• Journal of the Korean Solar Energy Society
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• v.39 no.3
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• pp.81-89
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• 2019

Long-term solar irradiance data are required for reliable performance evaluation and feasibility analysis of solar photovoltaic systems. However, measurement data of the global horizontal irradiance (GHI) are only available for major cities in Korea. Neither the direct normal irradiance (DNI) nor the diffuse horizontal irradiance (DHI) are available, which are also needed to calculate the irradiance on the tilted surface of PV array. It is a simple approach to take advantage of the decomposition model that extracts DNI and DHI from GHI. In this study, we investigate variations of solar PV power estimation due to the choice of decomposition model. The GHI data from Korea Meteorological Administration (KMA) were used and different sets of typical meteorological year (TMY) data using some well-known decomposition models were generated. Then, power outputs with the different TMY data were calculated, and a variation of 3.7% was estimated due to the choice of decomposition model.

• Journal of IKEEE
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• v.23 no.1
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• pp.334-337
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• 2019

In response to the increasing demand for energy, research and development of next-generation energy is actively carried out around the world to replace fossil fuels. Among them, the specific gravity of solar power generation systems using infinity and pollution-free solar energy is increasing. However, solar power generation is so different from solar energy that it is difficult to provide stable power and the power production itself depends on the solar energy by region. To solve these problems in this paper, we have collected meteorological data such as actual regional solar irradiance, precipitation, temperature and humidity, and proposed a solar power output prediction system using logic-based fuzzy Neural Network.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.1
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• pp.28-36
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• 2023

Solar radiation that is measured at relatively small number of weather stations is one of key inputs to crop models for estimation of crop productivity. Solar radiation products derived from GK-2A and Himawari 8 satellite data have become available, which would allow for preparation of input data to crop models, especially for assessment of crop productivity under an agrivoltaic system where crop and power can be produced at the same time. The objective of this study was to compare the degree of agreement between the solar radiation products obtained from those satellite data. The sub hourly products for solar radiation were collected to prepare their daily summary for the period from May to October in 2020 during which both satellite products for solar radiation were available. Root mean square error (RMSE) and its normalized error (NRMSE) were determined for daily sum of solar radiation. The cumulative values of solar radiation for the study period were also compared to represent the impact of the errors for those products on crop growth simulations. It was found that the data product from the Himawari 8 satellite tended to have smaller values of RMSE and NRMSE than that from the GK-2A satellite. The Himawari 8 satellite product had smaller errors at a large number of weather stations when the cumulative solar radiation was compared with the measurements. This suggests that the use of Himawari 8 satellite products would cause less uncertainty than that of GK2-A products for estimation of crop yield. This merits further studies to apply the Himawari 8 satellites to estimation of solar power generation as well as crop yield under an agrivoltaic system.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.370-375
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• 2011

BIPV시스템 분야는 다른 PV 적용 기술 분야에 비해 빠르게 성장하고 있으나 소형 건축물 위주로 적용되었으며, 초고층 건축물과 같이 수직적으로 높은 건축물의 외부환경조건에 대응하기 위한 BIPV의 적용 방안은 현재까지 연구되어지지 않았다. 국내의 경우 선진국에 비해 초고층 건축물에 대한 BIPV시스템 적용기술은 아직 초기 연구단계에 불과하다. 초고층 건축물의 고유의 특징을 고려하여 초고층 건축물 파사드에 입사하는 일사량의 분포가 균일하지 않을 것이라고 예측하고 실측을 진행하였으며, 실측 결과의 분석을 통하여 초고층 건축물에서의 BIPV시스템 최적 설계방안을 제시하였다. 결론적으로 본 연구에서는 초고층 건축물의 외벽에 입사하는 일사량을 고려한 Unit형 BIPV설계 방안을 제시하였으며, 특히, 측정된 일사량 데이터를 활용하여 초고층 건축물에 적합한 인버터의 선정의 대안을 제시하였다.

• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.23-28
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• 2003

The purpose of this study is to procure basic data to be used for solar power plant and concentrating collector designs. Site elevation is one of the major factors which influences the incoming insolation to the earth surface. Because the nonpermanent gases such as ozone, water vapor are unmixed components of the atmosphere and their concentrations are the function of height, the site elevation effects the relative proportion of the atmospheric constituents. We have measured solar radiation on Jiri Mt. (1,400m) and in Gurye area(115m) at the near same latitude. These values were then compared to obtain their characteristics and to investigate the potential for the solar utilization for both high and low elevated areas. From the experimental results, we concluded that 1) Daily mean horizontal global radiation and normal beam radiation on Mt. Jiri are 9.5%, and 35.3% higher than Gurye area respectively for a clear day. 2) A significant difference in atmospheric clearness index is observed between Mt. Jiri and Gurye areas.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.24-26
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• 2018

