• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.668-672
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• 2001

The utility interactive sinewave modulated inverter for the solar photovoltaic (PV) power conversion and conditioning with a new high frequency pulse modulated link is presented for domestic residential applications. As compared with the conventional full-bridge hard switching PWM inverter with a high frequency AC link, the simplest single-ended quasi-resonant soft switching sinewave modulated inverter with a duty cycle pulse control is implemented, resulting in size and weight reduction and low-cost. This paper presents a prototype circuit of the single-ended zero voltage soft switching sinewave inverter for solar power conditioner and its operating principle. In addition, this paper proposes a control system to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed from an experimental point of view. A newly developed interactive sinewave power processor which has $92.5\%$ efficiencty at 4kW output is demonstrated. It is designed 540mm-300mm-125mm in size, and 20kg in weight.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.250-255
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• 2009

This study was analyzed the long term performance of the demonstration system for solar energy desalination in Jeju. we used a solar thermal system as heat source of the single-stage fresh water generator with plate-type heat exchangers and a photovoltaic power system as electric source for hydraulic pumps. The demonstration system was designed and installed at Jeju-island in 2006. The system was comprised of the desalination unit with daily fresh water capacity designed as $2m^3$ a $120m^2$ evacuated tubular solar collector to supply the heat, a $6m^3$ heat storage tank, and a 5kW photovoltaic power generation to supply the electricity of hydraulic pumps for the heat medium fluids. Through the operation during about 3 years, In a clear day more than $400W/m^2$, the daily fresh water showed to produce more than about 500liter, and from January, 2007 to March, 2009 for 3 years, solar irradiance daily averaged was measured $370W/m^2$, the daily fresh water yield showed that can be produced about 330liter.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.189-192
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• 2008

The solar photovoltaic Power generator can get more power with the higher solar radiation quantity. However, if the higher solar radiation quantity on cell becomes high temperature, the efficiency of generate will be reduced. To install cooling system for this kind of device can be the way to solve high temperature problem on cell but another problems after install it such as increasing of solar generated quantity problem, cost to install cooling system and cost to be maintained cooling system weren't discussed to practical use this system. So the present paper described about effect and commercial business possibility of cooling system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.229-235
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• 2019

A floating photovoltaic generation system is a new concept that combines existing photovoltaic generation technology with floating technology. This is installed in the water not on conventional land and a building. The system is designed as a unit module type that can be connected to other modules according to the power generation capacity, thereby forming a large-scale power generation facility. As a renewable energy source, it is composed of a floating structure, mooring device, photovoltaic power generation facility, and underwater cable. Because this system is installed outdoors, the effect of the wind load on the structure is very large. In this study, the wind loads most affected on the floating photovoltaic generation structure were obtained by computational fluid dynamic analysis. The flow characteristics and wind loads were analyzed for a range of wind orientations and angles of inclination. The analysis showed the position and magnitude of the maximum wind load to the wind direction and the flow characteristics around the solar panel and floating system. The wind load increased with increasing angle of inclination of the panel to the ground.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1483-1493
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• 2018

Recently, more power facilities are needed to cope with the increasing electric demand. However, the additional construction of generators, transmission and distribution installations is not easy because of environmental problems and citizen's complaints. Under this circumstance, a microgrid system with distributed renewable resources emerges as an alternative of the traditional power systems. Moreover, the configuration of power system changes with more DC loads and more DC installations. This paper is written to introduce an idea of a genetic algorithm-based solution to determine the optimal capacity of the distributed generators depending on the types of system configuration: AC-link, DC-link and Hybrid-link types. In this paper, photovoltaic, wind turbine, energy storage system and diesel generator are considered as distributed generators and the feasibility of the proposed algorithm is verified by comparing the calculated capacity of each distributed resource with HOMER simulation results for 3 types of system configuration.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1408-1414
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• 2015

The renewable energies such as photovoltaic power, wind power and biomass have grown to a greater extent as decarbonization techniques. The renewable energies are interconnected to power systems (or electrical grids) in order to increase benefits from economies of scale, and the extra attention is focused on the Grid Code. A grid code defines technical parameters that power plants must meet to ensure functions of power systems, and the grid code determined by considering power system characteristics is various across the country. Some TSO (Transmission System Operator) and ISO (Independent System Operator) have issued grid code for wind power and the special requirements for offshore wind farm. The main purpose of the above grid code is that wind farm in power systems has to act as the existing power plants. Therefore wind farm developer and wind turbine manufacturer have great difficulty in grasping and meeting grid code requirements. This paper presents the basic understanding for grid codes of developed countries in the wind power and trends of those technical requirements. Moreover, in grid code viewpoint, the active power control of wind power is also discussed in details.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1383-1389
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• 2013

