• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.602-608
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• 2009

In this thesis, output voltage, current and power of solar module were classified by irradiation from data of overall operating characteristics collected for one year in order to manage efficient photovoltaic generation system and deliver maximum power. In addition, from these data, correlations between irradiation of photovoltaic cell and amount of power given by photovoltaic cell was quantitatively examined to deduce optimization of the design and construction of photovoltaic generation system. As I-V characteristics according to a temperature range of 10~50[$^{\circ}C$], the area of I-V characteristics were increased with an increase in temperature. Since this area corresponds to the power, output power is thought to have increased with temperature. As output power characteristics according to a temperature range of 10~50[$^{\circ}C$], output power was increased with an increase in temperature. Since output power increases with temperature increase, the result corresponds well to the related equation on temperature and output power. As I-V characteristics according to a irradiation range of 100~900 [$W/m^2$], voltage and current were increased with an increase in irradiation. The result is thought of as an increase in output power with increasing irradiation. As output power characteristics according to a irradiation range of 100~900 [$W/m^2$], output power was increased with increasing irradiation. This result corresponds well to the related equation on irradiation and output power.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1122_1123
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• 2009

Doubly Fed Induction Generator (DFIG) used in variable speed constant frequency wind energy generation system can capture wind energy with the highest efficiency by using the stator flux oriented vector control method. This paper sets up a DFIG modeling of wind generation system in PSCAD/EMTDC to simulate the operational performance with wind speed variation. In order to achieve the characteristics of the maximum utilization of wind power, this paper uses the vector control technology to track largest wind power and the independent control of generator active and reactive power.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.3
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• pp.378-386
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• 2012

For reduction of the amount of CO2 emitted from ships, power generation characteristics of two power generation systems consisting of a high-efficiency permanent magnet synchronous generator and diode bridge rictifiers are discussed in this paper. One of the discussed systems has three-phase stator windings, and the other has two sets of three-phase (six-phase) stator windings to reduce pulsation in the electromagnetic torque and DC current. Experimental results reveal that the power generation efficiency of the system having six-phase stator windings is higher than that of the system having three-phase stator windings for a light load. The maximum power generation efficiency of the system having six-phase stator windings is almost the same as that of the system having three-phase stator windings. For the electromagnetic torque of the system having six-phase stator windings, the width of pulsation is about one-fifth compared to the system having three-phase stator windings.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.74-80
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• 2006

This paper describes a solar energy conversion strategy is applied to grid-connected single phase inverter by the maximum power point of conversion strategy. The maximum power point of tracking is controlled output power of PV(photovoltaic)modules, based on generated circuit control MOSFET switch of two boost converter for a connected single phase inverter with four IGBT's switch in full bridge. The generation control circuit allows each photovoltaic module to operate independently at peak capacity, simply by detecting of the output power of PV module. Furthermore, the generation control circuit attenuates low-frequency ripple voltage. which is caused by the full-bridge inverter, across the photovoltaic modules. The effectiveness of the proposed inverter system is confirmed experimentally and by means of simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2064-2075
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• 2011

In this paper, robust multi-level perturbation and observation (MLPO) maximum power point tracking (MPPT) control are presented of the environmental change including the solar radiation and temperature. Because the maximum power point of the Photovoltaic (PV) is changing according to the solar radiation and temperature, the technology which traces the maximum power point in order to increase the power efficiency is recognized as the very important part. The general requirement for the MPPT is that system is simple, the cost is inexpensive, the PV tracking function and output change are small. Conventional perturbation and observation (PO) method is a simple system but there is the disadvantage that an efficiency of system becomes low. In addation, the incremental conductance (IC) control is required expensive CPU because of a large of calculations. In order to solve this problem, in this paper, the MLPO MPPT control using the method diversifying the step size according to the environment condition is presented. The validity of the MLPO method presenting from this paper is proved through analyzing the solar power generation output error at the steady state.

• Journal of Power Electronics
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• v.16 no.2
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• pp.666-674
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• 2016

In this paper, a high efficiency satellite electrical power supply system is proposed. The increased efficiency of the power supply system allows for downscaling of the solar array and battery weight, which are among the most important satellite design considerations. The satellite power supply system comprises two units, namely a generation unit and a storage unit. To increase the efficiency of the solar array, a maximum power point tracker (MPPT) is used in the power generation unit. In order to improve the MPPT performance, a novel algorithm is proposed on the basis of the hill climbing method. This method can track the main peak of the array power curve in satellites with long duration missions under unpredicted circumstances such as a part of the array being damaged or the presence of a shadow. A lithium-ion battery is utilized in the storage unit. An algorithm for calculating the optimal rate of battery charging is proposed where the battery is charged with the maximum possible efficiency considering the situation of the satellite. The proposed system is designed and manufactured. In addition, it is compared to the conventional power supply systems in similar satellites. Results show a 12% increase in the overall efficiency of the power supply system when compared to the conventional method.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3365-3370
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• 2007

We developed micro power generation system using piezoelectric materials. In our system, the ambient vibrating energy is converting to electric energy by deflection of piezoelectric beams. The system consists of energy generating parts, converting enhancement parts, electric regulation and charging parts, and interface with small-energy-consuming mobile devices. The geometry of piezoelectric beams, the source of vibrating energy, and the electric load of target application determine the characteristics of generating electric power, such as impedance, voltage, current and power density. Therefore, we made a model for analysis of generating power with given information such as piezoelectric materials, geometry, vibration type, and mass. With this model, we can calculate capacitance of piezoelectric beams, generating voltage, current, and power. To obtain maximum energy transfer efficiency, we approached this study in the view of material, electrical, and mechanical engineering

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.93.1-93.1
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• 2011

To obtain higher power efficiency of Residential Power Generation System(RPG), it is needed to operate system on optimized stoichiometric ratio of fuel and air. In this paper, optimizing stoichiometric ratio of fuel/air is conducted through systematic experiments and modeling. Based on fundamental principles and experimental data, constraints are chosen. Using these stoichiometric ratios as decision variables, maximum power efficiency of system could be found. As a result of research, power efficiency of RPG system is improved.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.54-56
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• 2005

The paper proposes the solar photovoltaic power generation system method for photovoltaic system to solve the power shortage due the sudden power demand. So that supplied electric power to system at appearance during surplus electric power minute and unit moment link driving with common use system is available, digital PLL circuit system voltage through composition and phase of solar photovoltatic power generation system to do synchronization do. Feed forward controller was applied to get fast current response Solar cell that is changed by solar radiation always kept the maximum output when it used Step up chopper. The dynamic character had checked through simulation used Matlab Sumulink and confirmed through an experiment.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.8
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• pp.308-316
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• 1985

This paper proposes an analytic tool for long-term generation expansion planning based on the maximum principle. Many research works have been performed in the field of generation expansion planning. But few works can be found with the maxinmum principle. A recently published one worked by professor Young Moon Park et al. shows remarkable improvements in modeling and computation. But this modeling allows only thermal units. This paper has extended Professor Park's model so that the optimal pumped-storage operation is taken into account. So the ability for practical application is enhanced. In addition, the analytic supply-shortage cost function is included. The maximum principle is solved by gradient search due to its simplicity. Every iteration is treated as if mathematical programming such that all controls from the initial to the terminal time are manipulated within the same plane. Proposed methodology is tested in a real scale power system and the simulation results are compared with other available package. Capability of proposed method is fully demonstrated. It is expected that the proposed method can be served as a powerful analytic tool for long-term generation expansion planning.