• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.31-41
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• 2014

This paper proposes the configuration of photovoltaic(PV) module considering the environment conditions of the PV system. The PV system is consisted of the series-parallel connection of the PV module. When shadows or changes of the radiation or an electrical characteristic in the solar cell are happened to PV system, the serious power loss will occur. If the PV module connected in series has the shadows, the output current is restricted to current of shaded PV module. Also if shadow is occurred to the parallel connection PV module, the output voltage is limited to voltage of shaded PV module. These problems are caused power loss. Therefore, this paper proposes the method that makes the output power of the PV module equalize by reconfiguration of PV module using the switching considering these environment conditions. A validity of the method proposed in this paper proves through comparing with performance of conventional PV module.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.461-466
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• 2007

There has been a great interest in printing technology as a low cost and mass production method for the application of printed electronics such as printed TFT, solar cell, RFID Tag, printed battery, and so on. In this study, apparatuses of gravure-offset printing are developed for fine line-width/gap printing and examining pattern distortion occurred in gravure-offset printing process. The fine line-width/gap pattern shows that it is possible to make around 20 micro-meter line-width/gap printing patterns. Pattern distortion is modeled, and the amount and shape of the distortion are calculated by using commercial FEM code. The roll-to-roll printing system under development consists of unwinder/rewinder, two printing units, one coating unit, drying units, guiding unit, vision system, and other auxiliary devices. For multi-layer printing, the system is designed to be capable of printing two different materials.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.143-148
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• 2018

In this paper, the optimal fuzzy logic controller(FLC) for a hybrid renewable energy system(HRES) is proposed. Generally, hybrid renewable energy systems can consist of wind power, solar power, fuel cells and storage devices. The proposed FLC can effectively control the entire HRES by determining the output power of the fuel cell or the absorption power of the electrolyzer. In general, fuzzy logic controllers can be optimized by classical optimization algorithms such as genetic algorithms(GA) or particle swarm optimization(PSO). However, these FLC have a disadvantage in that their performance varies greatly depending on the control parameters of the optimization algorithms. Therefore, we propose a method to optimize the fuzzy logic controller using the teaching-learning based optimization(TLBO) algorithm which does not have the control parameters of the algorithm. The TLBO algorithm is an optimization algorithm that mimics the knowledge transfer mechanism in a class. To verify the performance of the proposed algorithm, we modeled the hybrid system using Matlab Tool and compare and analyze the performance with other classical optimization algorithms. The simulation results show that the proposed method shows better performance than the other methods.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.606-613
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• 2010

This paper proposes a novel current-based maximum power point tracking (CMPPT) method for a single-phase photovoltaic power conditioning system (PV PCS) by using a modified incremental conductance method. The CMPPT method simplifies the entire control structure of the power conditioning system and uses an inherent current source characteristic of solar cell arrays. Therefore, it exhibits robust and fast response under a rapidly changing environmental condition. Digital phase locked loop technique using an all-pass filter is also introduced to detect the phase of grid voltage, as well as the peak voltage. Controllers of dc/dc boost converter, dc-link voltage, and dc/ac inverter are designed for coordinated operation. Furthermore, a current control using a pseudo synchronous d-q transformation is employed for grid current control with unity power factor. A 3 kW prototype PV PCS is built, and its experimental results are given to verify the effectiveness of the proposed control schemes.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.618-626
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• 2011

Solar cell is one of the most important new renewable energy for future energy generation. This paper presents a novel two stage DC/DC converter topology for PV PCSs. The proposed converter consists of an interleaved boost converter and a two-tank LLC resonant converter which is connected in parallel in primary and series in secondary. The main idea of this topology is that the system can achieve either unilateral or bilateral operations due to the input voltage level of the PV module, which leads to a better performance. The operating schemes on the proposed converter are analyzed and described. A 2.2kW prototype product is built, tested and verified.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.23-29
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• 2017

Solar and wind energy among the renewable energy produce irregular power because resource is difficult to control. When connected to grid have unstable. However, when the fuel cell system is connected to grid more stable because regular frequency and output power based on controllable hydrogen energy. To using fuel cell system in the household, it is important that the safety performance of power conditioning system(PCS) and it is important that evaluation method of electromagnetic compatibility(EMC). In this study, we consider that introduce power-frequency magnetic field immunity test before analyzed that compare with the EMC of the international standards and KGS AB 934 PC53. Also, we conduct that actual assessment and study on available the quantitative analysis as using complementary indicator.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.2
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• pp.311-324
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• 2015

