• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.121-127
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• 2012

An electric power compensation system for a DC transmission system with an integrated wind turbine generator is proposed. The proposed compensation system consists of a synchronous generator and a duplex reactor. This apparatus is connected to the sending-end circuit of the DC transmission system. A set of steady-state equations of the system is first derived. Then, the effect of the duplex reactor, which can eliminate the sending-end grid current distortion due to commutation of the converter, is explored. The relationships among power at the sending-end circuit are also revealed. It is shown that fluctuations in the sending-end grid power due to changes in wind velocities are compensated with the proposed system. Finally, the effects of the sending-end grid conditions on the steady-state characteristics of the system are studied.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1756-1758
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• 2005

This paper deals with the power conversion and design of permanent magnet generator for wind power applications. This paper derives analytical solutions for open-circuit field, armature reaction field, torque, back-emf, inductance and resistance of permanent magnet generators for wind power applications. And then, by presenting the variation of torque according to design parameters and by applying restrict conditions to it, we determine proper design parameter appropriate to rated power and speed. Finally, this paper also presents power conversion system resonable in wind power applications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.6
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• pp.82-89
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• 2011

Reactive power support is considered to be necessary for dealing with a voltage stability issue with wind turbine system employing squirrel-cage induction generator(SCIG). This paper analyses steady-state characteristics of the SCIG wind turbine system by simulating torque-slip characteristics of SCIG with respect to variations of interconnecting network strength and generator terminal voltage. It also presents dynamics analysis of SCIG wind turbine system on Simulink to investigate the impact of static var compensator(SVC) and static synchronous compensator(STATCOM) on transient stability enhancement. It analysed transient stability with varying fault duration times and compared the transient stability characteristics with varying rated capacities of SVC and STATCOM. It is shown that the STATCOM has a better performance and reactive power support compared to SVC.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.379-384
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• 2004

A prototype of 750 kW direct-drive wind turbine generator system, KBP-750D is under development in Korea. For the gearless, direct-drive prototype a synchronous generator with permanent magnets has been developed. The upwind 3-blade type machine employs variable speed and pitch control. The operating ranges of wind and rotor speed are 3 to 25 m/s and 9 to 25 rpm, respectively. The tip speed ratio of rotor blade is 7.5, designed for power coefficient 0.47, The blade pitch and torque are controlled with the predefined torque-speed curve according to the conditions of wind and public electric grid. This paper describes the outlines of primary components of KBP-750D.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1820-1827
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• 2012

This paper is to present a new method of cogging torque reduction for axial flux PM machines of multiple rotor surface mounted magnets. In order to start softly and to run a power generator even the case of weak wind power, reduction of cogging torque is one of the most important issues for a small wind turbine, Cogging torque is an inherent characteristic of PM machines and is caused by the geometry shape of the machine. Several methods have been already applied for reducing the cogging torque of conventional radial flux PM machines. Even though some of these techniques can be also applied to axial flux machines, manufacturing cost is especially higher due to the unique construction of the axial flux machine stator. Consequently, a simpler and low cost method is proposed to apply on axial flux PM machines. This new method is actually applied to a generator of 1.0kW, 16-poles axial flux surface magnet disc type machine with double-rotor-single-stator for small wind turbine. Design optimization of the adjacent magnet pole-arc which results in minimum cogging torque as well as assessment of the effect on the maximum available torque using 3D Finite Element Analysis (FEA) is investigated in this design. Although the design improvement is intended for small wind turbines, it is also applicable to larger wind turbines.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2307-2309
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• 2004

This paper presents a modeling and simulation of a fuzzy controller for maximum power extraction of a grid-connected wind energy conversion system with a link of a rectifier and an inverter. It discusses the maximum power control algorithm for a wind turbine and proposes, in a graphical form, the relationships of wind turbine output, rotor speed, power coefficient, tip-speed ratio with wind speed when the wind turbine is operated under the maximum power control. The control objective is to always extract maximum power from wind and transfer the power to the utility by controlling both the pitch angle of the wind turbine blades and the inverter firing angle. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation method. The simulation results performed on MATLAB will show the variation of generator's rotor angle and rotor speed, pitch angle, and generator output.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.820-826
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• 2014

It is well known that energy generated by a wind generator (WG) depends on the wind resources at the installation site. In other words, a WG installed in a high wind speed area can produce more energy than that in a low wind speed area. However, a WG installed at a low wind site can produce a similar amount of energy to that produced by a WG installed at a high wind site if the WG is designed with a rated wind speed corresponding to the mean wind speed of the site. In this paper, we investigated the power curve of a WG suitable for Korea's southwestern coast with a low mean wind speed to achieve a high capacity factor (CF). We collected the power curves of the 11 WGs of the 6 WG manufacturers. The probability density function of the wind speed on Korea's southwestern coast was modeled using the Weibull distribution. The annual energy production by the WG was calculated and then the CFs of all of the WGs were estimated and compared. The results indicated that the WG installed on the Korea's southwestern coast could obtain a CF higher than 40 % if it was designed with the lower rated speed corresponding to the mean wind speed at the installation site.

• New & Renewable Energy
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• v.16 no.2
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• pp.14-19
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• 2020

Recently, a project to build a carbon zero island with no carbon emissions has been carried out by replacing diesel generators with renewable energy sources in island areas where diesel generators supplied local loads as independent systems. To minimize damage to the lives of islanders, low noise wind generators should be installed by adjusting the rated speed. In islands with low loads, wind turbines that are more efficient than medium-sized wind turbines should be installed. In this study, the generator field analysis and characteristics were analyzed to develop 230 kW-class low wind medium-wind turbine technology. The electromagnetic field analysis program used Maxwell. As a result, the cogging torque was reduced, and the initial maneuver wind speed and loss value were lowered. Hence, the output amount was increased with high efficiency.

• Journal of Industrial Technology
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• v.31 no.A
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• pp.123-128
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• 2011

In this study, procedures, a power performance testing system of Wind Turbine System Research Center of Kangwon National University is introduced. Test prodedures and results are presented on a stand-alone vertical-axis 200W wind turbine manufactured by Geum-Poong Energy Inc.. Power performance test is performed according to IEC standard. The test results are compared with the power performance standard. Also, the effects of normalization and disturbed sectors are considered.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.6
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• pp.989-995
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• 2013

Unlike fossil-or nuclear fuel-based power generation, wind power generation using inexhaustible wind energy is a pollution-free, hazardless power generation method. In this study, ultrasound thermography is used for fabricating specimens of wind power generator bearings and wind power generator supplement flanges, and an optimally designed ultrasound horn and ultrasound excitation system are used for detecting damage to part materials of a wind power generation setup. In addition, thermal flow analysis and ultrasonic thermography imaging are comparatively analyzed for improving the detection reliability in terms of surface and internal defects of part materials and for verifying the developed system's field applicability and reliability.