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 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.

풍력발전을 위한 권선형 유도발전기의 역률제어

김용현,김일환 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 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.

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.

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.

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.

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.

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.

풍력발전을 위한 회전변환기가 없는 이중 여자 유도기의 전력제어

김용현,김일환 제주대학교 산업기술연구소 1999 尖端技術硏究所論文集 Vol.10 No.2

This paper describes power control of a doubly fed induction machine(DFIM) for wind energy generation without rotational transducers. A stator flux orientation scheme and rotor speed estimator are employed to achieve control of generating power in stator side. To verify the theoretical analysis, a 5-hp DFIM prototype system and PWM power converter are built. Results of computer simulation and experiment are presented to support the discussion.

고저항 지대에서의 코어링 접지공사에 관한 연구

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

The resistivity of the soil depends on many parameters. It depends on the type of soil and therefore varies with distance as well as with depth. Especially soil resistivity of volcanic area is very high and it is difficult to acquire necessary grounding resistivity. This paper introduces the efficient grounding construction using coring technique for proper grounding resistance in high resistivity area. Because it is difficult to measure the accurate resistivity of soils, their resistivities are estimated using measured value of ground resistance and equivalent radius calculation method. Estimated resistivities are used for grounding resistance in scheduled grounding region.