• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.117-120
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• 2006

In this paper an integrated model of PV-AF (Photovoltaic-Active Filter) and PV-SPE(Photovoltaic Solid Polymer Electrolyte) system using PSCAD/EMTDC were explained in detaiil. The main concept of PV-AF system starts from the 'harmonics'. In order to deliver power to utility, PV system essentially needs a converter system. Here PV-AF system adds the function of active filter to the converter system installed in PV system, which was introduced already in several papers. PV-SPE system has been studied as a replacement of existing hydrogen production technology that emits large amount of carbon dioxide into atmosphere. Until now, these two systems, PV-AF and PV-SPE, have been considered separately However, in this paper, characteristics and advantages of combined system are discussed in detail.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.408-410
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• 2006

To chase maximum power point at every moment under a conventional MPPT control method, a voltage and current coming out from PV-cell are needed to be feedbacked. So, the structure of control circuit becomes so complex and the MPPT control is in risk of control failure. In the newly developed control method, the current flowing into SPE cell is the only one considerable factor. So, the structure of control circuit becomes simple and the manufacturing cost of the control device decreases. Especially, in case of a huge system of PV-SPE system, because the voltage coming out from PV-cell is not needed to be feed backed, this system can be operated much more safely. In this paper, the PV-SPE system was actually manufactured based on the simulation model of PSCAD/EMTDC program and the results tested were shown. Authors are sure that it is the most useful method to maximize power from PV to SPE with only a feedback of SPE input current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1064_1065
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• 2009

PV (Photovoltaic) power generation system has been widely studied as a clean and renewable power source. Tracking the MPP (maximum power point) of a PV array is usually an essential part of a PV system. This paper describes POS (Photovoltaic Output Sensorless) MPPT method and optimization technique of its operational characteristics for grid-connected PV generation system. A DC-DC converter has been used to step-up the PV voltage and DC-AC converter has been used for connecting the system to the grid. Optimization technique has been implemented to optimize the current and voltage controller gain parameters and duty ratio increment of DC-DC converter. Simulation results reveal that the proposed control has better response.

• 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.

• 한국태양에너지학회 논문집
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• 제36권5호
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• pp.1-8
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• 2016

In this paper, we evaluated the effect of a silica-based Anti-Reflection(AR) coating for PV modules. The coating technique can be easily applied to large-scale PV modules at room temperature with improvements of the optical properties that is qualified by the optical transmission measurements on the coated cover glass of the modules. The power improvement of the large-scale PV modules shows the increasing about 2.4% at standard condition of the coating technique on average. To improve the AR coating effect of the PV modules, we have characterized the individual PV modules by the measurements of DC power output, modified performance ratio(PRm) and the regression. The results show that the significant improvements of the AR coating effect are 6.4%, 5.5% and 4.5% of increasing of the performances by using the measurements of DC power output, modified performance ratio(PRm) and the regression, respectively.

• KIEAE Journal
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• 제11권6호
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• pp.133-138
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• 2011

This paper presents energy self-sufficiency simulated in municipal wastewater treatment plants (WWTPs) by adopting solar energy production systems that were simulated by varying azimuth and super-hydrophilic coating on the surface of photovoltaic (PV). Relative to the national average energy consumption in WWTPs, the employment of 100 kW PV system was simulated to achieve 2.75% of energy self-sufficiency. The simulated results suggested that the installation of PVs toward South or Southwest would produce the highest energy self-sufficiency in WWTPs. When super-hydrophilic coating was employed in the conventional PV, 5% of additional solar energy production was achievable as compared to uncoated conventional PV. When 100 kW of PV system was installed in a future test-bed site, Kihyeung Respia WWTP located in Yongin, South Korea, the energy self-sufficiency by solar power was simulated to be 1.77%. The simulated solar power production by azimuth and super-hydrophilic coating will be useful reference for practitioners in designing the solar PV systems in the WWTPs.

• 한국태양에너지학회 논문집
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• 제27권2호
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• pp.37-44
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• 2007

As photovoltaic(PV) power generation system becomes more common, it will be necessary to investigate islanding detection method for PV systems. Islanding of PV systems can cause a variety of problems and must be prevented. However, if the real and reactive power of the load and PV system are closely matched, islanding detection by Passive methods becomes difficult. Also, most active methods lose effectiveness when there are several PV systems feeding the same island. The active frequency drift positive feedback method(AFDPF) enables islanding detection by forcing the frequency of the voltage in the island to drift up or down. In this paper the research for the minimum value of chopping fraction gain applied digital phase-locked-loop (DPLL) to AFDPF considering output power quality and islanding prevention performance are performed by simulation and experiment according to IEEE Std 929-2000 islanding test.

• Journal of Power Electronics
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• 제15권1호
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• pp.256-267
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• 2015

Grid-connected transformerless photovoltaic (PV) inverters (TPVIs) are increasingly dominating the market due to their higher efficiency, lower cost, lighter weight, and reduced size when compared to their transformer based counterparts. However, due to the lack of galvanic isolation in the low voltage grid interconnections of these inverters, the PV systems become vulnerable to leakage currents flowing through the grounded star point of the distribution transformer, the earth, and the distributed parasitic capacitance of the PV modules. These leakage currents are prohibitive, since they constitute an issue for safety, reliability, protection coordination, electromagnetic compatibility, and module lifetime. This paper investigates a wide range of multi-kW range power rating TPVI topologies and classifies them in terms of their leakage current attributes. This systematic classification places most topologies under a small number of classes with basic leakage current attributes. Thus, understanding and evaluating these topologies becomes an easy task. In addition, based on these observations, new topologies with reduced leakage current characteristics are proposed in this paper. Furthermore, the important efficiency and cost determining characteristics of converters are studied to allow design engineers to include cost and efficiency as deciding factors in selecting a converter topology for PV applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.216-217
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• 2007

In this study, we analyzed the electrical loss characteristics between ribbon and output terminal of constituent material according to electrical resistance during interconnection process of PV module. From this result, the electrical output power reduction rate caused by interaction between ribbon and cell's interconnection was 2.88%. There was 1W electrical output power reduction through the 16 solar cells. So it is expected that the wider size of PV module gives the higher loss in electricity production. Also, the average output power of PV module passed lamination process was increased by 0.081W per one solar cell and the increase rate was 3.7%.PV module's electrical loss before and after lamination process according to constituent material's terminal was 0.49W and 0.50W, respectively.

• 전력전자학회논문지
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• 제19권1호
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• pp.31-40
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• 2014

This paper describes an optimal configuration for multi-central inverters in a medium-voltage (MV) grid, which is suitable for large-scale photovoltaic (PV) power plants. We theoretically analyze a proposed common-mode equivalent model for problems associated with multi-central transformerless-type three-phase full bridge(3-FB) PV inverters employing two-winding MV transformers. We propose a synchronized PWM control strategy to effectively reduce the common-mode voltages that may simultaneously occur. In addition, we propose that the existing 3-FB topology may also have the configuration of a multi-central inverter with a two-winding MV transformer by making a simple circuit modification. Simulation and experimental results of three 350kW PV inverters in a multi-central configuration verify the effectiveness of the proposed synchronization control strategy. The modified transformerless-type 3-FB topology for a multi-central PV inverter configuration is verified using an experimental prototype of a 100kW PV inverter.