• KEPCO Journal on Electric Power and Energy
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• v.2 no.3
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• pp.425-431
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• 2016

Supply Capability of the generator, if the maximum demand occurs, refers to the maximum power that can be stably supplied and it is possible to maintain stable power supply to be greater than actual load. However, unexpected power demand and reduction in supply Capability due to stop of unexpected generator in operation can temporarily make a big chaos in power system. In fact, due to a lack of power supply Capability in the country, enforced emergency load adjustment to the September 15, 2011, the circulation power outage has occurred in several cities. As the result, interrupted operation of the elevator and stopped hospital medical equipment led to a great deal of trouble to people's lives, causing a social problem. At that time, it was found that a failed frequency control because of smaller actual supply Capability than that of predicted. The difference was about 1,170 MW with Gas turbine power plant. By accurately calculating the generator supply capability, we can not only grasp the power reserve rate, but also correspond to the time of power supply instability.

• Journal of Magnetics
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• v.19 no.3
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• pp.273-281
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• 2014

This paper presents an innovative design for a low-speed, direct-drive, axial-flux permanent-magnet (AFPM) generator with a coreless stator and rotor that is intended for application to small wind turbine power generation systems. The performance of the generator is evaluated and optimized by means of comprehensive 3D electromagnetic finite element analysis. The main focus of this study is to improve the power output and efficiency of wind power generation by investigating the electromagnetic and structural features of a coreless AFPM generator. The design is validated by comparing the performance achieved with a prototype. The results of our comparison demonstrate that the proposed generator has a number of advantages such as a simpler structure, higher efficiency over a wide range of operating speeds, higher energy yield, lighter weight and better power utilization than conventional machines. It would be possible to manufacture low-cost, axial-flux permanent-magnet generators by further developing the proposed design.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.15-19
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• 2014

As the space of the wind power generator stator end is limited, it is difficult for us to place the inner evaporative cooling system in it. We use the non-overlapping concentrated windings scheme to solve the placing and cooling problem. The characteristic of a 5MW direct-driven permanent magnet generator with non-overlapping concentrated windings were analyzed under no-load, rating-load and short-circuit by (Finite Element Method) FEM for verification of design. We studied the connection methods of the stator windings and designed the end connection member. The heat dissipation of the stator end was simulated by FEM, the result showed that the end cooling could satisfy the wind generator operation needs. These results show that the direct-driven permanent magnet wind power generators with non-overlapping concentrated windings and inner evaporative cooling system can solve the cooling problem of wind power generator, and obtain good performance at the same time.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.245-249
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• 2009

Antarctic King Sejong Station was established in King George Island, the South Pole in 1988, and has been executing the monitoring studies on the change of antarctic natural environment. As an available power, the wind energy generator has been used in the form of hybrid with mainly diesel generator. Because the wind generation power sharply changes by wind energy, it must be careful during the system operation. When the power system becomes stable, the output performance of wind energy generator becomes stable. But, in case of unstable system, the errors frequently occur on the wind energy generator and it badly impacts the power system by output of wind energy generator. The purpose of this paper is to analyze suitability while operating the system of 10kW wind energy generator at Antarctic King Sejong Station, an isolated area, and to analyze the problem and improvements by power quality.

• Proceedings of the KIPE Conference
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• 2004.11a
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• pp.96-100
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• 2004

This paper deals with power quality disturbance generator with phase jump function. The proposed generator can be applied to the performance test of custom power devices. Voltage sag, swell, outage, unbalance and phase jump after outage are provided by the generator. The phase jump operating principle of the generator is described and analysed. The control scheme of the disturbance generator is simple and hardware setup is cost effective compared with the conventional scheme. The usefulness of the generator is verified through simulation and experimental results.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.91-93
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• 1998

In this paper 30 kVA superconducting generator's transient-state electromagnetic analysis by FEM is described. The transient-state analysis by moving air gap technique was performed to analyze its 3 phase sudden short circuit characteristics. External circuit components were connected to generator model with end-winding resistance and inductance.

• Journal of Magnetics
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• v.18 no.3
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• pp.250-254
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• 2013

In this research, the linear electrical generator in wave energy farm utilizing resonance power buoy system is studied. The mechanical resonance characteristics of the buoy and the wave are analyzed to maximize the kinetic energy in a relatively small wave energy area where WRPS is operated. In this research, we chose an analog model of the linear electrical generator of which size is one-hundredth of an actual size of it in WPRS (Wave energy farm utilizing Resonance Power buoy System) prior to verifying the characteristics of actual model of linear electrical generator in WRPS. In addition, the finite element analysis is conducted using commercial electromagnetic analysis software named MAXWELL to examine the electric characteristic of linear generator. Finally, for the verification of dynamic and electric characteristics of linear generator, the prototype was manufactured and the experiments to measure the displacement and the output electric power were performed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.277-277
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• 2009

In this paper, PMPG (Piezoelectric Micro Power Generator) was investigated by ANSYS FEA (Finite Element Analysis) to decrease operating frequency and improve out power. The micro power generator was designed to convert ambient vibration energy to electrical power as a ZnO piezoelectric material. To find optimal model in low vibration ambient, the shape of power generator was changed with different membrane width, thickness, length, and proof mass size. Used the ANSYS modal analysis, bending mode and stress distribution of optimal model were analyzed. Also, the displacement with the frequency range was analyzed by harmonic analysis. From the simulation results, the resonance frequency of optimal model is about 373 Hz and confirmed the possibility of ZnO micro power generator for wireless sensor node applications.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.10
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• pp.497-504
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• 2005

For maximum output power, wind turbines are usually controlled at the speed which is determined by the optimal tip-speed ratio. This method requires information of wind speed and the power conversion coefficient which is varied by the pitch angle control. In this paper, a new maximum output power control algorithm using fuzzy logic control is proposed, which doesn't need this information. Instead, fuzzy controllers use information of the generator speed and the output power. By fuzzy rules, the fuzzy controller produces a new generator reference speed which gives the maximum output power of the generator for variable wind speeds. The proposed algorithm has been implemented for the 3[kW] cage-type induction generator system at laboratory, of which results verified the effectiveness of the algorithm.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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• pp.136-142
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• 2006

A damped sinusoidal electromagnetic pulse generator was designed, fabricated and tested. The pulse generator consisted of an oscillator(a spark gap switch and an initially charged low impedance line) and a high impedance antenna. This generator was capable of producing damped sinusoidal pulses at closure of the spark gap switch. A Marx generator was employed to supply the Pulse generator with high voltage pulses. While the pulse generator was provided with the high voltage pulses of 200kV from the Marx generator, its output power was maximized by controlling the pressure of the gas contained in the spark gap switch. The output power of the damped sinusoidal electromagnetic pulse oscillator was 1.3GW and the amplitude of electric field radiated from the pulse generator was 4kV/m at the range of 25m.