• 한국태양에너지학회 논문집
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• 제29권3호
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• pp.1-11
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• 2009

Heliostat sun tracking accuracy could be the most important requirement in solar thermal power plant, since it determines the overall efficiency of power plant. This study presents the effect of geometrical errors on the heliostat sun tracking performance. The geometrical errors considered here are the mirror canting error, encoder reference error, heliostat position error. pivot offset and tilt error, gear backlash and mass unbalanced effect error. We first investigate the effect of each individual geometrical error on the sun tracking accuracy. Then, the sun tracking error caused by the combination of individual geometrical error is computed and analyzed. The results obtained using the solar ray tracing technique shows that the sun tracking error due to the geometrical error is varying almost randomly. It also shows that the mirror canting error is the most significant error source, while the encoder reference error and gear backlash are second and the third dominant source of errors.

• 제어로봇시스템학회논문지
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• 제16권7호
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• pp.711-719
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• 2010

Heliostat, as a concentrator reflecting the incident solar energy to the receiver located at the tower, is the most important system in the tower-type solar thermal power plant, since it determines the efficiency and performance of solar thermal plower plant. Thus, a good sun tracking ability as well as its good optical property are required. In this paper, we propose a method to compensate the heliostat sun tracking error. We first model the sun tracking error, which could be measured using BCS (Beam Characterization System), by multilayered neural network. Then the extended Kalman filter was employed to train the neural network. Finally the model is used to compensate the sun tracking errors. Simulated result shows that the method proposed in this paper improve the heliostat sun tracking performance dramatically. It also shows that the training of neural network by the extended Kalman filter provides faster convergence property, more accurate estimation and higher measurement noise rejection ability compared with the other training methods like gradient descent method.

• 한국태양에너지학회 논문집
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• 제29권1호
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• pp.50-57
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• 2009

Heliostat in the tower type solar thermal power plant is a mirror system tracking the sun's movement to collect the solar energy and it is the most important subsystem determining the efficiency of solar thermal power plant. Thus a good performance of it, which is mostly the accurate sun tracking performance under the various hazardous operating condition, is required. Heliostat control system is a system to manage the heliostat sun tracking movement and other operations. It also communicates with the master controller through the heliostat filed control system to receive and send the informations required to operate the heliostat as a part of the solar thermal power plant. This study presents a heliostat control system designed and developed for the 1MW solar thermal power plant. We first define the functionality of heliostat control system. Then sun tracking controller as well as the sun tracking algorithm satisfying the required functionality have been developed. We tested the developed heliostat control system and it showed a good performance in regulation of heliostat motion and communication.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 추계학술대회
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• pp.450-453
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• 2017

본 논문은 FPGA를 이용해서 태양을 추적하는 시스템에 대해서 소개한다. 센서를 이용한 추적방법과 태양의 고도를 프로그래밍하여 추적하는 방법을 혼합한 방식인 혼합식 태양 추적 방식을 이용한다. 본 논문에서의 센서는 이미지센서, 광센서를 사용하고 시간에 따라 태양의 고도를 프로그래밍하고 동작 시간은 컴퓨터에서 하이퍼터미널을 통한 무선통신을 통해서 수신한다. 비교적 개발비용이 저렴하고 업데이트 가능한 FPGA를 사용하고, 양방향 추적식 및 혼합추적법을 사용하여 최대한의 에너지 발전효율을 갖는 태양추적시스템을 제안한다.

