• Journal of Power Electronics
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• v.8 no.4
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• pp.371-380
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• 2008

This paper describes the Utility Interactive PV (UIPV) system which can improve the peak-cut effect by adding an energy storage device of batteries to the power converter. The proposed system has three possible operation modes depending on relative condition of PV output, which can have the power shaping function covering the peak power for 3 hours. A new power circuit and an application algorithm have been applied to the UIPV system which is based on working PV system during a 3-hour peak time. The energy relationship by the proposed system is analyzed theoretically and experimentally. The proposed system is evaluated at the viewpoint of cost and total spacing, which enables the proposed UIPV system to have the reduction of the peak power demand and hence to improve the power capacity of peak cut.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.271-273
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• 2005

Islanding of PV systems occurs when the utility grid is removed but local sources continue to operate and provide power to local loads. Islanding is one of the serious problems in an electric power system connected with dispersed power sources. Also, this can present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding phenomena. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new anti-islanding algorithm is proposed and its validity is verified through simulation and experimental results for utility interconnection of PV system.

• Journal of the Korean Solar Energy Society
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• v.25 no.1
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• pp.27-34
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• 2005

This study aims to evaluate application of a heat recovery ventilator(HRV) using photovoltaic(PV) system. To this end, we analyzed performance of a PV system, which it was evaluated by monthly power wattage and conversion efficiency according to design capacity of a HRV. The results of this study can be summarized as follows. (1) A conversion efficiency of the PCS was evaluated about 86% in rated power. (2) A maximum, minimum and average output power were respectively analyzed 49.2W, 47.3W, and 48.8W. (3) Total power wattage of 200W PV system was 211kW and it was 316kW in case of 300W PV system. (4) Insufficient electrical power of a duct and window type ventilation system was respectively calculated 133.5kW and 147.7kW.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.516-519
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• 2003

3kW photovoltaic (PV) systems and data acquisition system are constructed for performance analysis of PV system at field demonstration test center (FDTC) of Korea. As climatic and irradiation conditions are varied, the performance characteristics of PV system are collected and analyzed in data acquisition system. From these results, the performances of gird-connected power conditioning system (PCS) fur PV system have been evaluated and analyzed. Furthermore, performance indices of grid-connected PCS e.g. output power, efficiency, loss factor, and the other index at the site are reviewed.

• Journal of the Korean Solar Energy Society
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• v.39 no.2
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• pp.1-9
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• 2019

In order to increase the power generation efficiency of the photovoltaic system, a new algorithm that can follow the maximum power point of the photovoltaic power generation system having nonlinear output characteristics is proposed. Conventional maximum power point tracking (MPPT) algorithms such as Perturbation and Observation (P&O) and InCond (Increment and Conductance) schemes can not find the global maximum power point at a plurality of pole points in the unmatched state of unbalanced PV modules. However, even if the global maximum power point is found at a plurality of pole points, the global maximum power that can not be the real maximum power by the photovoltaic generation system. In order to solve this problem, a few PV companies propose installing several small PV inverters instead of if big one. However, since this will require additional costs, we herein propose a Multi-MPPT system using individual 3-point MPPT to track true MPPT at a plurality of pole points in the unmatched state of unbalanced PV modules.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.3-4
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• 2012

PV 시뮬레이터는 제한된 공간에서 PCS(Power Conditioning System)의 성능을 평가하거나, 고장유무를 검사하는데 필수적인 장비이다. PV 시뮬레이터가 PV 어레이와 동일한 동작을 하기 위해서는 다양한 재질의 PV cell에 대하여 모델링이 가능해야한다. 본 논문은 EN50530에 규정되어 있는 최대전력운 전범위인 $V_{MPP}{\pm}10%$ 구간에서 발생하는 오차를 다른 PV cell 모델링 알고리즘과 비교하고 제안한 알고리즘의 우수함을 증명하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.212-213
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• 2007

Grid-connected PV(Photovoltaic) power generation system has experienced increasing attention in recent years. But the growing number of non-linear equipments, such as, inverters, has been demanding the compensation for the disturbances caused by them. These non-linear loads may cause poor power factor and high degree of harmonics. Installation of an AF(active filter) can be one of the solutions to mitigate the line distortion, but it requires additional costs. On the other hand, many PV systems have been interconnected to the distribution system. So, the PV system combined with the function of the active filter system can be useful for the application in the power distribution system. In this paper, PV-AF system using DSP (Digital Signal Processing) controller confirmed that it is possible to combine the AF theory to the three phase PV system connected to the utility under various irradiation conditions.

• Current Photovoltaic Research
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• v.4 no.4
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• pp.159-163
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• 2016

Piled snow upon PV module interferes with Photoelectric Effect process through photovoltaic directly. As a result of this phenomenon, its generation efficiencies keep decreasing or are stuck at zero power generating status. In addition, PV facilities have been installed on those places such as water surface, roof-top, and other isolated places, dealing with conditions of "Securing high REC weighted value", "Difficulty of securing land" and so forth. Through this study, we are able to actualize the function of heating over PV modules when it snows. We adopted laminating method through heating film and modules, guaranteeing warranty more than for 25 years. Also we are trying remote control systemically, not by hardware control, to run parallel with automatic driving and monitoring system which enable to control operation time, insolation, amount of snowfall automatically. We applied analysis of actual proof to both snow removal PV system and general PV power system, and these led to bear power consumption analysis while snow-removing, and its comparison after finishing the task as "One stone, two birds." In the long run, we could carry out economic analysis against snow removal system, and this helps to verify the most maximized control method for snow removal conditons on a basis of weather information. this study shall let prevent people from negligent accidents, and improve power generation problems as mentioned from the top. Ultimately, we expect to apply this system to heavy snowfall regions in winter season in spite of its limited system installaion in Korean territory, initially.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.8
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• pp.177-184
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• 2019

Recently, electric power usages and peak loads from buildings are increasing due to higher outdoor air temperatures and/or abnormal climate during the summer period. As one of the eco-friendly measures, a renewable energy system has been received much attention. Particularly, interest on a photovoltaic (PV) system using solar energy has been rapidly increasing in a building sector due to its broad applicability. In using the PV system, one of important factors is the PV efficiency. The normal PV efficiency is determined based on the STC(Standard Test Condition) and the NOCT(Nominal Operating Cell Temperature) performance test. However, the actual PV efficiency is affected by the temperature change at the module surface. Especially, higher module temperatures generally reduce the PV efficiency, and it leads to less power generation from the PV system. Therefore, the analysis of the relation between the module temperature and PV efficiency is required to evaluate the PV performance during the summer period. This study investigates existing algorithms for calculating module surface temperatures and analyzes resultant errors with the algorithms by comparing the measured module temperatures.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.14-21
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• 2013

Today, energy problem has become an important issue, and a development of renewable energy is urgent. In architectural fields, a research of the energy efficient lighting system using renewable energy is in progress. The energy efficient lighting system could be realized by integrating a daylight responsive LED lighting control system and a blind PV system. This system is able to save and generate electric energy. Efficiency of this system depends on control methods of blind PV. As a preliminary research, this research analyzed power generation and inflow of available daylight according to control method of blind PV.