• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.142-149
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• 2004

This paper presents a neural network controller of a grid-connected wind energy conversion system for extracting maximum power from wind and a power controller to transfer the maximum power extracted into a utility grid. It discusses the modeling and simulation of the wind energy conversion system with the controllers, which consists of an induction generator, a transformer, a link of a rectifier, and an inverter. The paper describes tile drive train model, induction generator model and grid-interface model for dynamics analysis. Maximum power extraction is achieved by controlling the pitch angle of the rotor blades by a neural network controller. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation. The simulation results performed on MATLAB show the variation of the generator torque, the generator rotor speed, the pitch angle, and real/reactive power injected into the grid, etc. Based on the simulation results, the effectiveness of the proposed controllers is verified.

• The Journal of the Acoustical Society of Korea
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• v.17 no.1
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• pp.80-85
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• 1998

본 논문에서는 음성합성기에서 합성음의 자연성을 향상시키기 위한 한 방법으로 운 율 제어요소중 세기 제어 모델을 통계적인 방법을 이용하여 제안하였다. 세기 제어 모델을 구성하기 위하여, 음성의 세기는 피치에 비례한다는 사실에 기반하여, 녹음된 음성 데이터에 서 음절의 각 모음에 대한 평균파워와 평균피치를 구하고, 피치를 종속변수로 하는 모음의 세기 예측식을 만들었다. 예측식에 의하여 얻어진 세기값과 실제 측정된 세기값과의 상관도 는 전체모음에 대하여 약 0.63으로 나타났다. 본 논문에서는 예측 세기와 실제 세기와의 상 관도를 향상시키기 위하여 피치만을 고려하여 예측된 세기값을 음운환경을 고려하여 선형 오차를 보정하는 방법을 제안하였고, 이 방법을 이용하여 얻어진 세기값은 전체모음에 대하 여 실제 세기값과 0.71의 상관도로 향상시킬 수 있었다.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.29-36
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• 2024

Recently, the concept of Urban Air Mobility (UAM) has expanded to Advanced Air Mobility (AAM). A tilt rotor type of vertical take-off and landing aircraft has been actively studied and developed. A tilt-rotor aircraft can perform a transition flight between vertical and horizontal flights. A blade pitch angle control system can be used for flight stability during transition flight time. In addition, Individual Blade Control (IBC) can reduce noise and vibration generated in transition flight. This paper proposed Disturbance Observer Based Control (DOBC) and Time Delay Control (TDC) for individual blade control of an Electro-Mechanical Actuator (EMA) based blade pitch angle control system. To compare and analyze proposed controllers, numerical simulations were conducted with DOBC and TDC.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.40.1-40.1
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• 2011

This paper presents a pitch controller which can hold output power constant at the rated value. Although wind turbine contains complicated nonlinearities, its behaviour within a certain operating range of a point can be approximated by that of a linear model. By doing so, we can apply rather simple and systematic linear control techniques such as PID and LQR(Linear Quadratic Regulator) to design a linear pitch controller. Because these linear controllers are valid only in a sufficiently small range around an operating point, linearized wind turbine model under the condition of varying wind speed needs a linear pitch controller can achieve the aims of tracking the rated rotor rotational speed. We propose an improved linear pitch controller taking each merit of LQR and PI controller under the condition of varying operating points in this paper.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1065-1071
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• 2012

Wind energy is becoming one of the most preferable alternatives to conventional sources of electric power that rely on fossil fuels. For stable electric power generation, constant rotating speed control of a wind turbine is performed through pitch control and stall control of the turbine blades. Recently, variable pitch control has been implemented in modern wind turbines to harvest more energy at variable wind speeds that are even lower than the rated one. Although wind turbine pitch controllers are currently optimized using a step response via the Ziegler-Nichols auto-tuning process, this approach does not satisfy the requirements of variable pitch control. In this study, the variable pitch controller was optimized by a genetic algorithm using a neural network model that was constructed by the Latin Hypercube sampling method to improve the Ziegler-Nichols auto-tuning process. The optimized solution shows that the root mean square error, rise time, and settle time are respectively improved by more than 7.64%, 15.8%, and 15.3% compared with the corresponding initial solutions obtained by the Ziegler-Nichols auto-tuning process.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.59-64
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• 2015

