• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.137-138
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• 2013

능동 클램프 포워드 컨버터의 2차단에 전류 증배 정류회로를 사용할 경우 2차단에서의 도통 손실을 줄일 수 있다. 뿐만 아니라 상대적으로 큰 자화 인덕턴스와 작은 누설 인덕턴스를 이용하여 영전압 스위칭을 달성할 수 있으므로 회로 전체 동작 측면에서 바람직하다. 본 논문에서는 제안된 회로의 동작 설명과 함께 영전압 스위칭을 위한 조건을 다루었고 240W급 (12-V/20-A) 프로토타입 회로를 통해 분석 결과의 타당성을 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.15-16
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• 2013

전기자동차용 급속 충전기에서 전력변환 효율은 절연형 DC-DC 컨버터에 의해 좌우된다. 이때 DC-DC 컨버터의 출력 전압 범위가 넓기 때문에 기존의 3레벨 컨버터를 사용할 경우 충전전압이 낮을 때 순환전류가 커지는 문제점이 있다. 본 논문에서는 넓은 충전전압범위를 갖는 전기자동차용 급속충전기를 위한 3레벨 DC-DC 컨버터의 하이브리드 스위칭 기법을 제안한다. 제안한 하이브리드 스위칭 기법은 충전전압이 낮을 때 순환전류를 줄일 수 있어 주로 낮은 배터리 전압에서 동작하는 CC충전 모드 시 도통 손실을 줄일 수 있다. 또한 커플인덕터를 사용하여 순환전류를 줄이고 Lagging Lag 스위치의 ZCS 턴오프를 성취시켜 손실을 줄일 수 있다. 기존의 스위칭 방법과 하이브리드 스위칭 기법에 따른 손실을 비교하여 제안한 스위칭 기법의 타당성을 검증하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.564-567
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• 2004

New address electrode having separated dual electrode is suggested to reduce addressing time in ac PDP. Addressing characteristics of suggested electrode has been investigated in the test panel with high Xe partial pressure. It has been found that both the formative and jitter width of the suggested electrode is improved by 10 -20 % over the wide range of address voltage level compared with the conventional one. The dynamic margin of the panel also greatly improved. The key feature behind this type of structure is that it can extend the controllability of the wall charge distribution during the reset and address discharge without significant increase in capacitive load of address electrode.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.91-94
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• 2004

We report on the opto-electronic properties of red, green, and blue poly (fluorene) co-polymer light-emitting devices (PLEDs) fabricated on a flexible plastic substrate. The plastic substrate used has a multi-layer structure with water vapor and oxygen transmission rates of less than $10^{-5}$ g/$cm^2$-day-atm and $10^{-7}$ cc/$cm^2$-day-atm, respectively. We obtained a wide range of color gamut and a maximum emission efficiency of 0.7, 10, and 1.7 cd/A for red, green, and blue PLEDs, respectively. Finally, a simple equivalent circuit model is proposed to simulate PLED current density-voltage characteristics.

• 전기의세계
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• 제18권4호
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• pp.7-15
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• 1969

In this method the condenser excite winding has the phase angle of 90 electrical degree, with the load winding in stator. The condenser excite wing is connected with the condenser while the load winding is with the full rectifer. Direct and quardrature axis components of rotating field winding are composed, of balanced two phase winding, and each one of them is connected with half wave rectifiers. Initically, small amount of lead current can be induced at the condenser excite winding by residual magnetism of rotor. The induced lead current forces the rotating field winding to be excited by synchronous alternating magnetic field. The speed electromotive force, there for, induced in rotating field winding shall electro magnetize the rotating field pole by rotating half wave rectifiers. In the case of the charging generator directly coupled with engines at the operation of wide range speed, the generated region, such as vehicles, aircraft, ships etc, is occured. In conclusion, we can take the advantage of, omitting of voltage regurator and current limiter for charging load and reducing the consumption of fuel using the generated region which can be devided in to Impossible generated region, Generated region, and suspension generated region.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.495-497
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• 1996

This paper proposes LCC type high frequency resonant inverter to be used as a source of induction heating device or ultrasonic device and considers of operating characteristic for it. The inverter is operated safely over wide range load, because it has both panel loaded capacitor and series loaded capacitor. Then, switching frequency of the inverter is controlled by feedback voltage and current in order to have constant output power even when load is varied.

• 조명전기설비학회논문지
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• 제14권6호
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• pp.12-17
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• 2000

IN induction heating system the high frequency operation allows a rapid response to current fluctuation in the inverter and result in improved welding quality. To work induction heating of nonferrous metals, a welding power supply is need high working frequency and high power. This paper is shown design technique for increasing working frequency in induction heating for welding coppers. A series-parallel resonate inverter consists of H-type bridges, each of whose arms is composed of a combination of two parallel IGBTs. Inverter operating with the fixed frequency is controlled by pulse width modulation (PWM). As switching adapted the Zero-Voltage Switching technique to reduce switching losses the system is high efficiency. The propose inverter has feature which is high efficiency for very wide load variations with a narrow range of duty cycle ratio control and load short circuit capability. Detailed experimental results obtained from a 48[V] output, 500[W] experimental inverter are presented to verify the concept.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.193-196
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• 2003

This paper describes a new Sag-Swell generator for the test of custom power devices such as UPS, DYR, DSTATCOM, 5575, etc. The proposed science has good features of simple structure, high reliability, wide range of Sag and Swell variation, and easy control. Outage, harmonic distortion, notches, and voltage unbalance also can be generated. The operation principle of the proposed scheme is described and verified through simulations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.370-374
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• 1991

This paper presents a static circuit model for static ant dynamic simulation of induction motors and identification of motor parameters. Instead of usual T-circuits, equivalent ${\pi}$-circuit has been proposed so that power Inputs into motor terminals can very easily calculated with very well known load flow method. It has been shown that, with wide range variation of applied voltage and frequency, successful static simulations can be performed and further the proposed static model can be used to simulate dynamic characteristics. Finally it is shown also that motor parameters can easily be identified based on the proposed static circuit.

• Journal of information and communication convergence engineering
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• 제14권2호
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• pp.122-128
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• 2016

In the future, hybrid power management systems using fuel cells (FCs) and batteries will be used as the driving power systems of ships. These systems consist of an FC, a converter, an inverter, and a battery. In general, an FC provides steady-state energy; a battery provides the dynamic energy in the start state of a ship for enabling a smooth operation, and provides or absorbs the peak or dynamic power when the load varies and the FC cannot respond immediately. The FC voltage range is very wide and depends on the load; Therefore, the FC cannot directly connect to the inverter. In this paper, we propose a power management strategy and design process involving a unidirectional converter, a bidirectional converter, and an inverter, considering the ship's operating conditions and the power conditions of the FC and the battery. The presented experimental results were verified through a simulation.