• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.128-129
• /
• 2012

This paper proposed the wind turbine simulator for comparative study of the MPPT controls. The development of this wind turbine simulator is based on the torque controlled induction motor. The torque reference is obtained from a mathematical model of wind turbine whereas the inputs are rotor speed, wind speed and fixed-value of pitch angle. By using this wind turbine simulator, the real wind is not needed. Wind speed information can be stored and regenerated anytime. Hence it is possible to apply the same wind speed condition to different MPPT controls. With the same wind speed condition, it can fairly compare the advantages and disadvantages of the MPPT controls. The proposed wind turbine simulator is verified through PSIM simulation.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.2000-2001
• /
• 2007

Wind power generation system based on the PSCAD/EMTD is proposed in this paper for the simulations under the real weather conditions. Real field data of weather condition is interfaced to PSCAD/EMTDC using Fortran program interfaced method. And a new turbine component is developed using characteristic equation of a wind turbine and pitch angle control algorism. The generator output and current supplied into utility can be obtained by the transient analysis using PSCAD/EMTDC.

• Proceedings of the KIEE Conference
• /
• 2004.11b
• /
• pp.17-20
• /
• 2004

This paper presents a modeling and simulation of a grid-connected wind turbine generation system with respect to wind variations and three-phase fault in the system. It describes the modeling of the wind turbine system including the drive train model, induction generator model, and grid-interface model on MATLAB/Simulink. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction for wind speed variations and the duration of a fault on the system influences on the output of the wind turbine generator.

• Transactions of Materials Processing
• /
• v.19 no.2
• /
• pp.127-131
• /
• 2010

Carbon-epoxy prepreg has been introduced in the forming of the upper and lower swash plates that control the pitch of rotor blade of unmanned helicopter because of its lightweight. Taguchi experimental method has been used by introducing the variables such as arrangement angle, laminated number and forming temperature, in order to obtain the proper forming method by using prepreg satisfying the required strength of the swash plate. In the evaluation of structural safety for the swash plates, three kinds of models are considered by using FE-analysis. In comparison of the hot forged products with Al6061-T6 and the formed products with prepreg, it was found that ultimate tensile strength of the products with prepreg is three times higher than that of the Al6061-T6, and the weight reduction of 68.5g can be achieved by using prepreg swash plates.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.261-264
• /
• 2006

In this paper, doubly-fed induction-type wind power generation system simulation model for grid connection is developed. The simulation model is based on PSCAD/EMTDC and consists of rotor-blade, blade controller, generator power converter and generator controller Blade controller controls the blade pitch angle for starting, peak power limiting and emergency condition. Generator controller controls the generator output power to maximize the system efficiency. Simulation results are shown for the variable wind speed conditions. The simulation model can be utilized for study of actual interaction between wind turbine and grid for reliable operation and protection of power system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.11 no.5
• /
• pp.700-708
• /
• 1999

The optimum dimple shape and arrangement in the channel of a plate heat exchanger with staggered dimples are proposed in this study. Four important geometric parameters are selected as design variables, the pressure drop and heat transfer characteristics are examined in the channel of plate heat exchangers. The optimization is accomplished by minimizing the global criterion function which consists of the correlations of Nusselt number and pressure drop. The optimum geometric parameters were found at the dimensionless dimple distance (L) of 0.272, the dimensionless dimple angle ($\beta$) of 0.44, the dimensionless dimple volume (V) of 0.106 and the dimensionless dimple pitch (G) of 0.195. It is found that the heat transfer and pressure drop of the optimum model are increased by approximately 227.9% and 32.9%, respectively, compared to those of the base model.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.7
• /
• pp.19-25
• /
• 1995

Presently, along with the advance of high-technology, the precise measurement of linear displacement has become a staple requirement, and consequently the high resolution with submicron order has also been required in precise positioning and carriaging. In this paper, we advance a propose on a new type of laser encoder based on the principle of phase analysis of the moire fringes from superimposed two gratings. The phase angle as an information of displacement can be accurately calculated by detecting the change in brighness at four points of the fringes. The actual application of four point method to the moire fringes is performed thru microcomputer for general purpose, and the measuring procedure is also studied in this research. As an experimental result, in the case of using 20 .mu. m-pitch gratings, it is validated that this method has the resolution of 0.01 .mu. m and the accuracy of .+-. 0.15 .mu. m over the setting range of 100mm.

• Journal of the Korean Solar Energy Society
• /
• v.37 no.1
• /
• pp.1-14
• /
• 2017

A series of coupled time domain simulations considering stochastic waves and wind based on five 1-h time-domain analyses are performed in normal operating conditions. Power performance and tower base Fore-Aft bending moment and pitching motion response of the floating spar-buoy wind turbine with 2 MW direct-drive PMSG have been analyzed by using HAWC2 that account for aero-hydro-servo-elastic time domain simulations. When the floating spar-buoy wind turbine is tilted in the wind direction, maximum of platform pitching motion is close to $4^{\circ}$. Statistical characteristics of tower base Fore-Aft bending moment of floating spar-buoy wind turbine are compared to that of land-based wind turbine. Maximum of tower base Fore-Aft bending moment of floating spar-buoy wind turbine and land-based wind is 94,448 kNm, 40,560 kNm respectively. This results is due to changes in blade pitch angle resulting from relative motion between wave and movement of the floating spar-buoy wind turbine.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.6
• /
• pp.489-495
• /
• 2007

An experimental study was carried out in order to measure the pitch dynamic stability derivatives of a standard dynamics model in a low-speed wind tunnel. When a trigger signal is generated, the aircraft model starts oscillation with constant amplitudes and frequencies provided by DC electrical servomotor. The measured data are simultaneously recorded on a data recorder for 25 cycles of the model oscillation. The Phase shift needed to compute the dynamic stability derivatives is determined by calculating differences between the peak values of the input and output signals from the dynamic stability balance. Stabilator effects on the stability derivatives were also investigated with deflection angles. Although the driving apparatus and experimental equipments manufactured creatively for this study are different from other experiments, the variational trend of dynamic stability derivatives with the angle of attack is in a good accordance with the results of TPI, NAE, and FFA.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.1
• /
• pp.12-21
• /
• 2010

This paper focuses on the hover performance experiment of a small-scale single rotor in partial ground conditions. In this study, small-scale rotor blade rotating device and floor panel are used to include partial ground effect. Thrust and torque were measured with varying collective pitch angles at fixed rotor rotating speed. The overlap distance between rotor and ground is d, the rotor diameter is D. It was shown that the ground effects have little effect on the rotor performance until d/D is 0.25. Four blade rotor has more increased thrust and more reduced power than those of two blade rotor because of stronger ground effect. In addition, it was also found that the thrust increases as a collective pitch angle become smaller. Based on these experiment results, we deduced new empirical equation considered blade number and partial ground effect.