The pitch control system in wind turbines becomes more and more important as the wind turbines are larger in multi-MW size. PI controller has been applied in most pitch controllers and it has been known that gain-scheduling is essential for pitch control of wind turbines. A demo model of 2 MW wind turbine which represents the whole dynamics of wind turbine including dynamic behaviors of blade, tower and rotational shaft is given in the commercial Bladed S/W for real wind turbines. In this paper, some results on step responses of the pitch PI controller and effectiveness of gain-scheduled pitch PI controller are presented through the Bladed S/W for the 2 MW wind turbine.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.537-538
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• 2015

최근 자전거의 활용범위가 출퇴근뿐만 아니라, 친환경 헬스케어 부각으로 자전거 타는 것에 많이 이용되고 있는 실정이다. 근래 몇 년 사이에 정부에서도 자전거 전용도로를 도시외각뿐만 아니라 자전거로 출퇴근 이용자들을 위해 안전하게 운행할 수 있도록 자전거 전용도로를 전국에 확대설치 하여 자전거 보급을 확대 하고 있다. 하지만 현재 국내에 많이 보급되어 있는 자전거는 대부분이 외국에서 반제품이 수입되어 국내에서 완제품으로 조림하여 판매되는 제품들이 주를 이루고 있으며, 자전거 부품 중에도 최근 외국에서 개발이 진행되고 있는 전자변속기 또한 외국의 기술들이 도입되어 제품들이 출시되고 있는 실정이다. 이에 외국의 기술적 우위로 인하여 한국의 자전거 산업발전에 어려움이 많은 것이 현실이다. 본 연구에서는 리니어모터를 이용하여 디지털 전동 변속기를 개발 하여, 변속의 신속성, 정확성을 확보하면서, 동시에 외국의 기술적 장벽을 넘고자 한다. 현행 자전거 뒤 변속기의 정확한 변위위치 확보하기 위하여 자전거 핸들에 장착되어 있는 변속레버를 디지털화 하여, 변속을 제어하게 되면 뒤쪽에 설치되어 있는 리니어모터를 위치 제어함으로써 가이드 샤프트 피치에 의하여 변속위치가 정밀하게 제어 할 수 있는 전동 변속기 제어시스템을 제안하고자 한다.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.2
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• pp.159-163
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• 2008

In this paper, a simplified type of adaptive controller using Nussbaum gain for the control of the spacecrapt with elastic appendages is suggested. This method doesn't need the information of the high frequency components in transfer function. While the pitch angle tracks the desired value by this method, the elastic modes are also stabilized. Only pitch angle and the pitch rate are used for the design of the output feedback controller. Especially all system parameters and the high frequency gain are assumed to be unknown. For design simplicity, a controller is designed by using only the linear part, and it's shown to satisfy the nonlinear system by the simulation with basic explanations. By using the Lyapunov function, the stability of the suggested algorithm is demonstrated, and also the effectiveness of the suggested algorithm is verified by showing the computer simulation results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1059-1065
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• 2014

Wind turbine system can obtain the maximum wind energy using torque control under the rated wind speed, and wind turbine power is controlled as the rated power using pitch control over the rated wind speed. In this paper, we present a method for wind turbine pitch controller using neural networks. The purpose of the pitch control is to control generator speed and power in the above rated wind speed. To improve the neural network pitch controller, the difference between a rated and current speed of generator has been used for another input of neural networks as well as wind speed. Error back-propagation algorithm is used for training the neural network pitch controller and simulation and Matlab/Simulink is used for verifying that this system is controlled well.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.127-132
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• 2017

In this paper, we propose a controller gain based on model based design and implement the two-wheel inverted pendulum type robot using NXT Lego and RobotC language. Two-wheel inverted pendulum robot consists of NXT mindstorm, servo DC motor with encoder, gyro sensor, and accelerometer sensor. We measurement wheel angle using bulit-in encoder and calculate wheel angle speed using moving average method. Gyro measures body angular velocity and accelerometer measures body pitch angle. We calculate body angle with complementary filter using gyro and accelerometer sensor. The control gain is a weighted value for wheel angle, wheel angular velocity, body pitch angle, and body pich angular velocity, respectively. We experiment and observe the effect of two-wheel inverted pendulum with respect to change of control gains.