• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.171-174
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• 2008

In this paper, interactive inverter in series 2 module inverters is proposed. One of two inverters makes equivalent voltage. Another removes harmonics, contained in source voltage, through control inductor current. As a result, it remains only basic frequency voltage to produce the purely sinusoidal current wave. Using 2 module inverters is verified with simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.149-155
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• 2023

Photovoltaic power generation is the most familiar power generation facility among new and renewable energies, and its supply began to expand about 10 years ago, and at this point, interest in solutions and technologies for system maintenance management is increasing. In particular, it is necessary to take measures to maximize the overall efficiency of the solar power generation system, whether or not there is an abnormality in the solar power generation system, and when to replace parts. The PV inverter, one element of the photovoltaic power generation system, is a power conversion system that relies on power switching devices, and DC-Link capacitors are used according to the configuration of DC/DC converters and DC-AC inverters. These DC capacitors also affect system safety (Safety) through renewable energy facilities due to the decrease in power generation of PV inverters, power loss, and increase in harmonics (THD, total distortion of AC output current) due to aging and deterioration due to long-term use. factors can be analyzed. Therefore, in this paper, the PV inverter operating characteristics according to the DC capacitor capacity state currently operating in the photovoltaic power generation system were considered, and research contents were proposed to secure the safety and reliability of renewable energy facilities.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1037-1047
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• 2017

The Differential Power Processing (DPP) converter is a promising multi-module photovoltaic inverter architecture recently proposed for photovoltaic systems. In this paper, a DPP converter architecture, in which each PV-panel has its own DPP converter in shunt, performs distributed maximum power point tracking (DMPPT) control. It maintains a high energy conversion efficiency, even under partial shading conditions. The system architecture only deals with the power differences among the PV panels, which reduces the power capacity of the converters. Therefore, the DPP systems can easily overcome the conventional disadvantages of PCS such as centralized, string, and module integrated converter (MIC) topologies. Among the various types of the DPP systems, the feed-forward method has been selected for both its voltage balancing and power transfer to a modified H-bridge inverter that needs charge balancing of the input capacitors. The modified H-bridge multi-level inverter had some advantages such as a low part count and cost competitiveness when compared to conventional multi-level inverters. Therefore, it is frequently used in photovoltaic (PV) power conditioning system (PCS). However, its simplified switching network draws input current asymmetrically. Therefore, input capacitors in series suffer from a problem due to a charge imbalance. This paper validates the operating principle and feasibility of the proposed topology through the simulation and experimental results. They show that the input-capacitor voltages maintain the voltage balance with the PV MPPT control operating with a 140-W hardware prototype.

• Journal of Power Electronics
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• v.13 no.2
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• pp.296-303
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• 2013

This paper proposes a high efficiency three-phase cascaded phase shifted H-bridge multi-level inverter without DC/DC converters for grid-tied multi string photovoltaic (PV) applications. The cascaded H-bridge topology is suitable for PV applications since each PV module can act as a separate DC source for each cascaded H-bridge module. The proposed phase shifted H-bridge multi-level topology offers advantages such as operation at a lower switching frequency and a lower current ripple when compared to conventional two level topologies. It is also shown that low ripple sinusoidal current waveforms are generated with a unity power factor. The control algorithm permits the independent control of each DC link voltage with a maximum power point for each string of PV modules. The use of the controller area network (CAN) communication protocol for H-bridge multi-level inverters, along with localized PWM generation and PV voltage regulation are implemented. It is also shown that the expansion and modularization capabilities of the H-bridge modules are improved since the individual inverter modules operate more independently. The proposed topology is implemented for a three phase 240kW multi-level PV power conditioning system (PCS) which has 40kW H-bridge modules. The experimental results show that the proposed topology has good performance.

• 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.

• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.190-194
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• 2017

Present-day solar panels incorporate inverters as their core components. Switching devices driven by specialized power controllers are operated in a transformerless inverter topology. However, some challenges associated with this configuration include the absence of isolation, causing leakage currents to flow through various components toward ground. This inevitably causes power losses, often being also the primary reason for the power inverters' analog equipment failure. In this paper, various aspects of the leakage currents are studied using different circuit analysis methods. The primary objective is to convert the leakage current energy into a usable DC voltage source. The research is focused on harvesting the leakage currents for producing circa 1.1 V, derived from recently developed rectifier circuits, and driving a $200{\Omega}$ load with a power in the milliwatt range. Even though the output voltage level is low, the harvested power could be used for charging small batteries or capacitors, even driving light loads.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.43-48
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• 2010

The performance of photovoltaic systems could be affected by various factors including installing conditions of modules, and their own efficiencies of solar cells and inverters. The installing conditions of a photovoltaic system including array types, tilting angles, azimuth, locations, quantities of sunshine, optimum angles of inclination and separated distance are analyzed using the SolarPro & Minitep SW simulation program, inorder to set up the installing conditions for improving system performance. The result from the simulation of the 500kWp PV system of Kochang with optimal installing conditions compared with normal conditions shows that the capacity factor has been increased from 11.02% to 12.06%.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1362-1364
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• 2003

Most of PV(Photovoltaic) inverters are utilizing voltage source type. Normally in this type, an input capacitor is connected at the input of a inverter to keep dc voltage constant. However, it does not seem to be well known how to determine the appropriate value of the capacitor. By developing non-linear transient analysis, the author suggest an approach to give a guideline. An Implicit trapezoidal formula was used to do this calculation.

• Journal of Korea Multimedia Society
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• v.23 no.10
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• pp.1307-1317
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• 2020

In recent years, the PV plant is gradually increasing in korea and has begun to focus on PV system O&M(Operation and Management). The legacy PV system can hardly be gathering realtime information. That is why it is difficult for the facility to respond immediately to situations in which problems arise. This leads to economic losses due to reduced power generation. In this study, we implemented an RMC(Remote Maintenance Control) gateway that supports multi-area equipment(inverters, junction boxes, switchboards, environmental sensors) that are not limited to specific manufacturers. It provides a function to visualize the collected data. Users can easily check the power generation and operation status of PV system equipment. In the future, we will develop an algorithm capable of analyzing beta factors that cause equipment performance degradation, parts aging, and deterioration using data collected from facilities. We intend to use this algorithm as a fundamental technology for O&M by transplanting it to the RMC gateway.