instrumentation amplifiers using several Op Amps at cheap price. Computer simulations and experiments were performed to confirm the effectiveness of proposed method. These results show that proposed method can perfectly detect phase currents without current-immeasurable area in all operating conditions of motor.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.11-16
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• 2006

본 연구는 이종 접착 재질의 접착계면에서 미접착 결함을 검출하기 위한 새로운 시험 기법을 개발하기 위함이다. 접착계면과 미접착계면에서의 초음파 전달 현상을 이론적으로 해석하여 초음파 신호를 모델링하였고, 이론적 분석에 기초하여 미접착계면에서의 위상 반전 현상을 애용한 검사 방법을 FRP/고무 시편에 적용하였다. 정량적으로 결함의 최소 검출 능력을 평가하기 위하여 알루미늄/고무 시편에 평저공을 가공하여 제작하였고 일반적으로 사용하고 있는 펄스에코반사법과 새로운 시험 기법인 위상반전법을 상호 비교하였으며 이론적으로 예측한 초음파 신호와 실험에서 얻은 초음파 신호를 근거로 위상반전법으로 미접착 결함을 검출할 수 있다고 판단하였다.

• 제어로봇시스템학회논문지
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• 제20권4호
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• pp.408-413
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• 2014

In this paper, we propose a fault diagnosis method based on Park's Vector Approach using the Euler's theorem. If we interpreted it as Euler's theorem, it is possible to easily find the phase angle difference between the healthy condition and the fault condition. And, we analyzed the variation of the phase angle and performed the diagnostic method of the induction motor using feature vectors that were obtained by using a Fourier transform. The analysis of time and speed variation of the motor was performed and, as a result, we could find more soft variations than rough variations. In particular, the analysis of the distortion through each phase shows that two-turn and four-turn shorted motors are linearly separable. In this experiment, we know that the maximum breakdown threshold value for determining steady-state fault detection is 49.0788. Simulation and experimental results show the more detectable than conventional method.

• 한국추진공학회지
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• 제13권2호
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• pp.9-16
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• 2009

본 연구는 이종 접착 재질의 접착 계면에서 미접착 결함을 검출하기 위한 새로운 시험 기법을 개발하기 위함이다. 접착 계면과 미접착 계면에서의 초음파 전달 현상을 이론적으로 해석하여 초음파 신호를 모델링하였고, 이론적 분석에 기초하여 미접착 계면에서의 위상 반전 현상을 이용한 검사 방법을 FRP/고무 시편에 적용하였다. 정량적으로 결함의 최소 검출 능력을 평가하기 위하여 알루미늄/고무시편에 평저공을 가공하여 제작하였고 일반적으로 사용하고 있는 펄스에코반사법과 새로운 시험 기법인 위상반전법을 상호 비교하였으며 이론적으로 예측한 초음파 신호와 실험에서 얻은 초음파 신호를 근거로 위상반전법으로 미접착 결함을 검출할 수 있다고 판단하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.984-996
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• 2014

In this paper, optimal sensing time allocation for adaptive multiband spectrum sensing-transmission procedure is investigated. The sensing procedure consists of an exploration phase and a detection phase. We first formulate an optimization problem to maximize the throughput by designing not only the overall sensing time, but also the sensing time for every stage in the exploration and detection phases, while keeping the miss detection probability for each channel under a pre-defined threshold. Then, we transform the initial non-convex optimization problem into a convex bilevel optimization problem to make it mathematically tractable. Simulation results show that the optimized sensing time setting in this paper can provide a significant performance gain over the previous studies.

• 반도체디스플레이기술학회지
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• 제14권1호
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• pp.45-49
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• 2015

Process gases with vapor or liquid phase as well as gas phase may experience alteration in itself or be contaminated in the fluid pipe to the process chamber. And thus it result in as particles or defects on the substrates in semiconductor, LCD, LED manufacturing. Purifiers and filters are used for control of contamination. However, none of detection device is available in the delivery line. In this paper, we propose simple device with lighting and sensing in order to predict contamination of the fluid or the tube wall. For some general purpose gases, it showed constant voltage output regardless of the flow rates. But, the smoke and the moisture in the air lowered the figure due to its concentration. Numerical values for several solid and liquid media were obtained. And, the operating temperature tendency was investigated.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권7호
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• pp.335-342
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• 2005

This paper presents a circuit to generate the current reference signal for single-phase harmonic elemination systems. Some of conventional methods for the current reference signal generation based on neural network algorithms. It requires complex circuitry to implement. the simplest method is to use analog filters. but it is difficult to obtain good current reference signals. So, we propose the harmonic detection circuit using GIC(Generalized Impedance Converter) for the purpose of low cost ,simple circuitry and high performance, Simulation and experimental results verify that the proposed circuit has better harmonic detection performance than conventional circuit.