• 한국재료학회지
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• 제32권7호
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• pp.320-325
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• 2022

Single OLED and tandem OLED was manufactured to analyze the electroluminescence characteristics of DC driving, AC driving, and full-wave rectification driving. The threshold voltage of OLED was the highest in DC driving, and the lowest in full-wave rectification driving due to an improvement of current injection characteristics. The luminance at a driving voltage lower than 10.5 V (8,534 cd/m²) of single OLED and 20 V (7,377 cd/m²) of a tandem OLED showed that the full-wave rectification drive is higher than that of DC drive. The luminous efficiency of OLED is higher in full-wave rectification driving than in DC driving at low voltage, but decrease at high voltage. The full-wave rectification power source may obtain higher current density, higher luminance, and higher current efficiency than the AC power source. In addition, it was confirmed that the characteristics of AC driving and full-wave rectification driving can be predicted from DC driving characteristics by comparing the measured values and calculated values of AC driving and full-wave rectification driving emission characteristics. From the above results, it can be seen that OLED lighting with improved electroluminescence characteristics compared to DC driving is possible using full-wave rectification driving and tandem OLED.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.265-267
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• 1995

A voltage source PWM converter with battery charging and AC/DC power conversion ability is proposed in this paper. The proposed voltage source PWM converter is independently controlled by active and reactive components and implemented by DSP controller. In UPS application the mathematical model of the voltage source PWM converter has been derived. Finally, the performance of the voltage source converter is shown and discussed through experimental results.

• Journal of Power Electronics
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• 제9권3호
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• pp.335-342
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• 2009

The Z-source inverter (ZSI) provides unique features such as the ability to boost dc voltage with a single stage simple structure. Although the dc capacitor voltage can be boosted by a shoot-through state, the voltage stress across the switching devices is rapidly increased, so high switching device power is required at the ZSI. In this paper, algorithms for minimizing the voltage stress are suggested. The possible operating region for obtaining a desired ac output voltage according to both the shoot-through time and active state time is investigated. The reference capacitor voltages are derived for minimizing the voltage stress at any desired ac output voltage by considering the dc input voltage. The proposed methods are carried out through the simulation studies and experiments with 32-bit DSP.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.17-18
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• 2000

A low-power source driver for TFT-LCDs has been proposed using the triple charge sharing method that enhances the AC power saving efficiency of the prior charge sharing method. The AC power saving efficiency of the proposed source driver reaches 66.6%. In addition, a novel OP-AMP with low-quiescent current has been developed. The measured quiescent current of the OP-AMP is $5{\mu}A{\sim}7{\mu}A$ at VDD=5V and VSS=0V with load resistance of $2k{\Omega}$ and load capacitance of 300pF.

• 전력전자학회논문지
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• 제11권5호
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• pp.480-488
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• 2006

최근 들어 컴퓨터, 전산 및 네트워크 설비, 전력변환장치, 에너지 절약장치 등에 의한 고조파의 발생으로 인해 전기의 품질이 저하되고 OA기기, FA기기, 정보통신기기 등을 포함한 전기설비의 동작에 악영향을 미치게 된다. 지금까지 이러한 고조파 관련 연구는 진단 및 대책기술개발에 관한 연구가 주를 이루고 있고 전기를 사용하는 수용가에서 발생하는 전기사고 중 고조파에 의한 사고의 원인규명은 대부분이 추측에 의한 것이지 실험 데이터를 활용한 정확한 원인 규명은 거의 이루어지지 않고 있다. 따라서, 국내의 실정에 맞는 고조파에 의한 오동작의 원인 규명에 필수적인 실험 데이터 자료를 위한 고조파 전원 발생장치의 개발은 필수적이라 할 수 있다. 본 논문에서는 고조파로 인한 사고의 특성을 분석하기 위해 고조파를 발생하고 합성할 수 있는 5[kVA]급 전원왜형장치의 구현에 대한 제반 사항을 연구하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.223-226
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• 2004

MgO thin films were deposited bye-beam evaporation on $SiO_2$/Si wafers for the application of a protective layer in alternating current plasma display panels (AC-PDPs). Three different MgO sources, single crystal, melted polycrystal and sintered polycrystal, were used to find out the change of the properties of MgO protective layer depending on the source type. The properties of MgO thin films such as density, orientation and surface morphology were influenced by the source type. MgO thin films deposited with the melted polycrystal source had the highest density with the highest (100) preferred orientation, whereas the films deposited with the sintered polycrystal source had the lowest density with less preferred orientation. Such a result seems to be originated from the different mobility of adatoms on the surface of the deposited MgO thin films. Different microstructures of MgO thin films deposited even in the same deposition condition were observed depending on the MgO source type, resulting in different discharge characteristics.

• Journal of Power Electronics
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• 제12권2호
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• pp.276-284
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• 2012

AC/AC power conversion is widely used to feed AC loads with a variable voltage and/or a variable frequency from a constant voltage constant frequency power grid or to connect critical loads to an unreliable power supply while delivering a very balanced and accurate sinusoidal voltage system of constant amplitude and frequency. The load specifications will clearly impose the requirements for the inverter stage of the power converter, while wider ranges of choices are available for the rectifier. This paper investigates the utilization of a buck-type current source rectifier as the active front-end stage of an AC/AC converter for applications that require an adjustable DC-link voltage as well as elimination of the low-frequency common mode voltage. The proposed solution is to utilize a combination of two or more zero current vectors in the Space Vector Modulation (SVM) technique for Current Sources Rectifiers (CSR).

• 한국산학기술학회논문지
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• 제7권6호
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• pp.1072-1077
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• 2006

본 논문은 AC 라인 리액터와 2개의 4레그 PWM 전압형 컨버터를 사용하여 병렬 및 직렬 능동필터 기능을 가지는 새로운 3상 Line-Interactive UPS 시스템을 제안하고 전압제어 방식을 설명한다. 제안하는 UPS 시스템의 병렬 및 직렬 PWM 전압형 컨버터에서 전압제어의 목적은 정상상태 및 과도상태에서 만족스러운 동작 특성을 보장하는 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.695-697
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• 1993

In this paper, a novel concept for a static three-phase to three-phase power converter for an AC drive with an unity power factor and reduced harmonics on the utility line is presented. The power circuit consists of two back-to-back connected six-pulse bridges having only a $5{\mu}F$ ceramic capacitor in the DC link. By controlling the active power balance between two bridges, the DC link voltage can be maintained within 20V deviation from the nominal value with the small ceramic capacitor regardless of the load variation even in the unbalanced source condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1364-1367
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• 2005

In this paper, a novel prototype topology of soft switching PWM controlled high frequency AC power conversion circuit without DC voltage smoothing chemical capacitor filter link from the voltage grid of utility frequency AC power supply source with 60Hz-100V or 60Hz-200V is proposed and introduced for innovative consumer induction heating(IH) boiler applications as hot water producer, steamer and super heated vapor steamer.