• 전력전자학회논문지
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• 제6권4호
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• pp.307-316
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• 2001

본 논문에서는 직류 특성과 절전 모드에서 비절전 모드 변환과 같은 부하 변동 시의 동특성을 동시에 개선할 수 있는 가중치 전압 제어를 적용한 PC 전원용 다중출력 포워드 컨버터를 설계하였다. 기생성분을 포함한 전력회로를 모델링하고 소신호 해석하였으며, 가중치 결정 방법과 전압 보상회로 설계 방법을 제시하였다. SABER 시뮬레이션과 실험을 통해 제안한 방법이 PC 전원의 직류 특성과 동특성을 향상시킴을 입증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2691-2694
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• 1999

The multi-resonant converter(MRC) can reduce the switching losses exiting in a converter, so it is capable of operating at a high frequency. Such a few MHz high frequency application provides a high power density [$W/inch^{3}$]. But the high voltage stress across a switch of the resonant circuit is about 4$\sim$5 times the input voltage, it causes increasing of the conduction loss in MRC. In this paper, the mode analysis for the suggested AT Forward MRC with low voltage stress is discussed. The operational modes of the AT Forward MRC are divided to 8 equivalent modes according to the two switching sequences, Each mode is analyzed over all of the paper.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.1051-1055
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• 1998

To achieve high efficiency in high power and high frequency applications, reduction of switching losses and noise is very important. In this paper, an improved zero voltage switching forward dc/dc converter is proposed. The proposed converter is constructed by using energy recovery snubbers in parallel with the main switches and output diodes of the conventional forward dc/dc converter. Due to the use of the energy recovery snubbers in the primary and secondary side, the proposed converter achieves zero-voltage-switching turn-off without switching losses for switching devices and output rectification diodes. The complete operating principles and experimental results will be presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.13-14
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• 2010

The active clamp forward converter provides zero voltage switching and low voltage stress in wide input voltage range. It has a high efficiency at a high switching frequency and the clamped energy is recovered to the input stage. It is available for the power adaptor circuit of notebook computer. The adaptor with 19.5V/200W output power is designed for notebook computer. Specially, it is considered the transformer properties of the converter in design process. The organized process is checked by the validity from the test of the active clamp forward converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.228-229
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• 2010

This paper presents an active voltage balancing approach using a forward fly-back power converter. In the proposed balancing scheme, cell with the higher voltage is selected to extract the extra energy and then a proportion of this extracted energy is distributed to other supercapacitors via the proposed circuit. A system structure consisting of five supercapacitors is built up to verify operation of the proposed scheme.

• 한국전기전자재료학회논문지
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• 제17권10호
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• pp.1034-1040
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• 2004

The latch-up current and switching characteristics of MOS-Controlled Thyristor(MCT) are studied with variation of the channel length and impurity concentration. The proposed MCT power device has the lateral structure and P-epitaxial layer in substrate. Two dimensional MEDICI simulator is used to study the latch-up current and forward voltage-drop from the characteristics of I-V and the switching characteristics with variation of impurity concentration. The channel length and impurity concentration of the proposed MCT power device show the strong affect on the anode current and turn-off time. The increase of impurity concentration in P and N channels is found to give the increase of latch-up current and forward voltage-drop.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.559-562
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• 2000

The problem of noise generation due to PWM switched-mode power converter has been widely noticed from the viewpoint of Electromagnetic Interference(EMI). Many kings of topologies for resonant converters have been developed both to overcome this noise problem and to attain high power efficiency. It is reported in references that resonant converters which are derived from PWM converter using resonant switch show much lower noise characteristics than PWM converter, and that current-mode resonant converter is more sensitive to stored charge in rectifying diode than voltage-mode counterpart concerning surge generation at diode’s turn-off. On the other hand, above mentioned resonant converters have defect of high-voltage stress on semiconductor switch and complicated circuit configuration. Hence, the simplified Forward-type resonant converter has been proposed and investigated due to its prominent features of simplicity of circuit configuration, low voltage stress and high stability. However, its noise characteristics still remain unknown. The purpose of this paper is to study quantitatively the noise characteristics of this simplified Forward-type resonant converter by experiment and analysis. The influence of parasitic elements and stored charge in rectifying diode on noise generation has been clarified.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.188-189
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• 2007

Conventional active-clamp forward converter shows good performance in low power applications, however it suffers from a high voltage stress of switch and is not suitable for high input voltage applications. To solve this problem, a new multi-level active-clamp forward converter is proposed in this paper. Utilizing low rating switches, the proposed converter features high efficiency and low cost promising for high input voltage applications.

• 전력전자학회논문지
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• 제23권6호
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• pp.373-380
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• 2018

This study proposes a new islanding detection method that uses the phase shift of feed-forward voltage and evaluates the performance of an existing method and the proposed method when the grid frequency changes within the allowable range under steady-state conditions. The investigated existing method, which is slip mode frequency shift (SMS), uses current phase shift to detect islanding. The SMS method supplies reactive current to the grid under this condition, but the proposed method does not generate additional reactive power because it does not depend on the current control loop. The performance in steady-state grid condition is evaluated through simulations and experiments.

• 한국전기전자재료학회논문지
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• 제15권3호
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• pp.201-207
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• 2002

In this paper, we haute proposed a novel trench electrode Base Resistance Thyristor(BRT) and trench electrode BRT with a intrinsic region. New power BRTs have shown superior electrical characteristics including the snab-back effect and the forward blocking voltage more than the conventional BRT. Especially, the trench electrode BRT with the intrinsic region has obtained high blocking voltage of 1600V. The blocking voltage of conventional BRT is about 400V at the same size. Because the breakdown mechanism of the BRT is the avalanch breakdown by impact ionization, the trench electrode BRT with intrinsic region has suppressed impact ionization, effectively. If we use this principle, we can develop a super high voltage power device and it applies to another power device including IGBT, EST and etc.