• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.1
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• pp.22-28
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• 2006

Establishment of practicalization technologies is becoming more important as dissemination of domestic PV system has been increased. To improve performance through PV system optimization, this paper presents loss factors analysis of PV system based on results of field operational test. Also, as simulation results are compared with actual operational ones, the main loss factors of PV system due to performance degradation are reviewed.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.202-205
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• 2006

In the PV power system, output of the PV array must contain inherent ripples due to the single-phase inverter. So the function of maximum power point tracking to increase the output efficiency of PV system is degraded. Therefore, to overcome this problem, this paper presents a control strategy for the reducing ripples of the PV array output in grid-connected photovoltaic power system. The proposed control system consists of two loops the maximum power point tracking loop using the perturbation and observation method is used to calculate the reference solar array terminal voltage(Vref) for reducing ripples of the PV array output and the PI control loop is used to regulate the solar array output voltage according to the Vref. The performance of proposing control strategy is analyzed by means of the PSCAD/EMTDC simulation. As a result, we may obtain the high performance of the proposed control strategy.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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• pp.77-85
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• 2018

Renewable energy has been increasingly used and widely acclaimed as one of the solutions to rampant environmental problems. Among numerous kinds of renewable sources, the penetration rate of the PV system is relatively higher than that of others due to ease of installation. However, one disadvantage of the PV system is its dependence on weather condition. The PV system is especially critical when it is used for standalone systems because it cannot operate when the power generated from a PV module is not enough. Therefore, PV systems are often used with an energy storage system, such as batteries, to store backup energy when the weather condition is insufficient to supply power to the system. Blackout time can be reduced by increasing the size of the energy storage system, but it is a trade-off with system cost. In this work, optimal sizing of a standalone PV system is proposed to supply power to the system without blackout. The sizing of PV modules and batteries is performed by a simulation based on actual irradiation data collected during the past five years. The Life cycle costing of each system is evaluated to determine an optimal set of PV modules and batteries among several different combinations. The standalone PV system designed by the proposed method can supply power to the system with no interruption as long as the weather condition is similar to those of the past five years.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1364-1366
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• 2002

The Photovoltaic(PV) generation system is a promising source of energy for the future. Since the need for renewable energy has been increased, the research of PV generation system has also been progressed. Recently, cost down of PV generation system has been accomplished and practical technologies of the solar energy developed, Moreover, grid connected PV generation system are becoming actual and general. Operational technology of the grid connected PV generation system is being a hot issue. Power output of PV system is directly affected by wether conditions. When AC power supply is needed, power conversion by an inverter and a MPPT control are necessary. In this paper, for stability improvement of PV generation system. Active filter(AF) function is added to PV generation system, and simulations of PV-AF system under various weather conditions are performed.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.225-227
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• 2002

In this paper, novel concept of a photovoltaic(PV) power generation system adding the function of active filter(AF) is proposed. Even PV power generation system can be treated to a harmonics source for the power distribution system, it is necessary that the function of AF system in grid connected PV power generation system. Active Filters intended for harmonic solutions are expending their functions from harmonic compensation of nonlinear loads into harmonic isolation between utilities and consumer, and harmonic damping throughout power distribution system. So, the PV system combined the function of AF system can be usefully applied in power distribution system. Here, the control strategy of PV-AF system is introduced.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.480-485
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• 2012

Use of photovoltaic (PV) power generation system will become more widespread in the future due to anticipated cost reduction in PV technology. As the capacity of PV systems increases, a variation of power system frequency may prevent the stable output of PV system. However, the standard for the frequency protection of distributed generation in Korea Electric Power Corporation (KEPCO)'s rule does not include the setting of frequency protection. Therefore, this paper analyzes the correlation between the frequency protection requirements and the stability of grid-connected PV system for the adjustable operating setting of frequency protection. The distribution system interconnected with 3 MW PV system is modeled by Matlab/Simulink. The various values of frequency are simulated. For studied cases, the stability of PV system is analyzed. It is concluded that the setting of frequency protection is necessary to consider the stability of PV system.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.57-62
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• 2005

Grid-connected photovoltaic (PV) systems were installed and monitored at the field demonstration test center (FDTC) in Korea in October 2002. Before long-term field testing of installed PV systems, the performances of PV components were evaluated and compared through short-term performance tests of each of the PV system components such as power conditioning system and PV module under standard test conditions. A data acquisition system has been constructed for measuring and analyzing the performance of PV systems to observe the overall effect of environmental conditions on their operation characteristics. Performances of PV systems have been evaluated and analyzed not only for component perspective (PV array, power conditioning unit) but also for global perspective (system efficiency, capacity factor, electrical power energy) by review of the field test and loss factors of the systems. These results indicate that it is highly imperative to develop an optimum design technology of grid connected PV systems. The objective of this paper is not only to evaluate and analyze the performance of domestic PV systems application through long-term field testing at FDTC but also to develop evaluation, analysis and optimum technology for long-term stability and reliability of grid-connected PV systems in Korea.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.291-295
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• 2009

Economic and environmental concerns over fossil fuels encourage the development of photovoltaic(PV) energy systems. Due to the intermittent nature of solar energy. energy storage is needed in a stand-alone PV system for the purpose of ensuring continuous power flow. Grid-connected PV system that supply power in a critical load demand require to curb power fluctuation. In this case. SCB is a effectiveness in controlling power variation due to intrinsic PV system. We propose the Matlab/Simulink dynamic model and power flow characteristics of a hybrid energy system with PV and SCB.

• Transactions on Electrical and Electronic Materials
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• v.17 no.6
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• pp.359-362
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• 2016

In the PV (Photovoltaic) power system, a junction box collects the DC voltage generated from the PV module and transfers it to the PCS (power conditioning system). The junction box prevents damage caused by the voltage difference between the serially connected PV modules and provides convenience while repairing or inspecting the PV array. In addition, the junction box uses the diode to protect modules from the inverse current when the PV power system and electric power system are connected for use. However, by using the reverse blocking diode, heat is generated within the junction box while generating electric power, which decreases the generating efficiency, and causes short circuit and electric leakage. In this research, based on the purpose of improving the performance of the PV module by decreasing the heat generation within the junction box, a junction box with a built-in bypass circuit was designed/manufactured so that a certain capacity of current generated from the PV module does not run through the reverse blocking diode. The manufactured junction box was used to compare the electric power and heating power generated when the circuit was in the bypass/non-bypass modes. It was confirmed that the electric power loss and heat generation indicated a decrease when the circuit was in the bypass mode.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.334-341
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• 2021

Operation modes and control strategies for single-phase mobility charging station utilizing photovoltaic (PV) generation and energy storage systems (ESS) are proposed. This approach generates electric power from PV to transmit the mobility, ESS, and then transfer it to the grid when surplus electric power is generated during daytime. However, the PV power cannot be generated during night-time, and ESS and the mobility system can be charged using grid power. The power balance control based on power fluctuations and the resonant current control that can compensate harmonic components have been added to increase the stability of the system. The MATLAB/Simulink simulation was carried out to verify the proposed control method, and the 2-kW single-phase grid-tied PV-ESS smart mobility charger was built and tested.