• 대한전기학회논문지
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• 제36권2호
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• pp.107-113
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• 1987

A complete design of a new digital control circuit for a three-phase controlled rectifier is presented. The circuit consists of a gating signal generating ROM, down counter and adder. Proposed scheme is simple and quite adequate to the microprocessor-based digitally controlled systems. The basic principle and operation characteristics of the circuit are described and experimental-results show good dynamic performance. Synchronization problem with noisy reference is also discussed. The basic phylosophy developed can be extended to the other phase control system, e.g., cycloconverters, ac voltoge controllers, etc.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.64-67
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• 1987

We demonstrate the optical bistability and multistability using light emitting devices, a photodetector, and transistors under the positive electro optic feedback. Its operating principle and high speed operation Scheme are also described.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1235-1238
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• 2004

This paper presents the large-signal transient analysis of a self-driven active-clamp forward converter, eliminating the extra drive circuit for the active clamp switch. The operation principle of the converter was presented and experiential results were used to verify the analyzed results. A 50-W prototype converter built and tested it. From the tested results, input transient response and load transient response of the converter were established.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.147-149
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• 2007

A new half bridge converter without DC offset of magnetizing current is proposed. The proposed half bridge converter can realize no DC offset of magnetizing current as well as no circulating current, and guarantee ZVS operation. Therefore it has high efficiency and high power density, especially in wide input range. The operational principle, DC conversion ratio and ZVS analysis are presented. Experimental results demonstrate that the proposed converter can achieve a significant improvement in the efficiency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1160-1162
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• 2003

This paper presents ZVZCS(Zero-Voltage and Zero-Current Switching) Dual TTFC(Two-Transistor Forward Converter) without primary freewheeling diodes. The principle of operation, feature and design considerations are illustrated and verified through the ecperiment with a 1.8kW 55kHz MOSFET based experimental circuit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1163-1165
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• 2003

This paper presents the TTFC(Two Transistor Forward Converter) using Synchronous Rectifier. The principle of operation, feature ana design considerations are illustrated and verified through the experiment with a 200W 100kHz MOSFET based experimental circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.112-114
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• 2008

This paper proposes a new two-stage Z-source converter (TSZC). The purpose of the proposed system is to obtain the ac voltage with a maximum boost voltage for fuel cell applications as a renewable energy source. In order to provide a continuous current path, a switching strategy for the dc-ac ZSI and ac-ac ZSC of the proposed system was used. The operation principle, analysis and simulation results of 1.2 kW fuel cell stack were also presented.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.36-38
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• 1989

We have developed Magnetic Pulse Compression System to realize repetitive excimer laser excitation. The principle of this system is to use the large change in permiability owing to the nolinear characteristics of ferro-magnetic material (Metglas2605s-2 metal ribon). Prior to the laser operation, the MPC system was tested with a dummy load (5$\Omega$) and laser head. Laser head has a discharge volume of 1.0 (w) x 2.0 (h) x 20.0(1) cm. This MPC system compressed a 6.2us (FWHM), 80 A pulse into a 0.4us(FWHM), 1.3kA pulse.

• 센서학회지
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• 제33권2호
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• pp.63-69
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• 2024

A novel method for measuring hydrogen concentration is introduced, along with its working principle and a novel detection algorithm. This configuration requires no additional reference compartment for potentiometric electrochemical measurements; therefore, it is the most suitable for measuring dissolved hydrogen in the liquid phase. The sensor's electromotive force saturates at a certain point, depending on the hydrogen concentration during the heating process of the sensor operation. This dynamic temperature scanning method provides higher sensitivity than the constant temperature measurement method.

• Journal of Power Electronics
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• 제18권5호
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• pp.1545-1554
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• 2018

This paper proposes a modified control strategy to improve the performance of three-phase four-leg shunt active power filters (APFs) for the compensation of three phase unbalanced loads. Unbalanced current cannot be obtained accurately by a harmonic detector due to the lower frequency. The proposed control strategy eliminates conventional harmonic detectors by directly regulating the source current. Therefore, the computational complexity is greatly reduced and the performance of the APF is improved. A mathematic model has been developed based on the source currents. The corresponding controllers have been designed based on the sinusoidal internal model principle. The proposed control strategy can guarantee excellent compensation performance and stable operation after an extreme disturbance such as a short circuit fault. In addition, the proposed technique can selectively compensate specific harmonics. A 50kVA prototype APF is implemented in the laboratory to validate the feasibility and performance of the proposed control strategy.