• Journal of Power Electronics
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• 제10권1호
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• pp.79-84
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• 2010

This paper presents a grid connected photo-voltaic system using a quasi-Z-source inverter (QZSI) for power stage reduction. The power stage can be reduced because of an additional shoot-through stage which is a characteristic of QZSI. Therefore, by utilizing a QZSI the system's efficiency can be increased. In this paper, for applying a QZSI to a PV system, control methods such as maximum power point tracking (MPPT), point of common coupling (PCC) current control and PWM are studied and verified through simulation and experiment. In order to explain the above controllers, the characteristics of a QZSI are first analyzed. Then the MPPT control technique with a modified P&O method, the PCC current control for the regulation of the dc-link capacitor voltage and the PWM methods for the proposed system are explained. The feasibility of the proposed algorithm is verified through simulation and experiment with a 3kW system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.446_447
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• 2009

This paper describes operational analysis results of the DC micro-grid using detailed model of distributed generation. Detailed model of wind power generation, photo-voltaic generation, fuel-cell generation was implemented with the user-defined model of PSCAD/EMTDC software that is coded with C-language. Various simulation results confirm that the DC micro-grid can operate without any problem in both the interconnected mode and the islanded mode. The operation analysis result confirms that the DC micro-grid make it feasible to provide power to the load stably.

• Journal of Advanced Marine Engineering and Technology
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• 제34권5호
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• pp.625-631
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• 2010

최근 몇 년간 에너지 위기에 대한 우려가 급격히 증가하고 있으며, 방대한 에너지소비에 따른 환경오염도 큰 문제로 대두되고 있다. 사회적으로 에너지 위기가 고조되고 있는 가운데 새로운 에너지나 신재생에너지에 대한 관심이 증가하고 있다. 본 연구는 이러한 문제를 해결하는 하나의 수단으로 태양에너지를 적극적으로 이용하기 위한 태양광발전시스템의 발전효율을 상승시키는 일환으로 대류열전달의 향상을 도모한 실험을 수행한 결과를 정리한 논문이다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.32-33
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• 2010

This paper describes a droop control method for the autonomous operation of DC distribution system using distributed generations and energy storage. The method suppress the circulating current, and each unit could be controlled autonomously without communication system. Detailed model of wind power generation, photo-voltaic generation, fuel-cell generation and battery was implemented with the user-defined model of PSCAD/EMTDC software that is coded with C-language. The simulation and experimental results confirms that the proposed DC distribution system make it feasible to provide power to the load stably and verify effectiveness of the proposed method.

• Advances in Energy Research
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• 제4권1호
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• pp.47-68
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• 2016

A well designed hybrid power system (HPS) can deliver electrical energy in a cost effective way. In this paper, model for HPS consisting of photo voltaic (PV) module and wind mill as renewable energy sources (RES) and solar lead acid battery as storage device connected to unidirectional grid is developed for peak demand reduction. Life time energy cost of the system is evaluated. One year hourly site condition and load pattern are taken into account for analysing the HPS. The optimal HPS is determined for least life time energy cost subject to the constraints like state of charge of the battery bank, dump load, renewable energy (RE) generation etc. Optimal solutions are also found out individually for PV module and wind mill. These three systems are compared to find out the most feasible combination. The results show that the HPS can deliver energy in an acceptable cost with reduced peak consumption from the grid. The proposed optimization algorithm is suitable for determining optimal HPS for desired location and load with least energy cost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.280-282
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• 2002

As EG(Embedded Generation : photo-voltaic, wind, combined heat and power, fuel cell, small hydro etc.) grows fast in adopting to peak load reducing at the middle or the end of distribution system, there much has been interested in interconnection of EG. This paper discusses the various issue of a embedded generator to power system and shows the simulation of its various situation that could happen (focusing on load-flow by EG) by using a commercial software CYME(PSAF) for load-flow. With a result of above simulation, this paper shows a way of possible solution briefly.

• 조명전기설비학회논문지
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• 제27권5호
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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.

• 한국전기전자재료학회논문지
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• 제28권11호
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• pp.743-747
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• 2015

In this paper, the power generation efficiency of the 4 [kW] fixed-concentrated type photovoltaic power generation system and that of the 4 [kW] single axis trace type photovoltaic power generation system were compared. For that purpose, the two types of photovoltaic power generation systems have been in operation for 1 year on an experimental basis. The amounts of power generated by the two types during the months of January through December and the characteristics of their operating times during the same period have been compared and analyzed. For the study, the type with higher efficiency was selected and the following conclusions have been reached. It was shown that the amount of power generated and the average operation times during the spring months of March through May are higher that those of the summer months of June through August when more sunlight is available. The reason for this phenomenon is thought to be that as the temperatures of the solar panel surface and the surrounding environment go up, the electric current decreases.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.518-522
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• 2001

In recent years, natural energy has attracted growing interest because of environmental concerns. Many studies have been focused on photovoltaic power generation systems because of the ease of use in urban areas. On the conventional system, many photovoltaic modules (PV modules) are connected in series in order to obtain the sufficient DC-bus voltage for generating AC output voltage at the inverter circuit. However, the total generation power on the PV modules sometimes decreases remarkably because of the shadows that partially cover the PV modules. In order to overcome this drawback, an AC module strategy is proposed. On this system, a small power DC-AC utility interactive inverter is mounted on each PV module individually and the inverter operates so as to generate the maximum power from the corresponding PV module. This paper presents a novel flyback-type utility interactive inverter circuit suitable for AC module systems. The feature of the proposed system are, (1) small in volume and light in weight, (2) stable AC current injection, (3) enabling a small DC capacitor. The effectiveness of the proposed system is clarified through the simulation and the experiments.

• 대한설비공학회지:설비저널
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• 제29권9호
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• pp.56-62
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• 2000

1997년 12월 일본 교토에서 개최된 COP3를 계기로 1999년 3월 에너지보존법이 대폭적으로 개정 및 강화되어졌다. 지구온난화의 주된 원인이 되는 이산화탄소는 에너지와 밀접한 관계를 가지고 있으므로, 에너지보존·자원보존의 추진은 지구온난화 대책의 추진과 동등한 의미를 가지고 있다고 하여도 과언이 아니다. 여기서는 건축설비계획의 관점에서 에너지보존법 개정의 요점과 그 대응책에 관해서 개요를 소개하였다.