• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.342-348
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• 2013

It proposes an efficient control algorithm to increase electric power transmission efficiency between photovoltaic power generating system and the grid. The main controller finds a maximum efficiency condition by considering the quantity of power generated from PV arrays, the number of inverters, and efficiency of PV inverter. According to the condition, a relay board arranges a point of contract of PV arrays. By the disposition of PV arrays, it assigns the optimized power on each PV inverter. Operational principle of the proposed maximum efficiency point tracking algorithm is given in detail. To verify the validity of the proposed approach, computer-aided simulation and experiment carried out.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.74-76
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• 2007

In this paper a maximum power point tracking(MPPT) techniques for power of PV(photovoltaic) systems are presented using boost converter for a connected single phase inverter. On the basic principle of power generation for the PV module, algorithms for maximum power point tracking are described by utilizing a boost converter to adjust the output voltage of the PV module. Based on output power of a boost converter, single phase inverter uses predicted current control to control four IGBT's switch in full bridge. Furthermore a low cost control system for solar energy conversion using the DSP is developed, based on boost converter to adjust the output voltage of the PV module. The effectiveness of the proposed inverter system is confirmed experimentally and by means of simulation. Finally, experimental results confirm the superior performance of the proposed method.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1256-1258
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• 2003

The solar cells should be operated at the maximum power point because its output characteristics are greatly fluctuate on the variations of insolation, temperature and loads. To obtain maximum power from solar cell, photovoltaic system cell power system usually requires maximum power point tracking controller. This paper propose Maximum power point tracking method using zero slope of differential value of maximum power. The power compare method traces to maximum power point rapidly but oscillate on the maximum power point largely, when quantity insolation variation is big. The power compare method is traces to maximum power point slowly but oscillate maximum point on the maximum power point smally, when quantity insolation variation is small. To solve two problem of the power compare method, designed zero slope of differential value of maximum power.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1761-1767
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• 2015

This paper deals with the solar tracking performance using a small heliostat, the light reduction rate of the sun light, and the performance of uniform irradiation of LED light for a plant factory. A high precision encoder is attached to the heliostat to improve tracking accuracy. As a result, our heliostat-based solar tracking systems track efficiently the movement of the sun light in experimental tests. The reduction rate of the sun light in the plant factory is then measured by using an illumination sensor. The average reduction rate is 4.29%, which represents lower light reduction rates. In uniform irradiation tests of LED light, sixteen points are measured, and overall deviations of irradiation were within eight percents.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.219-221
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• 2009

This paper analyzes efficiency of photovoltaic(PV) tracking system using solar location algorithm(SLA). Solar location tracking system is needed for efficiently and intensively using PV system independent of environmental condition. PV tracking system of program method is presented a high tracking accuracy without the wrong operating in rapidly changed insolation by the clouds and atmospheric condition. Therefore, this paper analyzes efficiency of PV system using SLA for more correct position tracking of solar. Also, controlled altitude angle and azimuth angle by applied algorithm is compared with data of korea astronomy observatory. And this paper analyzes the tracking error and proves the validity of applied algorithm.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.199-201
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• 2008

In this paper proposed the solar tracking system to use direct fuzzy control order to increase an output of the PV (Photovoltaic) array. The solar tracking system operated two DC motors driving by signal of photo sensor. The control of dual axes is not an easy task due to nonlinear dynamics and unavailability of the parameters. Recently, artificial intelligent control of the fuzzy control, neural-network and genetic algorithm etc. have been studied. The fuzzy control made a nonlinear dynamics to well perform and had a robust and highly efficient characteristic about a parameter variable as well as a nonlinear characteristic. Hence the fuzzy control was used to perform the tracking system after comparing with error values of setting-up, nonlinear altitude and azimuth. In this paper designed a DFC(Direct Fuzzy Control)controller for improving output of PV array and evaluated comparison with efficient of conventional PI controller. The data which were obtained by experiment were able to show a validity of the proposed controller.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1702-1704
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• 2005

In solar power system, the height and azimuth of the sun are important parameters which control generated power magnitude. The way that controls the daily generation magnitude according to latitude and longitude and uses two axles is often used in the existing sunlight racing system now. In this two-axle sunlight 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 building already built up. This research is a development about the small-scale economy track device of independent load-dispersing type solar generation system. The position track algorithm is through calculating the trail of height and azimuthal of the sun calculation to follow the sun.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.629-641
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• 2016

Understanding of how teachers change instruction can help predict what kind of educational materials is supportive or appropriate. On the basis of this idea, we explored elementary teachers' PCK progression on specific topics of astronomy: planet size and distance in solar system. To identify the development of PCK over time, we utilized learning progression (LP) as a conceptual framework. The progression of teacher PCK can also be illustrated as the hypothetical pathway from novice to expert like LP. Eight 5th grade elementary teachers participated in this study. We observed participating teachers' astronomy classes with the same topic. In order to document topic-specific PCK of participating teachers, we developed an analytic protocol consisting of four categories: knowledge of curriculum, knowledge of teaching strategies, knowledge of assessment, and astronomical thinking practice. In addition, we monitored the changes in the four participating teachers' PCK for two years in order to validate the evidences of the PCK progression. Participating teachers in this study took some intervention by attending a four-week pre-meeting with the researchers to profile an adaptive instruction. Through this research, we profiled four and five different levels of PCK progressions in three knowledge components (curriculum, teaching strategies, student assessment) and one astronomical thinking practice (systems thinking), respectively. Participating teachers demonstrated various levels and pathways in each component of PCK. This study released the empirical evidences in fostering instructional scaffolding, which is appropriate to the level of PCK of science teachers on specific topic.

• Cross-Cultural Studies
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• v.44
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• pp.239-281
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• 2016

This article explores the fate of futurism not only by tracing the entire process from the birth and decline of Russian futurism in the early 20th century and the so-called "Korean futurism" in the early 21st century, but also by delving into how their characteristics were shaped. In the first chapter, we investigate four groups of Russian futurism - Ego-Futurism, Cubo-Futurism, Tsentrifuga, and the Mezzanine of poetry, which were born in the age of utopianism before the Revolution. In the opera Victory Over the Sun, which was the culmination of the Zaum project of Cubo-futurists, we can find the initial shortcomings at the levels of language (Kruchenykh), music (Matyushin) and decoration and costume design (Malevich). In the second chapter, we examine chronologically how the term 'futurism' appeared in Korean literature history. In Korea, the term 'futurism' was born following the naming and classification of critic Kwon Heok-Woong, not by the voluntary manifestation of experimental poets such as Hwang Byong-Seung, thus this specific situation provoked stormy polemics between critics for futurism and critics against futurism in the Korean literary world. These polemics on futurist poetics have led to considerations of the relation of criticism to poetry.