• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.943-953
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• 2009

In this paper, we propose a radio sensor to measure the position of the sun for the solar tracker of a photovoltaic system. In order to satisfy the requirement for the measurement accuracy within ${\pm}5^{\circ}$, the sensor receiver with high gain, high sensitivity and wide bandwidth is designed and implemented. The receiver has the bandwidth of 104 MHz, the system gain of 69 dB and the sensitivity of 0.46 K at 5.1 GHz. The processes of design and implementation of the radio sensor receiver are described in this paper. The effectiveness of the proposed radio sensor in the measurement of the position of the sun is demonstrated experimentally under the condition of cloud cover. The results show the radio sensor can measure the position of the sun within the accuracy of ${\pm}4^{\circ}$ successfully.

• Journal of Energy Engineering
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• v.21 no.2
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• pp.124-132
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• 2012

This study presents the simulation results of Photopia when a lecture room with north-facing windows were illuminated by two different types of daylighting systems to improve the imbalance in its lighting conditions. Especially, the candela power distribution curves (CDCs) on a clear sunny day at the summer solstice, reaching $80^{\circ}$ in solar altitude, were analyzed with respect to the illuminance available at task areas (work planes). The difference between its illuminance on the north and south areas exceeded 1,000 lux without any daylighting system. This, however, decreased drastically with the application of a daylighting system. When a light tube system was introduced, it reduced from 906lx to 603lx and, even further to 308lx with the application of a dish concentrator system. Generally, the performance of a light tube system was greatly influenced by solar altitude while its effect on the dish concentrator system was rather negligible.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.4
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• pp.411-419
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• 2005

In this paper, a sliding mode observer for solar array current estimation in the photovoltaic power generation system is presented. The solar array current estimation Information is obtained from the sliding mode observer and fed into the maximum power point tracker to update the reference voltage. The parameter values such as inverter dc link capacitances cm be changed up to 50$\%$ from their nominal values and the linear observer can't estimate the correct state values under the parameter variations and noisy environments. The configuration of sliding mode observer is simple, but it shows the robust tracking performance against parameter variations and modeling uncertainties. In this paper, the method for constructing the sliding mode observer using equivalent control input is presented and the convergence of the proposed observer is verified by the Lyapunov method. The mathematical modeling and the experimental results verify the validity of the proposed method.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.39-40
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• 2005

Photovoltaic Power Generation system occupies an important position as an alternative energy source, converting directly sunlight into electricity,using a photovoltaic cell. The Purpose of this research is to present and confirm the effectiveness of concentration and tracking of sun in photovoltaic power generation. Comparative experiments were carried outwith two rating 75 watt solar modules in $25^{\circ}$ under condition of various times concentration, tracking and plain normal measuring generated voltages, currents and temperatures of back sheet of modules by internet monitoring system to find out which is best in economic sense. The experiments show that output power of concentration and tracking photovoltaic power generation is over 180% more then that of plain normal system.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.408-408
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• 2000

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 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 images.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.62-73
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• 2016

Daylighting systems offer substantial advantages over conventional ones in illuminating the building interior. Especially, considering that lighting accounts for about 28% of total energy consumption in buildings, the use of daylighting systems deem very important in lessening the dependency on artificial lighting. This work has carried out a survey and analysis to explore the characteristics and current status of various daylighting systems with solar tracking features recently introduced in Korea.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.395-396
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• 2010

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.321-323
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• 2006

The light gets darker from center to edge of the light source. Therefore, we can find the center of the sun using shading histogram. Moreover, we can track the exact position of the sun with the shading histogram. In this paper, we propose a new technique using image-processing of digital camera, in order to locate the position of the sun.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.561-563
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• 2006

This paper summarizes the results of these efforts by offering the PV generation system with solar tracking. The status of PV generation system with solar tracking components and interconnection and effects are semmarized. Hence this paper duscusses only points that might be useful for application.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.429-431
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• 1998

In this paper, the sun-seeker control system that is driven by DC motor is modeled on linear 2nd order time invariant system under some assumptions. For the analysis of output characteristics, theory is developed using digital control methods. Computer simulation and numerical analysis has been performed.