• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.299-305
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• 2015

Global environmental concerns and the ever increasing need of energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Distributed electricity generation is a suitable option for sustainable development thanks to the load management benefits and the opportunity to provide electricity to remote areas. Solar energy being easy to harness, non-polluting and never ending is one of the best renewable energy sources for electricity generation in present and future time. Due to the random and intermittent nature of solar source, PV plants require the adoption of an energy storage and management system to compensate fluctuations and to meet the energy demand during night hours. This paper presents an efficient, economic and technical model for the design of a MPPT based grid connected PV with battery storage and management system. This system satisfies the energy demand through the PV based battery energy storage system. The aim is to present PV-BES system design and management strategy to maximize the system performance and economic profitability. PV-BES (photovoltaic based battery energy storage) system is operated in different modes to verify the system feasibility. In case of excess energy (mode 1), Li-ion batteries are charged using CC-CV mechanism effectively controlled by fuzzy logic based PID control system whereas during the time of insufficient power from PV system (mode 2), batteries are used as backup to compensate the power shortage at load and likewise other modes for different scenarios. This operational mode change in PV-BES system is implemented by State flow chart technique based on SOC, DC bus voltages and solar Irradiance. Performance of the proposed PV-BES system is verified by some simulations study. Simulation results showed that proposed system can overcome the disturbance of external environmental changes, and controls the energy flow in efficient and economical way.

• Journal of the Korean Solar Energy Society
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• v.26 no.2
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• pp.69-77
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• 2006

Photovoltaic is an attractive technology to remote power applications, because of its reliability, low maintenance, and zero fuel requirements. In this paper represents residential PV system based on BESS(battery energy storage system) for managing the electric power, a pattern of daily operation considering the load characteristics of the house, the generation characteristics of PV power, and utility power leveling. For apply to control algorithm, we consider the load on monthly power consumption trend and daily usage pattern. As for the control of the proposed system, to increase the conversion efficiency of the PV power, bidirectional converter is used for MPPT and SPWM inverter. An experimental system is implemented, and some experimental results are provided to demonstrate the effectiveness of the proposed system.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.130-131
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• 2013

In this paper, it suggests offset compensation method of output current in single phase PV-BES system which is connected with grid. The algorithm applied removes grid's frequency ingredient using a notch filter and it extracts only DC offset current. It can reduce problems as saturation of power transformer cause by DC current when it is indoctrinated to grid.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.258-267
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• 2017

The price competitiveness of photovoltaic system (PV system) has risen recently due to the growth of industries, however, it is rarely applied to the greenhouse compared to other renewable energy. In order to evaluate the application of PV system in the greenhouse, power generation and optimal installation area of PV panels should be analyzed. For this purpose, the prediction of the heating and cooling loads of the greenhouse is necessary at first. Therefore, periodic and maximum energy loads of a multi-span greenhouse were estimated using Building Energy Simulation(BES) and optimal installation area of PV panels was derived in this study. 5 parameter equivalent circuit model was applied to analyzed power generation of PV system under different installation angle and the optimal installation condition of the PV system was derived. As a result of the energy simulation, the average cooling load and heating load of the greenhouse were 627,516MJ and 1,652,050MJ respectively when the ventilation rate was $60AE{\cdot}hr^{-1}$. The highest electric power production of the PV system was generated when the installation angle was set to $30^{\circ}$. Also, adjustable PV system produced about 6% more electric power than the fixed PV system. Optimal installation area of the PV panels was derived with consideration of the estimated energy loads. As a result, optimal installation area of PV panels for fixed PV system and adjustable PV system were $521m^2$ and $494m^2$ respectively.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.107-117
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• 2017

Since South Korea started to apply Renewable Portfolio Standard (RPS) in 2012, there have been huge investment for deploying renewable technologies. Recently, the government determined to incentivize battery energy storage system(BESS) with renewable generations in order to induce the improvement of dispatching capability. In this paper, the annual pattern of PV generation based on actual generation data in South Korea is analyzed and the duration curve of capacity factor is proposed in order to provide the simplified analyzing methodology of present support policy for additional BESS installation for decision maker who is responsible for supply and demand planning. With suggested methodology, the range of appropriate BESS size with respect to the variation of system marginal price(SMP) and renewable energy certificate(REC) price can be derived briefly, and decision makers easily evaluate the effect of support scheme. Current policy for BESS installation support present additional BESS-related installation policy may give incentives to developers partially, however, the dependence between BESS size and benefit components (SMP and REC) can limit the deployment of the various portfolios of the BESS. Therefore, when improving the current policy in future, addressing the dependence between the technical aspects of battery size and the benefit components separately by the technical and economical parts is needed to set the suitable compensation rules for the renewable generation and BESS.

