• 전력전자학회논문지
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• 제25권2호
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• pp.94-102
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• 2020

Considering that the output voltage and current of a single PV panel are limited in PV power generation, a PV array should be constructed by connecting several PV panels in series and parallel to meet the required voltage/power levels for power generation capacity. When a PV array is partially shaded, the maximum power generation depends on the configuration of a PV array and the presence or absence of blocking diodes. This study considers six PV array configurations and the presence or absence of blocking diodes. An optimum connection structure was proposed to maximize power generation in a partial shadow condition. Results were verified through simulation and an experiment.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 공동학술대회
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• pp.467-470
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• 2009

외부적으로 직렬 및 병렬로 접속된 50개의 DSSC로써 새로운 8 V DC 전원을 만들었다. 한 개의 DSSC는 $5.2{\times}2.6$ cm(유효면적 8 $cm^2$) 약 4.2%의 효율을 보이며, 전기화학적 임피던스 분석법 및 I-V 곡선으로 특성이 분석되었다. 또한 펄스형 Nd:YAG 레이저 빔을 활용하여 투명 도전층을 식각함으로써, 최종효율 약 45%를 달성하였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.229-230
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• 2007

We investigated the quench characteristics of a superconducting element, two superconducting elements in order to increase the current capacity of flux lock type SFCL. The flux-lock type SFCL consisted of the transformer with a primary winding and a secondary winding connected in parallel, and the superconducting element was connected with secondary winding in series. The applied voltage at that time was 160 ${\sqrt{3}}$. We found that the parallel connection between the superconducting elements increased the power capacity and let quench characteristics improve through their mutual linkage.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.210-213
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• 1999

A battery is the device that transforms the chemical energy into the direct-current electrical energy directly without a mechanical process. Unit cells are connected in series to obtain the necessary voltage, while being connected in parallel to organize capacity for load current and to decrease the internal resistance for corresponding the sudden shift of the load current. The circular-current, however, could be occurred when the system is driven in parallel. As a result, the new batteries are heated by over-change and discharge, and the over charge current makes to increase the rust of the positive grid and consequently the shortened life of the new batteris would be shown. In this paper, the internal resistance of charge and discharge will be balanced, through inserting the resistance into the system by way of calculation of the changed amount of internal resistance.

• 전력전자학회논문지
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• 제16권5호
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• pp.415-429
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• 2011

본 연구에서는 출력이 직렬 연결된 단상 quasi Z-소스 AC-AC 컨버터를 제안하였다. 제안된 시스템은 단상quasi Z-소스 AC-AC 컨버터 2대의 입력 단을 병렬로 연결하고 출력 단을 직렬로 연결한 구조로 되어 있으며, 역상 모드와 동상 모드 별 전류 흐름과 출력전압의 형성 과정을 나타내었다. DSP로 제어되는 실험 시스템을 제작하여 PSIM시뮬레이션 결과와 비교 분석하였다. 그 결과 각 모드별로 듀티 비를 제어하여 원하는 출력 전압을 벅-부스트 할 수 있었다. 컨버터 1대가 단독으로 운전한 경우에 비하여, 각각의 모드에 대하여 부하 저항의 증가에 따른컨버터 효율과 입력 역률을 제안된 방법에 의하여 개선할 수 있었다. 또한 역상 모드의 경우, 일정 부하에서 컨버터의 효율과 입력 역률을 각각 10[%]와 35[%]정도 개선하였으며, 특히 부하 저항이 변동하는 과도상태에서도 일정한 출력 전압을 유지할 수 있었다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.432-434
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• 2006

We investigated the quench characteristics of a flux-lock type superconducting fault current limiter (SFCL) according to the number of the superconducting elements at the subtractive polarity winding of a transformer. The flux-lock type SFCL consists of the transformer with a primary winding and two secondary windings connected in parallel, and the superconducting element was connected with secondary winding in series, respectively. The applied voltage at that tin was 200V. when two superconducting elements of the secondary winding was connected in parallel, the peak lie current increased up to 99A, while that flowing in a superconducting element in conventional flux-lock type SFCL showed 50A under the same conditions, the impedance of secondary winding under the same situation showed the opposite behavior. This enabled the parallel structure to be easy to increase the capacity of power system, in the meantime, The quench between two superconducting elements in the SFCL with two secondary windings connected in parallel was achieved simultaneously. While the quench-starting point was slightly different in the SFCL with two superconducting elements connected in series. We found that the parallel connection between the secondary windings increased the power capacity and let quench characteristics improve through their mutual linkage.

• 한국수소및신에너지학회논문집
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• 제34권1호
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• pp.26-31
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• 2023

In this study, in order to propose a modular method for type IV high aspect ratio modular hydrogen storage vessel, a numerical analysis was conducted on the heat transfer behavior in series and parallel connection methods, and the differences according to each connection method were reviewed. Computational fluid dynamics software was used to check the internal temperature and pressure values of the hydrogen storage container under charging conditions. In terms of thermal safety when charging hydrogen gas, it was confirmed that the parallel modularization method was superior.

• Steel and Composite Structures
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• 제19권5호
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• pp.1145-1165
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• 2015

A behavior model for screw connections is developed to provide a better representation of the nonlinear response of thin steel plate shear walls (TSPSWs) with infill plates attached to the boundary frame members via self-drilling screws. This analytical representation is based on the load-bearing deformation relationship between the infill plate and the screw threads. The model can be easily implemented in strip models of TSPSWs where the tension field action of the infill plates is represented by a series of parallel discrete tension-only strips. Previously reported experimental results from tests of two different TSPSWs are used to provide experimental validation of the modeling approach. The beam-to-column connection behavior was also included in the analyses using a four parameter rotational spring model that was calibrated to a test of an identical frame as used for the TSPSW specimens but without the infill plates. The complete TSPSW models consisting of strips representing the infill plates, zero length elements representing the load-bearing deformation response of the screw connection at each end of the strips and the four parameter spring model at each beam-to-column connection are shown to have good agreement with the experimental results. The resulting models should enable design and analysis of TSPSWs for both new construction and retrofit of existing buildings.

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.351-358
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• 2006

In this paper, the electrical characteristics of the contactless transformer is presented using the conventional coupled inductor theory. Compared with the conventional transformer, the contactless transformer has a large airgap, long primary wire and multi-secondary wire. As such, the contactless transformer has a large leakage inductance, small magnetizing inductance and poor coupling coefficient. Therefore, large magnetizing currents flow through the entire primary system due to small magnetizing inductance, resulting in low overall system efficiency. In high power applications, the contactless transformer is so bulky and heavy that it needs to be split by some light and small transformers. So, the contactless transformer needs several small transformer modules that are connected in series or parallel to transfer the primary power to the secondary one. This paper shows the analysis and measurement results of each contactless transformer module and comparison results between the series- and parallel-connection of the contactless transformer. The results are verified on the simulation based on the theoretical analysis and the 30kW experimental prototype.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.296-297
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• 2005

We have investigated the quench performance of shunt reactors in the parallel connection of resistive type superconducting fault current limiter (SFCL) components based on YBCO films. To increase voltage rating, components are connected in series and to increase current level, they are connected in parallel. This method has cauesd the unbalanced quench between each components. To improve the problem, we have compared the quench properties between the current limiting components without and with shunt reactors connected in parallel. To improve the quench performance, across individual SFCL components connected the shunt reactor in parallel. The components with shunt reactors successfully produced simultaneous quench, resulting from the bypass of the fault current in the direction of the shunt reactor.