There were telecommunication noise and malfunctions of the electronic devices occurred over a wide area due to the high harmonic voltage and/or current levels of the Back-to-back converter in the DFIG wind power system even though the magnitude of all harmonics is within the international standards. The triangular carrier signals of the PWM used in the power converter system is related to the telecommunication noise because they are in the range of audible frequencies and amplified by a variety of the standing waves that were excited by harmonic voltage sources in the weak grid system such as a long distance distribution transmission lines. This paper describes the characteristics of the harmonics in the wind turbine-generator, numerical analysis and simulation of the harmonics resonance phenomena in the distribution lines as well as measuring induced voltage of the telecommunication lines in parallel with power lines in order to verify the root cause of the telecommunication noise. These noise problems can occur in a wind turbine power system with a non-linear converter at any time, as well as photovoltaic power system. So, the preliminary review of suitable filter devices and switching frequencies of the PWM have to be required by considering the stability of the controller at the design stage but as part of the measures the effect of the telecommunication cable shields was analyzed by comparing the measured data between multi-conductor with/without shields so as to attenuate the sources of the harmonics voltage induced into the telecommunication lines and to apply the most cost-effective measures in the field.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.12B no.1
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• pp.24-30
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• 2002

The developments of the solar and the wind power energy are necessary since the future alternative, energies that have no pollution and no limitation are restricted. Currently power generation system of MW scale has been developed, but it still has a flew faults with the weather condition. In order to solve these existing problem combined generation system of photovoltaic(400W) and wind power generation system(400W) was suggested. It combines wind power and solar energy to have the supporting effect from each other. However, since even combined generation system cannot always generate stable output with ever-changing weather condition, power storage apparatus that uses elastic energy of spiral spring to combined generation system was also added far the present study. In an experiment, when output of combined generation system gets lower than 12V(charging voltage), power was continuously supplied to load through the inverter by charging energy obtained from generating rotary energy of spiral spring operates in small scale generator.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1643-1653
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• 2014

This paper presents the design and implementation of a wind-solar hybrid power system for LED street lighting and an isolated power system. The proposed system consists of photovoltaic modules, a wind generator, a storage system (battery), LED lighting, and the controller, which can manage the power and system operation. This controller has the functions of maximum power point tracking (MPPT) for the wind and solar power, effective charging/discharging for the storage system, LED dimming control for saving energy, and remote data logging for monitoring the performance and maintenance. The proposed system was analyzed in regard to the operation status of the hybrid input power and the battery voltage using a PSIM simulation. In addition, the characteristics of the proposed system's output were analyzed through experimental verification. A prototype was also developed which uses 300[W] of wind power, 200[W] of solar power, 60[W] LED lighting, and a 24[V]/80[Ah] battery. The control system principles and design scheme of the hardware and software are presented.

• Korean Management Science Review
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• v.30 no.2
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• pp.97-106
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• 2013

Of the new and renewable energies currently being pursued domestically, wind energy, together with solar photovoltaic energy, is a new core growth driver industry of Korea. As of May 2012, 33 wind farms at a capacity of 347.8MW are in operation domestically. The purpose of this study was to compare and analyze how efficiently each operational wind farm is utilizing its power generation capacity and the weather resource of wind. For this purpose, the study proceeded in 3 phases. In phase 1, ANOVA analysis was performed for each wind farm, thereby categorizing farms according to capacity, region, generator manufacturer, and quantity of weather resources available and comparing and analyzing the differences among their operating efficiency. In phase 2, for comparative analysis of the operating efficiency of each farm, Data Envelopment Analysis (DEA) was used to calculate the efficiency index of individual farms. In the final phase, phase 3, regression analysis was used to analyze the effects of weather resources and the operating efficiency of the wind farm on the power generation per unit equipment. Results shows that for wind power generation, only a few farms had relatively high levels of operating efficiency, with most having low efficiency. Regression analysis showed that for wind farms, a 1 hour increase in wind speeds of at least 3m/s resulted in an average increase of 0.0000045MWh in power generation per 1MW generator equipment capacity, and a unit increase in the efficiency scale was found to result in approximately 0.20MWh power generation improvement per unit equipment.