• Journal of the Korean Solar Energy Society
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• v.40 no.3
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• pp.21-31
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• 2020

The government mandates gradually zero energy building and Photovoltaic power generation systems installed in buildings are emerging as the most realistic alternative to increase the independence rate of building energy. In this study, we propose a method to reduce the power consumption of households by increasing the PV capacity of balconies and applying the method used the charged electric power stored in batteries after sunset. In order to evaluate the electric power energy savings of the residential BESS, a balcony PV 1.2 kW and a battery pack 2 kWh were installed for 9 houses in 4 apartments in Seoul and Gyeonggi-do. The BESS is charged when the balcony PV is generated electric power, and when solar power generation is finished, it supplies power to the electric appliances connected to the load. As a result of installing the solar PV module 1.2 kW and 2 kWh class BESS for 3 households located in Seoul and Gyeonggi-do, the average electric power consumption saving rate was 40%. The reduction in electricity consumption in the case of zero generation surplus power by maximizing the utilization rate of BESS has been improved to about 53%. Therefore, in order to increase the self-sufficiency rate of electric energy in apartment houses, it is effective to increase the solar photovoltaic capacity of the balcony and apply the residential BESS. In the future, it is believed that the balcony PV and home BESS will play a key role in achieving mandatory zero-energy housing.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1176-1185
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• 2016

This paper proposes a new output voltage control scheme based on the SoC variation of the battery energy storage system (BESS) applicable for the stand-alone DC microgrid. The proposed control scheme provides relatively lower variation of the DC grid voltage than the conventional droop method. The performance of proposed control scheme was verified through computer simulations for a typical stand-alone DC microgrid which consists of BESS, photo-voltaic (PV) panel, engine generator (EG), and DC load. A scaled hardware prototype for the stand-alone DC microgrid with DSP controller was set up in the lab, and the proposed control algorithm was installed in the DSP controller. The test results were compared with the simulation results for performance verification and actual system implementation.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1072-1079
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• 2014

This paper introduces a coordinated droop control for the stand-alone DC micro-grid, which is composed of photo-voltaic generator, wind power generator, engine generator, and battery storage with SOC (state of charge) management system. The operation of stand-alone DC micro-grid with the coordinated droop control was analyzed with computer simulation. Based on simulation results, a hardware simulator was built and tested to analyze the performance of proposed system. The developed simulation model and hardware simulator can be utilized to design the actual stand-alone DC micro-grid and to analyze its performance. The coordinated droop control can improve the reliability and efficiency of the stand-alone DC micro-grid.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1709-1717
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• 2015

In remote islands PV (Photo Voltaic) panel with BESS (Battery Energy Storage System) supplies electric power to the customers in parallel operation with EG (Engine Generator) to save fuel consumption and to mitigate environmental load. BESS operates in voltage control mode when it supplies power to the load alone, while it operates in current control mode when it supplies power to the load in parallel with EG. This paper proposes a smooth mode change scheme from current control to voltage control of BESS by adding proper initial value to the integral part of voltage control, and a smooth mode change scheme from voltage control to current control by tracking the EG output voltage to the BESS output voltage using PLL (Phase-Locked Loop). The feasibility of proposed schemes was verified through computer simulations with PSCAD/EMTDC, and the feasibility of actual hardware system was verified by experiments with scaled prototype. It was confirmed that the proposed schemes offer a seamless operation in the stand-alone power system in remote islands.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1355-1363
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• 2015

In order to maintain customer voltage within allowable limit($220{\pm}13V$), tap operation of SVR(step voltage regulator) installed in primary feeder could be carried out according to the scheduled delay time(30 sec) of SVR. However, the compensation of BESS(battery energy storage system) is being required because the customer voltages during the delay time of SVR have a difficultly to maintain within allowable limit when PV system is interconnected with primary feeder. Therefore, this paper presents modeling of SVR to regulate voltage with the LDC(line drop compensation) method and modeling of BESS to control active and reactive power bi-directionally. And also, this paper proposes the coordination control modeling between BESS and SVR in order to overcome voltage problems in distribution system. From the simulation results based on the modeling with the PSCAD/EMTDC, it is confirmed that proposed modeling is practical tool for voltage regulation analysis in distribution system.