• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1290-1292
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• 2001

Photovoltaic(PV) power generation system has been extensively studied and watched with keen interest as a clean and renewable power source. On the other hand, because the output power of solar cell is not only unstable but uncontrollable, the maximum power point tracking(MPPT) control is still hot issue with the tracking failure left unsolved under the sudden fluctuation of irradiance. Hence, in this paper, we introduce the mechanism of the tracking failure under the fluctuation of irradiance, and show the simulation results using SPRW(simulation method for PV power generation system using real weather conditions).

• 전기학회논문지
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• 제65권11호
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• pp.1800-1805
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• 2016

The micro-grid designed as bipolar ${\pm}750V$ low-voltage DC power distribution system demonstrated by KEPRI, demands interconnection of a number of small decentralized power source including variable renewable generator. Therefore, variable researches for the influence of interconnection with the bipolar typed DC grid and these variable power sources are required for superior quality of power distribution. Renewable power generation simulators for the bipolar ${\pm}750V$ low-voltage DC power distribution system are necessary for such researches. In this paper, we carry out a research on the photovoltaic simulator that be actually able to interconnect with a bipolar ${\pm}750V$ low-voltage micro-grid. Simulator for this research is not only able to simulate photovoltaic generation according to weather informations and PV modules characteristics, but also contribute to stabilization of bipolar ${\pm}750V$ low-voltage of the system. Therefore, the simulator was designed to develop a system that can situationally respond to variable control algorithms such as the MPPT control, droop control, EMS power control, etc.

• 전기학회논문지
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• 제61권12호
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• pp.1791-1800
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• 2012

This paper presents effective design schemes for a photovoltaic (PV) and battery hybrid system that includes state-of-the-art technologies such as maximum power point tracking scheme for PV arrays, an effective charging/discharging circuit for batteries, and grid-interfacing power inverters. Compared to commonly-used PV systems, the proposed configuration has more flexibility and autonomy in controlling individual components of the PV-battery hybrid system. This paper also proposes an intelligent coordination scheme for the components of the PV-battery hybrid system to improve the efficiency of renewable energy resources and peak-load management. The proposed algorithm is based on a rule-based expert system that has excellent capability to optimize multi-objective functions. The proposed configuration and algorithms are investigated via switching-level simulation studies of the PV-battery hybrid system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.177-178
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• 2008

Recently, the concern of PV(Photovoltaic) systems has increased because of an environmental problem and limitation of fossil fuel. In this paper, distribution system of existing one-way power flow and distribution system generating bidirectional power flow analyze voltage variation at distribution system interconnected multiple PV systems. Also, we analyze a supply voltage range of distribution system using LDC and ULTC voltage regulation method by case study.

• 설비공학논문집
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• 제26권12호
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• pp.559-564
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• 2014

The development of photovoltaic-thermal (PVT) technology has been introduced in recent years specifically to increase PV efficiency. One of the characteristics of PV systems is that the electricity generation increases as the solar radiation increases whereas the efficiency decreases because of high surface temperatures. Using a photovoltaic-thermal system, the surface temperature can be decreased by capturing the excess heat and the efficiency can be increased due to these characteristics. In this paper, three cases are introduced : 1) PV_r as the reference case, 2) PVT_a, which uses air as a heat source, and 3) PVT_w, which uses water as a heat source. Experiments were performed, analyzed, and compared to examine the effect of the PVT type on the efficiency of the system. The results showed that ETC($%/^{\circ}C$) efficiency of the PVT cases was increased versus the reference case due to decreasing surface temperature. Total efficiencies, which are electrical efficiency and thermal efficiency, for each PVT are tested and found to be 12.22% for PV_r, 29.50% for PVT_a, and 68.74% for PVT_w.

