• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2012년도 추계학술대회 논문집
• /
• pp.85-87
• /
• 2012

This paper describes the design and analysis of an integrated transformer magnetic core which comprises of two different power cores with PFC inductor and LLC resonant transformer magnetic cores. The equivalent magnetic circuit modeling approach is employed to analyze the variations in coupling coefficient and inductance in terms of air gaps under the operations of the respective power core. Simulation and experimental studies are performed with a fabricated prototype integrated core and their results are discussed.

• Journal of Magnetics
• /
• 제22권2호
• /
• pp.196-202
• /
• 2017

The occurrence of ferroresonance in electrical systems including nonlinear inductors such as transformers will bring a lot of malicious damages. The intense ferromagnetic saturation of the iron core is the most influential factor in ferroresonance that makes nonsinusoidal current and voltage. So the nonlinear behavior modeling of the magnetic core is the most important challenge in the study of ferroresonance. In this paper, the ferroresonance phenomenon is investigated in a single phase transformer using the finite element method and considering the hysteresis loop. Jiles-Atherton (JA) inverse vector model is used for modeling the hysteresis loop, which provides the accurate nonlinear model of the transformer core. The steady-state analysis of ferroresonance is done while considering different capacitors in series with the no-load transformer. The accurate results from copper losses and iron losses are extracted as the most important specifications of transformers. The validity of the simulation results is confirmed by the corresponding experimental measurements.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2022년도 춘계학술발표대회
• /
• pp.464-467
• /
• 2022

기업의 사회적 책임에 대한 요구가 높아짐에 따라 기업의 지속 가능 경영 보고서 발간은 증가 추세를 보이고 있다. 그러나 이전까지의 연구는 지속가능성 및 기업의 재무적, 비재무적 연관성에 초점이 맞춰져 있었으며, 전통적인 토픽 모델링 기법만을 제한적으로 사용한다는 한계를 보였다. 본 연구에서는 Transformer 기반의 맥락을 고려한 토픽 모델링 기법을 도입하여 다양한 이해관계자 측면에서 이용 가능한 25 개의 주제를 도출하였다. 또한 동적 토픽 모델링(Dynamic Topic Modeling)을 통해 주제의 변화를 시계열적으로 파악했다.

• 한국산학기술학회논문지
• /
• 제7권3호
• /
• pp.350-357
• /
• 2006

본 논문에서는 압전 변압기와 CCFL의 전기적 등가회로에 의한 PSPICE 모델을 제시하였다. CCFL 모델은 최소 제곱근을 이용하여 모델의 파라미터들을 유도하였으며, 푸시풀 인버터로 구동되는 압전 변압기 및 CCFL을 PSPICE로 시뮬레이션하여 모델들을 해석하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
• /
• pp.97-100
• /
• 2007

There are regulations on each building for its classification and It is corresponding determined contract demand. For transformer's capability calculation algorithm, cumulated power information of each customer is used to analysis the correlation between power usage and Demand Rate. By modeling this using Least Square Method, it can be targeted to recognize the pattern of transformer use in the past and make a prediction on it in the future.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 학술대회 논문집 전문대학교육위원
• /
• pp.135-139
• /
• 2003

Presented on this paper are state of the art review of transformer protection technique, EMTP modeling, and comparative analysis of improved digital relaying algorithms for differential protection of large transformer.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
• /
• pp.9-12
• /
• 2000

This paper describes the modeling and experimental results of coreless printed circuit board (PCB) based transformer that can be used for power conversion at high frequency operation. The principle of using coreless PCB based transformer in 2MHz, 10W class ZVS Flyback DC-DC converter has been successfully demonstrated. The maximum power conversion efficiency is 79%. Even for high operating frequency, an efficiency greater than 70% can be obtained with under 1% regulation error.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
• /
• pp.524-527
• /
• 2003

This paper describes control of the grid connected transformer-less type photovoltaic(PV) power conditioning system. which is simpler and more efficient than conventional transformer type systems. With modeling and analysis of PV system, the validity of the control strategy was verified by simulations and experimental results.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 1993년도 추계학술발표회논문집
• /
• pp.103-106
• /
• 1993

This paper describes the modeling of winding vibration for a variation of load and temperature. The structural changes in transformer windings due to heat cause the change of vibration patterns. The vibration signals were detected by the accelerometer on the transformer windings. The real values were compared with estimated value using least-squares method, vibration model was cstablished and with this model, error compared with original signal was less than -50[db]. These results could be applied to diagnosis of incipient failures of the power transformers.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• 제5B권3호
• /
• pp.243-247
• /
• 2005

The Different-volume- V-connection transformer is known as an electric power source that can supply 3-phase electric power and single-phase electric power at the same time. Usually, we use two single-phase transformers that have different volumes. In this paper, we propose the use of a 3-phase 5-leg transformer with the different-volume- V-connection. And, we examine the magnetic properties of the 5-leg core model with the different-volume- V-connection. The magnetic properties of cores with the different-volume- V-connection are compared with those with the delta-connection. In order to express the magnetic anisotropy of the core materials and to calculate the iron loss directly, the two-dimensional vector magnetic property is considered with the E&SS modeling in the simulation.