• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.491-494
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• 2009

This paper introduces the design concepts and characteristics of WinDS3000$^{TM}$ which is a trade mark of Doosan's 3MW offshore/onshore wind turbine. WinDS3000$^{TM}$ has been designed in consideration of high RAMS (Reliability, Availability, Maintainability and Serviceability) and cost effectiveness for the TC Ia condition in GL guideline. An integrated drive train design with an innovative three-stage gearbox has been introduced to minimize nacelle weight of the wind turbine and to enhance a high reliability for transmission. A permanent magnet generator with full converter system has been introduced to get higher efficiency in part load operation, and grid friendliness use of 50 Hz and 60 Hz grid. A pitch regulated variable speed power control with individual pitch system has been introduced to regulate rotor torque while generator reaction torque can be adjusted almost instantaneously by the associated power electronics. An individual pitch control system has been introduced to reduce fatigue loads of blade and system. The wind turbine has been also equipped with condition monitoring and diagnostic systems in order to meet maintainability requirements. And internal maintenance crane in nacelle has been developed. As a result, the maintenance cost was dramatically reduced and maintenance convenience also enhanced in offshore condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2164-2170
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• 2010

Digital Radio Frequency Memory, ( as DRFM ), is a device with the ability to restore output to the input RF signal in the required time after storing the incoming RF signals. Therefore DRFM is widely used in Jammer, EW Simulator, Target Echo Generator, and so on. This paper proposes its hardware implementation composed with the high frequency part and the digital processing part consisting of RF input/output module and local oscillator module. It is also proposed the replicated signal generation method which is consisted of the Analog-Digital conversion in the form of pulsed RF signal quantization, and FPGA to save and produce the playback signal, and RF signals to produce a Digital-Analog Conversion in the digital processing unit. This proposed scheme applied to test board and confirmed the validity of the proposed scheme through the test results obtained by the simulated input signals.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.403-415
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• 2011

In this paper, we proposed a hardware architecture to generate digital holograms at high speed. It used the modified computer-generated hologram (CGH) algorithm and adapted the pipeline-based hardware to be able to remove memory bottleneck problem. It uses not the method which generates a hologram by accumulating intermittent holograms but the one which independently generates a pixel of a final hologram and uses the appropriate CGH algorithm for the selected method. Based on the CGH algorithm we proposed the architecture of the digital hologram generator which consists of input interface part, calculating part, and normalizing part. The hardware can decrease memory usage because it repeatedly use object light sources which is stored in the internal buffer. It is also operationally parallelized by vertically adding unit cells. It can generate 86 frames of HD digital hologram per 1 second for 1K light sources.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.1-5
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• 2006

In this paper, the frequency estimator and DFT filter gain compensation for UFR(Under Frequency protection Relay) is introduced. Due to the sudden appearance of generator loads or faults in power system, the frequency is supposed to deviate from its nominal value. Because a frequency calculation is based on phase information, it needs sufficient sampling data to figure out a precious frequency. Therefore the frequency measurement for UFR needs excellent qualities such as high speed and precision with low sampling frequency Authors propose the frequency estimator which compares the vector differences and the DFT filter gain compensation which identifies DFT filter error and correct it. Using the frequency estimator and compensation, UFR which has the 0.01[ms] calculation delay and 0.003[Hz] measurement error is implemented with digital processor.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.591-597
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• 1997

Instantaneous velocity distribution within coaxial circular pipe for measurement velocity of high speed is acquired simultaneously by applying the 2-dimensional PTV system consisting of a pulse generator(AOM:Acousto-Optical Modulator), a continuous-output laser and a PC image grabber together with experimental apparatus. The basic mechanism of AOM and vector identification method and performance-related image processing techniques are discussed. Representative measuring regions $90{\times}90$mm are selected and instantaneous vectors are represented and fully developed turbulent flow of maximum velocity up to about 1.0 m/sec is obtained.

• Journal of Sensor Science and Technology
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• v.21 no.4
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• pp.303-310
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• 2012

We carried out the power performance evaluation for 1.5 MW${\times}$2 by using anemometer installed on WTGS(Wind Turbine Generator System) in the wind farm at Shi-hwa bang-a-mu-ri. In this paper, we compared and analyzed the performance of guaranteed output and measured output of WTGS which includes output curve, output coefficient, AEP(Annual Energy Product) and availability, etc.. The power performance of WTGS was optimized in the low wind speed sections(3 m/s ~ 10 m/s) and the measured output was more produced by AEP 109 % and availability 112 % than the guaranteed output. In addition, we could also cut the high cost of testing WTGS performance by using anemometer as a substitute for weather mast.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1591-1596
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• 2005

In this paper, we designed the aspheric lens by mathematical methods which are solved by refractive index. Based on these mathematical method, we manufactured the aspheric lens. Because of the usefulness of manufacturing, we used the acryl as the material. And we used a high speed machine to manufacture the aspheric lens. Also it sits in judgment the aberration of spherical distribution by using the grid fringe. Asource of laser produced by laser sheet generator passed the optical system of the aspheric lens. Though a character is to verify that the accuracy of the aspheric lens by experiment of the straight character.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.358-362
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• 1991

This paper describes enhancements made on PROSET, an, expert system which can perform setting and coordination of protective relays used in the ultra-high voltage transmission systems. Enhancements include the friendly and convenient environment for rulebase management and system manipulation, expanded setting capability, and faster processing speed which have been achieved through adoption of the new rule representation, rule order independent IE, rulebase editor, local database generator, Interface to PSS/E fault program, RB expansion etc.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.5
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• pp.37-45
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• 2003

To investigate the influence of the design and operating parameters of the headbox on hydrodynamics, a pilot headbox system and pressure monitoring apparatus were constructed. The pilot headbox system consisted of a circulating water reservoir, centrifugal pump, distributor, turbulence generator and slice. The distributor was designed to function as a pressure attenuator. Flow rate to the headbox and MD and CD velocity profiles in the slice zone were monitored using an ultrasonic flowmeter and Pitot tubes, respectively. As the distance from the step diffusor increased, evener CD velocity profile was observed. Wall effect increased with the increase of the velocity. Flow stability in the headbox was evaluated by injecting a dye at the outlet of the distributor. Application of theoretical analysis based on CFD in designing headboxes is briefly discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.105-113
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• 2011

The study about three-phase synthetic making test using DC power has been performed in order to increase the making test capacity on Vacuum Circuit Breaker. And, it made possible to solve the limitations that short-circuit testing facilities can not fulfill the testing requirements of VCB exceeding three-phase 36[kV] 31.5[kA]. By using DC power and high speed spark-gap switch, this method made the equivalence with the pre-arc that occurred during the making process under the fault condition of power system. As results, KERI(Korea Electrotechnology Research Institute) could have capacity to carry out type test for VCB under three-phase 52[kV] 40[kV], which satisfies the IEC Standard.