• 한국정보통신학회논문지
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• 제18권8호
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• pp.1847-1853
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• 2014

이동통신 시스템의 OFDMA 방식은 신호에 대한 PAPR(Peak to Average Power Ratio) 값의 증가를 가져왔다. 이동통신 시스템 전력 소모의 대부분을 차지하는 전력 증폭기에 대한 효율 개선은 매우 중요한 핵심 기술이다. 전력 증폭기의 선형 특성 개선을 위해 디지털전치왜곡 기술을 사용하였으며, 전력 증폭기의 효율 개선을 위해 비대칭 도허티(Asymmetric Doherty) 방식을 사용하였다. 본 논문에서는 기존 비대칭 도허티 구조와 다른 새로운 구조의 비대칭 도허티 구조를 제안하였다. 제안하는 새로운 구조의 비대칭 도허티 방식에서는 전력 증폭기 구동단을 주경로와 첨두경로로 분리하였으며, 위상 변환기를 이용하여 도허티 증폭기의 전력 결합 특성을 개선하였다. 또한 구동단 첨두 증폭기 gate bais에 대한 포락선 추적 기술을 적용하여 효율을 개선하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.524-527
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• 1997

Conventional target tracking algorithms based on the linear estimation techniques perform quite efficiently when the target motion does not involve maneuvers. Target maneuvers involving short term accelerations, however, cause a bias in the measurement sequence. Accurate compensation for the bias requires processing more samples of which adds to the computational complexity. The primary motivation for employing a neural network for this task comes from the efficiency with which more features can be as inputs for bias compensation. A system architecture that efficiently integrates the fusion capabilities of a trained multilayer neural net with the tracking performance of a Kalman filter is described. The parallel processing capability of a properly trained neural network can permit fast processing of features to yield correct acceleration estimates and hence can take the burden off the primary Kalman filter which still provides the target position and velocity estimates.

• KIEAE Journal
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• 제14권2호
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• pp.21-28
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• 2014

This paper provides the up to date review of the shading effects on PV module performance and the associated detection algorithm related to the maximum power point tracking. It includes the brief explanations of the MMP variations due to the shading occurrence on the PV modules. Review of experimental and simulation studies highlighting the significant impacts of shading on PV efficiencies were presented. The literature indicates that even the partial shading of a single cell can greatly drop the entire module voltage and power efficiency. The MMP tracking approaches were also reviewed in this study. Both conventional and advanced soft computing methods such as ANN, FLC and EA were described for the proper tracking of MMP under shaded conditions. This paper would be the basic source and the comprehensive information associated with the shading effects and relevant MPP tracking technique.

• 전력전자학회논문지
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• 제8권3호
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• pp.260-265
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• 2003

태양의 고도와 방위각에 따라 태양광 발전 시스템의 에너지량이 차이가 많이 난다. 본 연구는 소규모 독립형 시스템인 가로등에 맞는 경제적인 추적장치 개발에 관한 것이다. 위치추적시스템은 프로그램을 사용한 방식으로서 시스템을 기존 유사 시스템에 비해 저가화를 실현하였다. 개발된 태양 위치 추적 시스템을 가로등에 적용하여 고정식과 추적식의 에너지량을 일정 기간 동안 실측 비교한 결과 평균 86%의 효율개선 효과를 보았다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.505-510
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• 2006

SVLBI (Space Very Long Baseline Interferometry) has some important potential applications in geodesy and geodynamics, for which one of the most difficult tasks is to precisely determine the orbit of SVLBI satellite. This paper studies several technologies which possibly will be able to determine the orbit of space VLBI satellite. And then, according to the sorts and characteristicsof satellite and the requirements for geodetic study and the geometry of GNSS (GPS, GALILEO) satellite to track the space VLBI satellite, the six Keplerian elements of SVLBI satellite (TEST-SVLBI) are determined. A program is designed to analyze the coverage area of the space of different heights by the stations of the network, with which the tracking network of TEST-SVLBI is designed. The efficiency of tracking TEST-SVLBI by the network is studied, and the results are presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.86-88
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• 2007

In solar power system, the height and azimuth of the sun are important parameters which control generated power magnitude. The tracking method that controls the daily generation magnitude according to latitude and longitude using the two axles is often used in the existing sunlight tracking system today. In this two-axle PV track control system, the self-load is concentrated on one FRAME. It is influenced of the regular load, snow load and the wind load, etc. It is difficult to set up the system in the conventional building. This research is a development about the small-scale economy track device of independent load-dispersing solar generation system. The position tracking algorithm is through the new coordinates transformation calculating the height and azimuth of the sun.