본 논문은 일사량 변화 시, 최대 출력점을 추종하는 태양광 발전시스템의 동적 응답특성을 향상시키기 위해 가변 스텝 사이즈 기반의 P&O (perturb & observe) 알고리즘을 제안하였다. 제안된 기법은 일사량과 PV (photovoltaic) 전류 관계로부터 일사량 변화에 따른 최대 전력점 전류 $I_{MPP}$변화 특성을 이용하며, 새로운 I-V 곡선에서 PV 동작점을 최대 출력점으로 빠르게 이동시키는 고속모드와 정상상태 부근에서 정상상태 효율 향상을 위한 가변 스텝 모드로 구성된다. 시뮬레이션 및 실험을 통해 $500W/m^2$와 $1000W/m^2$ 일사량 증감 조건에서 제안된 MPPT(maximum power point tracking) 기법의 추종 성능을 검증하였으며, MPPT 주기가 2초이고 일사량 $500W/m^2$과 $1000W/m^2$ 증감을 할 때 추종시간은 약 30초 정도이며, 정상상태 PV 전압변동은 약 0.1V로써 일사량 변화 조건에서 제안된 MPPT 기법의 알고리즘 성능을 검증하였다.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.146-156
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• 2010

The objective of this study was to improve the accuracy of calculation and estimation of solar radiation and duration of sunshine, which are the most important variables of photovoltaic power generation in deciding the location of photovoltaic facilities efficiently. With increasing interest in new and renewable energies, research on solar energy is also being conducted actively, but there have not been many studies on the location of photovoltaic facilities. Thus, this study calculated solar duration and solar radiation based on geographical factors, which have the most significant effect on solar energy in GIS environment, and corrected the results of analysis using diffuse radiation. Moreover, we performed ordinary kriging, a spatial statistical analysis method, for estimating values for parts deviating from the spatial resolution of input data, and used variogram, which can determine the spatial interrelation and continuity of data, in order to estimate accurate values. In the course, we compared the values of variogram factors and estimates from applicable variogram models, and selected the model with the lowest error rate. This method is considered helpful to accurate decision making on the location of photovoltaic facilities.

• Solar Energy
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• v.11 no.3
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• pp.3-8
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• 1991

There are fifteen solar radiation measurement stations over the entire country in Korea. However, they are not capable of supplying reliable solar radiation data for remote areas including islands. The un-manned automated insolation measurement station is suitable for these areas due to the electric power shortage and the maintenance problems at these isolated areas. Our main aim in this work is to develop a solar radiation measurement system which collects and stores data by itself utilizing a PV module and a battery as power source for entire system irregardless of the environmental condition. A developed KIER's prototype system along with an independent HWS reference system has been installed at the designated remote island, Dok-do. Global solar radiation has been measured every hour for a 6-month period of time by both systems at this site. A comparison between the measured solar radiation data by each system indicates that there is an excellent agreement showing average 3.0% of an absolute error. It has been observed that the 8-month average global solar radiation was $2,330W/m^2$ day at this island. We came to the conservative conclusion that the developed KIER system is applicable for measuring solar radiation and for supplying reliable fundamental design data for solar energy utilization system at the remote areas.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.208-213
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• 2008

Since The measured solar radiation incident on tilted surfaces by all directions has been widely used as important solar radiation data in installing solar flat-plate collectors. To maximize the incident beam radiation, the slope, which is the angle between the plane of the surface in question and the horizontal, and the solar azimuth angles are needed for these solar thermal systems. This is because the performance of the solar thermal system is much affected by angle and direction of incident rays. Recognizing those factors mentioned above are of importance, actual experiment has been performed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. The results obtained in this research could be used in installing optimal solar flat-plate collectors.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1096-1097
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• 2015

Cascaded DC-DC컨버터 방식은 전체 모듈을 하나의 인버터로 제어하는 중압집중방식에 비하여 일사량 변화 및 부분 음영에 대하여 최대전력발전에 유리하다. 태양광발전시스템에서 똑같은 조건의 부분 음영이 발생하였을 때 중앙집중 인버터 방식에서는 부분 음영의 영향을 받는 모듈이 부하로 작용하여 최대전력점을 제대로 추정하지 못하는 반면 Cascaded DC-DC컨버터 방식은 일사량의 변화에도 최대전력추종을 하여 비교적 높은 효율로 발전을 할 수 있다. 본 논문에서는 태양광발전시스템에서 중앙집중 인버터 방식과 Cascaded DC-DC컨버터 방식에 부분 음영이 발생하지 않았을 때와 발생하였을 때의 발전량의 차이를 PSCAD/EMTDC를 통해 모의 분석하고, 실제 태양광발전시스템에 적용하여 비교 분석한다.