This study presents computational analyses for low-drag aerodynamic design that are applied to modify a long-endurance UAV. EAV-2 is a test-bed for a hybrid electric power system (fuel cell and solar cell) that was developed by the Korean Aerospace Research Institute (KARI) for use in future long-endurance UAVs. The computational investigation focuses on designing a wing with a reduced drag since this is the main contributor of the aerodynamic drag. The airfoil and wing aspect ratio of the least drag are defined, the fuselage configuration is modified, and raked wingtips are implemented to further reduce the profile and induced drag of EAV-2. The results indicate that the total drag was reduced by 54% relative to EAV-1, which was a small-sized version that was previously developed. In addition, static stabilities can be achieved in the longitudinal and lateral-directional by this low-drag configuration. A long-endurance flight test of 22 hours proves that the low-drag design for EAV-2 is effective and that the average power consumption is lower than the objective cruise powerof 200 Watts.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.749-752
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• 2009

Anodized tubular titania ($TiO_2$) electrodes (ATTEs) are prepared and used as both the photoanode and the cathode substrate in a photoelectrochemical system designed to split water into hydrogen with the assistance of an enzyme and an external bias (solar cell). In particular, the ATTE used as the cathode substrate for the immobilization of the enzyme is prepared by two methods; adsorption and crosslinking. Results show that the optimized amount of enzyme is 10.98 units for the slurried enzyme, 3.66 units for the adsorbed one and 7.32 units for the crosslinked one, and the corresponding hydrogen evolution rates are 33.04, 148.58, and 234.88 umol/hr, respectively. The immobilized enzyme, specifically the chemically crosslinked one, seems to be much superior to the slurried enzyme, due to the enhanced charge-transfer process that is caused by the lower electrical resistance between the enzyme and the ATTE. This results in a greater number of accepted electrons and a larger amount of enzymes able to deal with the electrons.

• Economic and Environmental Geology
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• v.50 no.3
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• pp.251-256
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• 2017

This study presents measures to enhance the efficiency of Successive Alkalinity Producing Systems(SAPS), a natural biological purification method that prevents environmental pollution arising from the release of Acid Mine Drainage(AMD) from abandoned mines into rivers and groundwater. The treatment of AMD using SAPS is based on biological processing technology that mostly involves sulfate reducing bacteria(SRB). It has been proven effective in real-world applications, and has been employed in various projects on the purification of AMD. However, seasonal decrease in temperature leads to a deterioration in the efficiency of the process because sulfate-reducing activity is almost non-existent during cold winters and early spring even if SRB is able to survive. Against this backdrop, this study presents measures to enhance the activity of the SRB of the organic layer by integrating light emitting diode(LED)s in SAPS and to maintain the active temperature using LEDs in cold winters. Given that mine drainage facilities are located in areas where power cannot be easily supplied, solar cell modules are proposed as the main power source for LEDs. By conducting further research based on the present study, it will be possible to enhance the efficiency of AMD treatment under extreme cold weather using solar energy and LEDs, which will serve as an environmentally-friendly solution in line with the era of green growth.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.165-170
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• 2003

태양광발전은 수소에너지, 풍력발전 등과 더불어 화석에너지를 대신하여 전기생산을 할 수 있는 미래의 무공해 청정에너지 자원으로 주목받고 있다. 태양광 이용은 화석에너지에 비하여 경제성이 미흡하여 보급에 많은 애로가 있었으나 지속적인 연구개발로 인하여 경제성확보에 많은 성과가 있었고 또 환경오염에 대한 대체에너지 개발에 대한 사회전반에 걸친 폭 넓은 이해를 바탕으로 이용분야를 점차 확대하고 있다 우리나라의 태양광 이용은 낙도나 오지의 전원, 고속도로의 전광판 및 비상전화 전원, 산불방지 관측장치의 전원, 주거용 주택에서 전기기기 전원 등으로 이용되고 있다 반면 선진외국에서는 주로 대규모 발전용으로 연구 개발되고 있으며 국가적 차원에서 지속적인 투자가 이루어지고 있다. (중략)