• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1721-1726
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• 2011

Recently, interest in renewable energy is increased due to exhaustion of fossil fuel and environmental pollution all over the world, therefore the solar power generation using solar energy is many researched. The solar power generation is required solar tracking control and high concentration solar thermal collector because generation performance is depended on concentrator efficiency. This paper proposes high efficiency solar power generation with two-axis tracking control using dish-type solar thermal collector that has excellent thermal collector performance and tracking algorithm that can be accurately tracked solar position. This paper proves validity through analysis with accuracy of tracking algorithm and generating efficiency.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.4
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• pp.388-396
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• 2011

Sun tracking system is the most important subsystem in parabolic dish type solar thermal power plant, since it determines the amount of thermal energy to be collected, thus affects the efficiency of solar thermal power plant most significantly. Various types of sun tracking systems are currently used. Among them, use of photo sensors to located the sun(which is called sensor type) and use of astronomical algorithm to compute the sun position(which is called program type) are two of the mostly used methods. Recently some uses CCD sensor, like CCD camera, which is called image processing type sun tracking system. This work is concerned with the analysis of sun tracking performance of various types of sun tracking systems currently used in the parabolic dish type solar thermal power plant. We first developed a sun tracking error measurement system. Then, we evaluate the performance of five different types of sun tracking systems, sensor type, program type, hybrid type(use of sensor and computed sun position simultaneously), tracking error compensated program type and image processing type. Experimentally obtained data shows that the tracking error compensated program type sun tracking system is very effective and could provide a good sun tracking performance. Also the data obtained shows that the performance of sensor type sun tracking system is being affected by the cloud significantly, while the performance of a program type sun tracking system is being affected by the sun tracking system's mechanical and installation errors very much. Finally image processing type sun tracking system can provide accurate sun tracking performance, but costs more and requires more computational time.

• Journal of the Korean Solar Energy Society
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• v.29 no.1
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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.

• Journal of the Korean Solar Energy Society
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• v.29 no.2
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• pp.39-46
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• 2009

Heliostat, as a mirror system tracking the sun's movement, is the most important subsystem determining the efficiency of solar thermal power plant. Thus the accurate sun tracking performance under the various hazardous operating condition, is required. This study presents a methodology of development of the solar ray tracing technique and the application of it in the analysis of sun tracking error due to the heliostat geometrical errors. The geometrical errors considered here are the azimuth axis tilting error and the elevation axis tilting error. We first analyze the geometry of solar ray reflected from the heliostat. Then the point on the receiver, where the solar ray reflected from the heliostat is landed, is computed and compared with the original intended point, which represents the sun tracking error. The result obtained shows that the effect of geometrical error on the sun tracking performance is varying with time(season) and the heliostat location. It also shows that the heliostat located near the solar tower has larger sun tracking error than that of the heliostat located farther.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.67-73
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• 2013

The conversion of solar radiation into electrical energy by Photo-Voltaic (PV) effect is a very promising technology, being clean, silent and reliable, with very small maintenance costs and small ecological impact. The output power produced by the PV panels depends strongly on the incident light radiation. The continuous modification of the sun-earth relative position determines a continuously changing of incident radiation on a fixed PV panel. The point of maximum received energy is reached when the direction of solar radiation is perpendicular on the panel surface. Thus an increase of the output energy of a given PV panel can be obtained by mounting the panel on a solar tracking device that follows the sun trajectory. Tracking systems that have two axes and follow the sun closely at all times during the day are currently the most popular. This paper presents research conducted into the performance of Solar tracking system with photosensors. The results show that an optimized dual-axis tracking system with photosensor performance and analysis. From the obtained results, it is seen that the sun tracking system improves the energy and energy efficiency of the PV panel.ti-junction CPV module promises to accelerate growth in photovoltaic power generation.

• Journal of the Korean Solar Energy Society
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• v.21 no.4
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• pp.55-62
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• 2001

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using a computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the captured images.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.557-562
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• 2014

It is well known that solar tracking systems can increase the efficiency of exiting solar panels significantly. In this paper, a hybrid solar tracking system has been developed by using both astronomical estimates from a GPS and the image processing results of a camera vision system. A decision making process is also proposed to distinguish current weather conditions using camera images. Based on the decision making results, the proposed hybrid tracking system switches two tracking control methods. The one control method is based on astronomical estimates of the current solar position. And the other control method is based on the solar image processing result. The developed hybrid solar tracking system is implemented on an experimental platform and the performance of the developed control methods are verified.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.22-31
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• 2009

Canting is the optical alignment of mirror facets of heliostat such that the heliostat could focus the energy as a unit concentrator. Canting could improve the optical performance of heliostat and thus improves the efficiency of heliostat and ultimately improves the efficiency of the solar thermal power plant. This study discusses the effect of mirror canting, especially off-axis canting, used to compensate the sun tracking error caused by the heliostat geometrical errors. We first show that the canting could compensate the sun tracking error caused by the heliostat geometrical errors. Then we show that the proper canting time could exist, depending on the heliostat location. Finally we show how much the sun tracking performance could be improved by canting, by providing RMS sun tracking error. The limitation and caution of using canting to improve the sun tracking performance are also discussed.

• Journal of Engineering Education Research
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• v.17 no.1
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• pp.3-11
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• 2014

The purpose of this study was to verity the effect of project method on the task performance ability in development of a solar-tracking-control-system of specialized high school. In order to carry out this study, 2 classes of technical high school in Jeonbuk are chosen as experimental and control groups. The experimental group was taught by project method and the control group was taught by traditional instruction. Project method was designed by 4 stages-selection of goal, planning, implementation and evaluation. According to these stages, experimental group's students carried out the project that developing solar tracking control system in solar generation. The results of this study are as follows; the project method was more effective than the traditional instruction in planning ability for task performance and implementation ability, subordinates of task performance ability. However, information gathering ability and evaluation ability on task performance, others in subordinates, it is not clear that the project method is more effective.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.121-125
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• 2009

There have been many developed systems for harnessing the solar energy such as solar water heaters, solar thermal power systems, PV systems, daylighting and solar hydrogen systems. all of them are capable of reducing $CO_2$ emission. However, the efficiency of those systems which work without a solar tracker is lower. This paper is a step by step procedure for fabrication and a performance test of a solar tracking system. The system developed in this study consists of motion controllers, motor drives, step-motors, feedback devices and application. CdS sensors are introduced into the solar tracking system for playing a primary role in poor conditions for tracking due to a gear backlash and a strong wind. Mini-dish was used as a concentrator for collecting sun light. The solar position data, in terms of azimuth and elevation, sunrise and sunset times was compared with those of KASI(Korea Astronomy & Space Science Institute). The results presented in this article provide the high accuracy of the present system in solar tracking and indicate a potential for energy savings.