• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.293-296
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• 2001

A conventional power supply to drive a microwave oven has ferro-resonant transformer and high voltage capacitor(HVC). Though it is simple, transformer is bulky, heavy and has low-efficiency. To improve this defect, a high frequency inverter type power supply has been investigated and developed in recent years. But, because of additional control circuit and switching device, inverter-type power supply is more expensive than conventional one. In this study, The design procedure of a novel HVC embedded high frequency transformer is proposed for down-sizing and cost reduction of Inverter-type power supply. Also, equivalent circuit mode] is derived by FEM analysis and impedance measurements. And the operation of proposed HVC embedded transformer is verified by simulations and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.419-420
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• 2015

In this paper, a low-cost single-phase PWM rectifier with small DC-link capacitors is proposed, where a buck-boost converter with a low power rating is added at the DC link. By controlling the auxiliary circuit so as to absorb the voltage ripple in the DC link, the second-order voltage ripple in DC-link capacitor can be reduced significantly. Therefore, a small film capacitor can be utilized to replace the bulky electrolytic capacitors. The simulation results are shown to verify the validity of the proposed method.

• 전기학회논문지
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• 제66권6호
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• pp.981-987
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• 2017

In this paper, we describe the LPM structure with a two-phase, which is not used previously, and explain its operation principle. In order to predict the accurate performance of LPM reduction model, finite element model was derived and the back EMF of LPM reduction model was measured and compared. In order to investigate the thrust and normal force of the LPM reduction model, a driving circuit capable of applying two-phase pulse currents was constructed and the performance was predicted in conjunction with the finite element analysis model. Finally, the design considering actual LPM size was performed. Since the size of the reduction model is small, the field could be made of a permanent magnet. However, it is almost impossible to manufacture a permanent magnet to match the size and capacity of a real LPM for a vehicle, in terms of cost and writing. Therefore, the actual vehicle LPM was replaced by wound type that generates a magnetic field by applying current to the field winding, and the final model was derived using the reaction surface method.

• Journal of Power Electronics
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• 제6권2호
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• pp.139-145
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• 2006

This paper describes the ultra precise position estimation of a servomotor using a sinusoidal encoder based on Arcsine Interpolation Method for the cost reduction of circuit design. The amplitude and offset errors of the sinusoidal encoder output signals, from the encoder itself and analog signal processing procedures, are effectively compensated and on-line tuned by utilizing a low cost programmable differential amplifier without any special expensive equipment. For a theoretical evaluation of the practical resolution of this system, the relationship between the amplitude of ADC(Analog to Digital Converter) input signal errors and the anticipated resolution is also addressed. The performance of the proposed method is verified by comparing it with speed control characteristics of the servomotor driving system using a digital incremental 50,000ppr encoder in the experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.1-6
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• 2001

In this article, the fundamental concept, characteristics and application potentials of coreless printed-circuit-board (PCB) transformers are described. Coreless PCB transformers do not have the limitations associated with magnetic cores, such as the frequency limitation, magnetic saturation and core losses. In addition, they eliminate the manual winding process and its associated problems, including labor cost, reliability problems and difficulties in ensuring transformer quality in the manufacturing process. The parameters of the printed windings can be precisely controlled in modern PCB technology. Because of the drastic reduction in the vertical dimension, coreless PCB transformers can achieve high power density and are suitable for applications in which stringent height requirements for the circuits have to be met. A transformer's power density of $24W/cm^2$ has been reported in a power conversion application. When used in an isolation amplifier application, coreless PCB transformers tested so far enable the amplifier to achieve a remarkable linear frequency range of 1MHz, which is almost eight times higher than the frequency range of 120kHz in existing Integrated-Circuit products. PCB materials offer extremely high isolation voltage, typically from 15kV to 40kV, which is higher than many other isolation means such as optocouplers. It is envisaged that coreless PCB transformers can replace traditional core-based transformers in some industrial applications. Their application potentials deserve more attention and exploration.

• 대한전자공학회논문지SD
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• 제41권5호
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• pp.51-60
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• 2004

반도체 기술의 발달로 회로의 집적도와 복잡도가 증가함에 따라 칩의 생산 과정에서 고장이 발생하는 빈도가 높아지게 되었다. 칩의 수율을 향상시키고, 생산 단가를 절감시키기 위해서 고장의 원인을 찾아내고 분석하는 과정은 매우 중요하다. 그러나 고장의 원인을 분석하는 과정 중 고장의 위치를 찾아내는 데는 많은 시간이 소요된다. 게이트 수준에서의 고장 위치 진단은 물리적 수준에서의 고장 범위를 한정해 줌으로써 고장 위치를 찾는 데 소요되는 시간을 줄 일 수 있다는 데 의미를 갖는다. 본 논문에서는 새로운 방식의 고장 딕션너리 방식과 추가적인 고장 시뮬레이션 방식을 혼합하여, 메모리의 소비를 최소화하면서도 시뮬레이션 수행 시간을 단축시킴으로써 효과적으로 고장 진단을 수행할 수 있는 고장 진단 알고리듬을 제안한다.

• 한국산학기술학회논문지
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• 제12권6호
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• pp.2707-2712
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• 2011

본 논문에서는 400V, 120W 급 LED 구동을 위한 1단 전류 경계모드(Boundary Condition Mode) 제어방식의 역률 개선 제어회로를 설계하였다. 제안하는 제어회로는 역률 개선 및 고조파 발생을 감소시키는 기능을 가지고 있으며, 또한 PFC(Power Factor Correction)회로 내에서 상대적으로 많은 면적을 차지하는 기존의 바이폴라 트랜지스터 구조 대신 새로운 CMOS 회로로 설계하였다. 기존대비, 약 30% 정도의 레이아웃 면적을 줄이게 되었고, 상용화 시 칩의 가격 경쟁력이 클 것으로 사료된다.

• 센서학회지
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• 제28권2호
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• pp.133-138
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• 2019

The a-InGaZnO (a-IGZO) thin film transistor (TFT) has the advantages of larger mobility than that of amorphous silicon TFTs, acceptable reliability and uniformity over a large area, and low process cost. A capacitive-type touch sensor was studied with an a-IGZO TFT that can be used on the front side of a display due to its transparency. A capacitive sensor detects changes of capacitance between the surface of the finger and the sensor electrode. The capacitance varies according to the distance between the sensor plate and the touching or non-touching of the sensing electrode. A capacitive touch sensor using only one a-IGZO TFT was developed with the reduction of two bus lines, which made it easy to reduce the pixel pitch. The proposed sensor circuit maintained the amplification performance, which was investigated for various drive conditions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1891-1895
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• 2003

Switch-mode power supplies (SMPS) have become a major source of conducted electromagnetic interference (EMI) which is the combination between differential mode (DM) noise and common mode (CM) noise. This paper presents the conducted EMI reduction approach in flyback switched mode power supply by rerouting for circuit balance to reduce common mode noise. And differential mode noise can be reduce by adding $c_x$ capacitor across the input power line, and passive element to the gate drive of switching device MOSFET to slow down the switching times. This combination of our approach is the effective way to reduce the conducted EMI and it is also a cost effective for product design

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.254-255
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• 2013

In this paper, four switches three-phase Z-source dynamic harmonic filter is proposed. It has many advantages, such as reduction of the cost, switching loss and smaller drive circuit. In order to reduction harmonics, new PWM modulation technique with a variable index has been suggested that in comparison with a fixed index type has more capability. The paper presents an application of direct current control(DCC) method in Z-source dynamic harmonic filter to reduce the harmonics generated by the non-linear load. The experimental results will verify the validity of the proposed method.