• Journal of Power Electronics
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• 제9권6호
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• pp.903-910
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• 2009

In this paper, a digital average current mode control using diode current sensing technique is proposed. Although the conventional inductor current sensing technique is widely used, the sensed signal of the current is negative. As a result, it requires an additional circuit to be applied to general digital controller ICs. The proposed diode current sensing method not only minimizes the peripheral circuit around the digital IC but also consumes less power to sense current information than the inductor current sensing method. The feasibility of the proposed technique is verified by experiments using a 500W power factor correction (PFC) boost rectifier.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권2호
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• pp.39-52
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• 2003

This paper deals with an automatic design procedure for the maximum torque density and power factor in a synchronous reluctance motor (SynRM). The focus of this paper is the design relative to the number of flux barrier and the ratio Kw of flux barrier width to iron sheet width of a SynRM under the mechanical constraint. The Finite Elements Analysis (FEA) has been used to evaluate the maximum torque density and power factor with each rotor shape. The proposed procedure allows to define the rotor geometric dimensions starling from an existing mootor or a preliminary design. The maximum torque density and power factor of a SynRM has been resulted with the rotor design variation. To prove the propriety of the designed SynRM, the Digital Signal Processor (DSP) installed experimental devices are equipped and the efficiency characteristic test is Performed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.781-783
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• 1999

A storage or transmission of image is difficult without image compression processing because the numbers of generated or reborned image data are very much. In case of the random signal, image compression efficiency is low doing without loss of image information, but compressibility by using JPEG is better. We used Huffman code of JPEG, it assigne the low bit value for data of a lot of generated frequency, assigne the high bit value for data of a small quantity. This paper improved image compression efficiency with transformming Q-factor and certified the results with compressed image. A proposed method is very efficience for continuos a color tone image.

• 대한전기학회논문지:전력기술부문A
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• 제49권10호
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• pp.486-493
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• 2000

This paper presents an application to a multimachine power system of power system stabilizer using revised pole shift adaptive algorithm. Controller parameters are determined by using adaptive control theory in order to maintain optimal operation of generator under the various operating conditions. To determine the optimal parameters of controller and overcome the problem of pole placement algorithm, this paper presents pole shift algorithm revised pole shift factor. Also, the difference between the speed deviation with weighted factor and voltage deviation is used as the input signal of adaptive controller, which provides good damping characteristics. The results tested on a multimachine power system verify that the proposed controller has better dynamic and transient performance than conventional controller.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1030-1033
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• 2002

This paper, a new simple controller operates in continuous conduction mode (CCM) for Boost power factor collection converter is introduced. The duty ratios are obtained by comparisons of a sensed signal from inductor current and a negative ramp carrier waveform in each switching period. By using the proposed controller, input voltage sensing, error amplifier in the current feedback loop, and analog multiplier／divider are not required, then, the control circuit implementation is very simple. To verify the proposed controller, the circuit simulation for Boost power factor correction converter was applied. For the results, the input current waveform was shaped to be closely sinusoidal, implying low THD.

• 대한기계학회논문집A
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• 제20권10호
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• pp.3224-3233
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• 1996

SPATE(Stress Pattern Analysis by Thermal Emission) can be effectively used to analyze the stress distribution of the orthotropic structure under the repeated load by non-contact. In this research, the measuring conception and method of stress intensity factor of orthotropic material using SPATE are suggested. The relationships between the maximum values of SPATE signal and $1/\sqrt{X'}$ (or $1/\sqrt{y'}$) are theoretically established in the vicinity of crack tip of the orthotropic material. It is certified through SPATE experiment that their linear quality is very excellent.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.85-89
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• 2003

Many single-stage PFC(power-facto.-correction) ACHC converters suffer from the high link voltage at high input voltage and light load condition. In this paper, to suppress the link voltage, a novel high power factor high efficiency PFC AC/DC converter is proposed using the single controller which generates two gate signals so that one of them is used far gate signal of the flyback DC/DC converter switch and the other is applied to the Boost PFC stage. A 130w prototype for LCD monitor adapter with universal input $(90-265V_{rms})$ and 19.5V 6.7A output is implemented to verify the operational principles and performances. The experimental results show that the maximum link voltage stress is about 450V at 270Vac input voltage. Moreover, efficiency and power factor are over $84\%$ and 0.95, respectively, under the full load condition.

• 한국전자파학회논문지
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• 제8권6호
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• pp.551-557
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• 1997

이동통신에 있어서 안테나 높이에 대한 이득은 6 dB / octave로 잘 알려져 있다. 그러나 이동통신의 전파환경은 단순하지 않고 지형지물에 따라서 변하기 때문에 안테나 높이에 대한 이득도 전파환경에 따라서 달라칠 수 있다. 이 논문은 도심지 마이크로셀 환경에서의 기지국 안테나 높이 변화에 따른 수선전력의 변화를 평탄지형과 경 사지형을 모텔로하여 이론적으로 해석한 것이다. 또한 안테나 높이 이득이 나타나기 시작하는 거리인 이득점을 사률레이션에 의해 설험적으로 구하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제24권4호
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• pp.405-413
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• 2000

This paper present study on the application of sound pressure and vibration signals to detect the presence of defects in a rolling element bearing using a statistical analysis method. The well established statistical parameters such as the crest factor and the distribution of moments including kurtosis and skew are utilized in this study. In addition, other statistical parameters derived from the beta distribution function are also used. A comparison study on the performance of the different types of parameter used is also performed. The statistical analysis is used because of its simplicity and quick computation. Under ideal conditions, the statistical method can be used to identify the different types of defect present in the bearing. In addition, the results also reveal that there is no significant advantages in using the beta function parameters when compared to using kurtosis and the crest factor for detecting and identifying defects in rolling element bearings from both sound and vibration signals.

• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.951-958
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• 2013

This paper proposes the controller design for a stability improvement of an on-board battery charger. The system is comprised of a power factor correction (PFC) circuit and phase shift full-bridge DC-DC converter. The PFC circuit performs the control of the DC-link voltage and the input power factor. The DC-DC converter regulates the voltage and the current in the battery using the DC-link voltage. This paper proposes the design method of PI controller for the PFC circuit using a small signal model. The analysis and design of a type-three controller for the DC-DC converter is also presented. A simulation and experiment has been performed on the on-board battery charger and their results are presented to verify the validity of the proposed system.