제주 행원 풍력 발전 시스템의 모델링 및 해석

김일환,전영진 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.1

This paper presents the modeling and analysis of wind turbine generating system(WTGS) using doubly fed induction machine as a generator. Generally, wind turbine generating system is composed of complicated machinery. So it is very difficult to present the mathematic model. This means that WTGS has a nonlinear system. Using the real output data from the WTGS for one year, it is simply possible to express the rotor and gear coupling system as a torque generator according to wind speed. Also, the modeling of electrical system can be able to present using the data sheet from the company. To analyze the proposed method, computer simulation using Psim program are presented to support the discussion.

이중여자 유도기의 가변속 풍력발전 제어해석

김일환,김정웅 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.2

In variable speed wind power generating system connected in power grid, how to capture the maximum wind energy is most important thing. Using the doubly fed induction machine as a generator in wind power generating system, it is possible to control the bidirectional slip power between grid and rotor side. This means that we can control the generating power under subsynchronous speed. To verify the theoretical analysis, computer simulation results using Psim program are presented to support the discussion.

가로수 모델에서 일부가 중첩된 장애물에 대한 해석

吳一德 大田産業大學校 1996 한밭대학교 논문집 Vol.13 No.1

Field intensity is affected by various parameters, including the frequency, distance, antenna height, atmospheric conditions, and the shape of obstacles and apertures in mobile communication. Using the Fresnel-Kirchhoff diffraction theory a formular is derived for signal intensity variation caused by rectangular obstacles and the signal intensity according to parameter variation of rectangular obstacles is numerically calculated on the basis of the theory in this paper. Assuming that a tree model consists of many different obstacles of rectangular type, 漁e signal attenuation of some overlapped by Tree model is obtained by numerical analysis with variation of the position and distance between a receiver and a transmitter, and these were compared with experimental results.

배전계통 운용을 위한 양방향성 피더모델

김일환,김세호 濟州大學校工科大學産業技術硏究所 1998 尖端技術硏究所論文集 Vol.9 No.2

This paper presents two distribution-feeder models to simplify complicated distribution system calculations. These equivalent models are developed to simulate the total series voltage drop at the end of the given feeder and the total line loss of the given feeder accurately. In addition. the proposed models are bidirectional. This means that power infeed can be at either end and the model is accurate. This feature is important for a modern distribution system in which the power infeed of the switched feeder may Change from one end to the other during service restoration or feeder reconfiguration. These bidirectional feeder models are illustrated by examples. The simulation results show that it is possible to reduce complex feeders to simple equivalent model in the study of loader-voltage profiles and losses with negligible error. even if the power infeeds of the given feeders are changed.

제주 행원 풍력발전 시스템의 역률개선에 관한 연구

김일환,김정웅,최승준 제주대학교 공과대학 첨단기술연구소 2003 尖端技術硏究所論文集 Vol.14 No.1

This paper presents a study on the power factor improvement of the Wind Turbine Generation System (WTGS) at Haeng-Won wind farm in Jeju island. Vestas WTGS named V47 as a model system is selected in this paper, and has 660 kW power ratings. In this system, the power factor correction is controlled by the conventional method with power condensor banks. Also, this system has only four bank steps, and each one capacitor bank step is cut in every one second when the generator has been cut in. This means that it is difficult to compensate the reactive power exactly. Actually, model system at Haeng-Won wind farm has very low power factor in the area of low wind speed, which is from 4 m/s to 6 m/s. This is caused by the power factor correction using power condensor bank. To improve the power factor in the area of low wind speed, we used the static var compensator (SVC) using current controlled PWM power converter by IGBT switching device. Finally, to verify the proposed method, the results of computer simulation using Psim program are presented to support the discussions.

퍼지로직에 의한 브러쉬없는 이중여자 릴럭턴스기의 계자속 제어

김일환 濟州大學校工科大學産業技術硏究所 1996 尖端技術硏究所論文集 Vol.7 No.2

This paper presents the application of fuzzy logic for field orientation control system of a Doubly Excited Brushless Reluctance Machine. Comparsion of performance obtatined with an PI controller and a fuzzy logic controller in speed loops are presented. Simulation with MATLAB permits to compare the obtained responses to a response step change and to a disturbance step change with field orientation control. A 2-hp DEBRM prototype system, with a DSP based controller is built to verify the effectiveness of proposed system. Computer simulation and labatorary experimental results are shown in excellent agreement.

SPICE에 의한 브러쉬없는 직류전동기의 전압원 인버터 구동 해석

김일환 제주대학교 1994 논문집 Vol.39 No.-

본 연구에서는 SPICE를 이용하여 역기전력이 제형파인 브러쉬없는 직류전동기를 정상상태의 120도 통 구형파 전압으로 구동할때의 해석방법을 제시하였다. SPICE로 시뮬레이션하여 전압, 전류 그리고 발생토오크를 해석하였으며 기존의 해석방법에 의한 결과와 실제실험에 의한 결과를 비교분석 하였다. 그 결과 전압, 전류, 발생토오크 특성이 서로 잘 일치하고 있음을 알 수 있다. 따라서 SPICE를 이용하면 새로운 시스템을 설계하는데 많은 소요시간과 오류를 줄일 수 있고 원하는 접속점의 파형을 쉽게 점검하는 것이 용이해질 것으로 사료된다. It is very difficult and complicated to analyze the characteristics of inverter fed driving system used by conventional computer simulation. This paper represents the method, which is easy to simulate the inverter fed motor driving system used by SPICE, which was developed as a simulation program for electronic circuits. The results of SPICE simulation are accomplished by the equivalent circuit of model motor and inverter system. The system has 3-phase voltage source inverter fed 120 conduction period using power transistor. Finally, the results of SPICE simulation are verified by comparing with the conventional computer simulation and experiment.

고성능 3상 AC/DC 전압형 PWM 컨버터 제어

김창수,김일환 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

This paper presents the control method of high performance DC power supply system. In industrial applications. diode full bridges and phase controlled rectifier systems are widely used. But these types of AC/DC controllers lead to the harmonic currents and low power factor problems. To overcome these problems, a voltage source type PWM converter using IGBT devices is proposed. Using the Park's transformation, three phase load current can be written in terms of component dq currents in a synchronously rotating reference frame. Two axis, the direct axis, d, and the quadrature axis, q, mean the active and reactive component in load current. So, it is easy to control the active and reactive component using PI control. To verify the theoretical analysis, results of computer simulation and experiments are presented to support the discussion.

풍력발전을 위한 권선형 유도발전기의 역률제어

김용현,김일환 濟州大學校 産業技術硏究所 2000 산업기술연구소논문집 Vol.11 No.2

In wind power generating system connected in power grid. the value of stator flux has almost constant because the stator side of wound rotor induction generator is connected to power grid. Using the stator and rotor current. it is possible to achieve control of generating power in stator side. This means that we can control the power factor by decoupled rotor current in synchronously rotating reference frame. To verify the theoretical analysis. results of computer simulation and experiment are presented to support the discussion.

퍼지로직을 이용한 권선형 유도기의 벡터제어

진상훈,김일환 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 Vol.11 No.2

This paper presents the concept and implementation of fuzzy logic control system for variable speed drive of wound rotor induction machine. Comparison of performance obtained with a conventional PI controller and fuzzy logic PI controller in speed control loop are presented. To verify the theoretical analysis, PWM inverter system with a DSP controller is built. Computer simulation and experimental results are shown in excellent agreement.