• The KSFM Journal of Fluid Machinery
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• v.13 no.2
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• pp.36-40
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• 2010

Tidal current power system is the energy converter which converts the kinetic energy of tidal stream into electric energy. The performance of the rotor which initially converts the energy is determined by various design factors and it should be optimized by the ocean environment of the field. Flow direction changes due to rise and fall of the tides, but horizontal axis turbine is very sensitive to direction of flow. To investigate the rotor performance considering the interaction problems with incidence angle of flow, series of experiments have been conducted. The results and findings are summarized in the paper.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.730-734
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• 2007

National projects on renewable energy and new energy are driven more actively than ever in many countries for the exhaustion of fossil fuel energy from the turn of the century. Such activities began to spread out in railway industry with centering around west European countries. Electric energy is generated on the hybrid vehicle itself, which contributes to reduction of the cost for construction of the infrastructure required for the supply of electric power. Hybrid tram is mainly composed of propulsion system to control electric energy, automatic guidance system to control steering and operation, and central vehicle unit to control and monitor major electronic devices. Generation and supply of electric power are made by the combination of engine generator and battery, or fuel cell and super capacitor.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.246-249
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• 2007

The application of photovoltaics into building as integrated building components has been paid more attention worldwide. Photovoltaics or solar electric modules are sol id state devices, directly converting solar radiation into electricity; the process does not require fuel and any moving parts, and produce no pollutants. And the prefab building method is very effective because the pre- manufactured building components is simply assembled to making up buildings in the construction fields especially the sandwich panel. So, this paper describes a design and performance test of the 10kW poly metal pv module(pmpp) system. It is concluded that the prediction of BIPV system's performance should be based on the more accurate PV module installation.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.520-522
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• 2006

According to the second scheme of the Korean Government about technology development, utilization and popularization of new renewable energy, the continuous growth of distributed resources are expected. But there is a few paper about recloser and sectionalizer coordination and protection scheme in distribution system interconnected a number of distributed resources. In this paper, it is dealt with that recloser and sectionalizer coordination at the cases concerned with position among protection devices. Adding distributed resource, the problems of each case are investigated through simulation.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.1-5
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• 2014

When renewable sources are connected to the distribution network in the form of a distributed generators(DGs), the effect of intermittent output appears as voltage fluctuation. The surplus power at the consumer ends results in the reverse power flow to the distribution network. This reverse power flow causes several problems to the distribution network such as overvoltage. Application of the reactive power control equipment and power flow control by means of BTB inverter have been suggested as the general solutions to overcome the overvoltage, but they are not economically feasible since they require high cost devices. Herein, we suggest the feeder loop line switch control method to solve the problem.

• Journal of Power Electronics
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• v.12 no.3
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• pp.487-494
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• 2012

A new low cost high power density photovoltaic power conditioning system (PV PCS) with an energy storage system is proposed in this paper. Its high power density and cost effectiveness can be achieved through the unification of the maximum power point tracker and the battery charger/discharger. Despite the reduced power stage, the proposed system can achieve the same performance in terms of maximum power point tracking and battery charging/discharging as the conventional system. When a utility power failure happens, the proposed system cannot perform maximum power point tracking at the UPS mode. However, the predetermined battery voltage near the maximum power point of the PV array can effectively generate a reasonable PV power even at the UPS mode. Therefore, it features a simpler structure, less mass, lower cost, and fewer devices. Finally, to confirm the operation, validity, and features of the proposed system, a theoretical analysis and experimental results from a single phase AC 220Vrms/1.5kW prototype are presented.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.47.2-47.2
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• 2011

High-efficient transparent conductive oxide (TCO) film-embedding Si heterojunction solar cells were fabricated. An improved crystalline indium-tin-oxide (ITO) film was grown on an Al-doped ZnO (AZO) template upon hetero-epitaxial growth. This double TCO-layered Si solar cell provided significantly enhanced efficiency of 9.23 % as compared to the single TCO/Si devices. The effective arrangement of TCO films (ITO/AZO) provides a good interface, resulting in the enhanced photovoltaic performances. It discusses TCO film arrangement scheme for efficient TCO-layered heterojunction solar cells.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.139.1-139.1
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• 2011

Electric vehicle use independent electricity of high voltage. if isolation of electricity is destructed, devices and people are considerably damaged. Therefore, detection of ground fault is necessary for electric vehicle. As the existing detection method of ground fault can not detect ground fault when isolation of both positive side and negative side of electricity is destructed, and change of voltage of electricity. This paper proposed detection method for ground fault of both two sides of electricity and change of voltage. The proposed method is verified by analysis of equivalent circuit.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.704-706
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• 2005

According to the second scheme of the Korean Government about technology development, utilization and popularization of new ${\cdot}$ renewable energy, the continuous growth of distributed resources are expected. But there is a few paper about recloser and sectionalizer coordination and protection scheme in distribution system interconnected a number of distributed resources. In this paper, it is dealt with that recloser and sectionalizer coordination at the cases concerned with position among protection devices. Adding distributed resource, the problems of each case are investigated through simulation.

• Journal of Power Electronics
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• v.15 no.1
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• pp.96-105
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• 2015

In recent years, the multilevel converters have been given more attention due to their modularity, reliability, failure management and multi stepped output waveform with less total harmonic distortion. This paper presents a novel symmetric multilevel inverter topology with reduced switching components to generate a high quality stepped sinusoidal voltage waveform. The series and parallel combinations of switches in the proposed topology reduce the total number of conducting switches in each level of output voltages. In addition, a comparison between the proposed topology with another topology from the literature is presented. To verify the proposed topology, the computer based simulation model is developed using MATLAB/Simulink and experimentally with a prototype model results are then compared.