• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.19-21
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• 2008

Renewable energy resources such as wind, wave, solar, micro hydro, tidal and biomass etc. are becoming importance stage by stage because of considering effect of the environment. Solar energy is one of the most successful sources of renewable energy for the production of electrical energy following wind energy. And, the solar/photovoltaic cell generators can not make two-state model as conventional generators, but should be modeled as multi-state model due to solar radiation random variation. The method of obtaining reliability evaluation index of solar cell generators is different from the conventional generators. This paper presents a basic study on reliability evaluation of power system considering solar cell generators with multi-states.

• Current Photovoltaic Research
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• v.4 no.2
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• pp.48-53
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• 2016

We report the effect of physical load on the stability of organic solar cells under physical loads. The active layers in organic solar cells were fabricated with bulk heterojunction films (BHJ) films of poly (3-hexylthiophene) and phenyl-$C_{61}$-butyric methyl ester. The loading time was varied up to 60 s by keeping the physical load constant. Results showed that the open circuit voltage was not influenced by the physical load but other solar cell parameters were sensitive to the loading time. The fill factor was very slightly increased at 15 s, while short circuit current density was well kept for 30 s. The power conversion efficiency was reasonably maintained for 45 s but became significantly decreased by the continuous loading for 60 s.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.2
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• pp.80-85
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• 2004

This paper reports the performance of a CB (Circuit Breaker) and converter for the battery operated Wind-PV (Photovoltaic) system. For this purpose, a fluctuating reduction controller for an electric generation hybrid (wind+PV) system is suggested. The method operates a wind turbine, PV, CB, converter and battery. Integration of wind and PV sources, which are generally complementary, usually reduce the capacity of the battery. Also, CB controls the overvoltage of the generation system. The objective is to control the operation of the converter and the CB and reduce power fluctuation. This paper includes discussion on system performance, power quality, fluctuation and effect of the randomness of the wind.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.539-545
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• 2012

Due to merits cost and efficiency, the transformer-less type photovoltaic (PV) inverters have been popularized in the solar market. However, the leakage current flowing through a parasitic capacitor between PV array and ground can cause adverse effect in the transformer-less PV system. In this paper, a bi-directional PV inverter with high efficiency and low noise is proposed for the PV system with an energy storage device. The proposed inverter is a transformer-less type and performs the bi-directional power control between dc sources and grid with high efficiency. In addition, the proposed inverter can suppress the leakage current and obtain low noise characteristic. Finally, 3-kW prototype was implemented to confirm validity of the proposed inverter.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.276-281
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• 2012

Power semiconductor devices are widely used as high voltage applications to inverters and motor drivers, etc. The blocking voltage is one of the most important parameters for power semiconductor devices. Generally most of field effect concentrations shows on the edge of power devices. Can be improve the breakdown characteristic using edge termination technology. In this paper, considering the variables that affect the breakdown voltage and optimization of parameters result for 600 V Super Junction MOSFET Field ring.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.270-275
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• 2012

Power MOSFET(metal oxide silicon field effect transistor) operate voltage-driven devices, design to control the large power switching device for power supply, converter, motor control, etc. But on-resistance characteristics depending on the increasing breakdown voltage spikes is a problem. So 600 V planar power MOSFET compare to 1/3 low on-resistance characteristics of super junction MOSFET structure. In this paper design to 600 V planar MOSFET and super junction MOSFET, then improvement of comparative analysis breakdown voltage and resistance characteristics. As a result, super junction MOSFET improve on about 40% on-state voltage drop performance than planar MOSFET.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.45-48
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• 2002

This paper proposes a grid-connected inverter using the negative conductance of PV power system, which has four IGBTs and simple controller. Most of modern electric loads generate the current harmonics and the line voltage distortion. The new solar-to-ac converter(STAC) provides by emulating a negative conductance load to the line voltage, so the current harmonics from STAC is canceled the effect of the harmonics from other loads. As a result, the line voltage distortion is decreased. The proposed system have low cost, small size, and light weight compared to conventional photovoltaic converter

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.304-308
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• 2002

This paper studies stand-alone photovoltaic array for solar lighting lamp. The solar lighting lamp has PV modules, batteries. and charge & discharge system. The charge efficiency is improved for the control of each battery which is divided the charge from the discharge to change the structure of existing solar lighting lamp charge & discharge system. so, the charge and discharge times are reduced of 50%. and the depth of discharge control can be controlled in the discharge cut off voltage. This can be effective of battery use. If a battery is out of order, this system can be executed for a regular period. so we saved the repair cost and developed of system's stabilization. It is possible economical effect to apply for solar lighting lamp used photovoltaic array.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.489-489
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• 2011

The effect of Si quantum dots for solar cell appications was investigated. The 5 ~ 10 nm Si nanoparticle was fabricated on p-type single and poly crystalline wafer by magnetron sputtering and laser irradiation process. Scanning electron microscopy (SEM), atomic force measurement (AFM) and transmission electron microscopy (TEM) images showed that the Si QDs array were clearly embedded in insulating layer ($SiO_2$). Photoluminesence (PL) measurements reliably exhibited bandgap transitions with every size of Si QDs. The photo-current measurements were showed different result with size of QD and number of superlattice.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.316-318
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• 1994

Photovoltaic is considered to be one of the most promising technologies which can greatly contribute to future energy supply because or a large, secure, essentially inexhaustible and broadly available resource -sunlight. This paper analyzes reduction of synthetic power peak value through weather data and quantity or generation. This explanation and estimations analyses grid connected power system.