• Advances in Energy Research
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• 제8권1호
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• pp.1-19
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• 2022

The application of Photovoltaic (PV) power in the building sector, is expanding as part of the ongoing energy transition into renewables. The article addresses the question of sustainability of energy generated from PVs through an environmental assessment of a building-integrated PV system (BIPV) connected to the grid through net metering. Employing retrospective life cycle analysis (LCA), with the CCaLC2 software and ecoinvent data, the article shows that the carrying structure and other balance of system (BOS) components are responsible for a three times higher energy payback time than the literature average. However, total environmental impact can be lowered through reuse or reinstallation of PVs on the same building structure after the 30-year interval. Further ways to improve environmental efficiency include identifying the most polluting materials for each LCA parameter. The results of this study are of interest to researchers and producers of PVs and organizations investing and promoting decentralized power production through PVs.

• 전력전자학회논문지
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• 제26권1호
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• pp.38-45
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• 2021

The photovoltaic module has the characteristic of changing its output characteristics depending on the amount of radiation and temperature, where the arrays that connect them in series and parallel also have the same characteristics. These characteristics require the MPPT technique to find the maximum power point. Existing P&O and IncCond cannot find the global maximum power point (GMPP) for partial shading. Moreover, in the case of Improved-GMPPT and Enhanced Search-Skip-Judge-GMPPT, GMPP due to partial shading can be found, but the variation in the open voltage during temperature fluctuations will affect the operation of the Skip and will not be able to perform accurate MPPT operation. In this study, we analyzed the correlation between voltage, current, and power under solar module and array conditions. We also proposed a technique to find the maximum power point even for temperature fluctuations using not only the amount of radiation but also the temperature coefficient. The proposed control technique was verified through simulations and experiments by constructing a 2.5 kW single-phase solar power generation system.

• 산업경영시스템학회지
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• 제43권2호
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• pp.1-13
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• 2020

There are several methods of peak-shaving, which reduces grid power demand, electricity bought from electricity utility, through lowering "demand spike" during On-Peak period. An optimization method using linear programming is proposed, which can be used to perform peak-shaving of grid power demand for grid-connected PV+ system. Proposed peak shaving method is based on the forecast data for electricity load and photovoltaic power generation. Results from proposed method are compared with those from On-Off and Real Time methods which do not need forecast data. The results also compared to those from ideal case, an optimization method which use measured data for forecast data, that is, error-free forecast data. To see the effects of forecast error 36 error scenarios are developed, which consider error types of forecast, nMAE (normalizes Mean Absolute Error) for photovoltaic power forecast and MAPE (Mean Absolute Percentage Error) for load demand forecast. And the effects of forecast error are investigated including critical error scenarios which provide worse results compared to those of other scenarios. It is shown that proposed peak shaving method are much better than On-Off and Real Time methods under almost all the scenario of forecast error. And it is also shown that the results from our method are not so bad compared to the ideal case using error-free forecast.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.189-192
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• 2008

본 논문에서는 태양광 발전시스템의 인버터 개발에 필요한 태양광 시뮬레이터를 개발하고자 한다. 태양광 시뮬레이터를 one-diode 등가회로를 기반으로 기존의 제품을 수치적으로 모델링하고, P-V특성곡선을 이용하여 인버터가 MPPT를 수행 할 최대값 및 최소값을 찾아서 파라메터를 설계하였다. 그리고 설계된 파라메터를 PSIM으로 검증하였으며, Matlab을 이용하여 주파수 분석을 수행하였다.

• Current Photovoltaic Research
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• 제7권4호
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• pp.111-120
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• 2019

The output power of a crystalline silicon (c-Si) photovoltaic (PV) module is not directly the sum of the powers of its unit cells. There are several losses and gain mechanisms that reduce the total output power when solar cells are encapsulated into solar modules. Theses factors are getting high attention as the high cell efficiency achievement become more complex and expensive. More research works are involved to minimize the "cell-to-module" (CTM) loss. Our paper is aimed to focus on electrical losses due to interconnection and mismatch loss at PV modules. Research study shows that among all reasons of PV module failure 40.7% fails at interconnection. The mismatch loss in modern PV modules is very low (nearly 0.1%) but still lacks in the approach that determines all the contributing factors in mismatch loss. This review paper is related to study of interconnection loss technologies and key factors contributing to mismatch loss during module fabrication. Also, the improved interconnection technologies, understanding the approaches to mitigate the mismatch loss factors are precisely described here. This research study will give the approach of mitigating the loss and enable improvement in reliability of PV modules.