• Title, Summary, Keyword: synchronous generator

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Study on the Capacitor-self-excited Three-phase Synchronous Generator (A 캐패시터 자력식 삼상동기발전기에 관한 연구)

  • 정연택;김영동
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.33 no.11
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    • pp.425-432
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    • 1984
  • This paper is to propse a new self-excitation method of synchronous generator. Instead of conventional exciter of synchronous generator, the additional winding which is arranged in addition to the armature winding, is used in this generator. The output terminal of the additional winding is connected to a capacitor and to a full wave rectifier in series. In this configuration, one source double excitation which is composed of capacitor-self-excitation by lead urrent and direct current excitation by rectifier, is induced. The result is that` The excetation efficency is improved greatly and output waveform is improved also. In three-phase synchronous generator using the new method of the one source double excitation, voltage element (shunt characteristics) and current element (series characteristics)are compounded in scalar by adapting star-point-open-rectifier system. The result is as following` The effect of load power factor angle on voltage regulation is reduced greatly, compound characteristics is become manifold by controlling capacity of capacitor, and transient response is improved.

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Voltage Control of Synchronous Generator for Ship Using a PMG Type Digital AVR (PMG Type 디지털 AVR을 이용한 선박용 동기발전기 출력전압제어)

  • Yu, Dong-Hwan;Park, Sang-Hoon;Yu, Jae-Sung;Lee, Sang-Suk;Kim, Young-Real;Won, Chung-Yuen
    • Proceedings of the KIPE Conference
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    • pp.136-138
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    • 2008
  • The output voltage of synchronous generator is regulated constantly by field current control in excitation system. Most of ship generator exciter system uses the thyristor phase controlled rectifier. However this rectifier is difficult to realize that the speed control system because its control period is slower than MOSFET and IGBT type converter. Therefore, this paper deals with PMG(Permanent Magnet Generator) type digital excitation system using MOSFET for ship synchronous generator. The organization of this excitation system is very simple. When the generator is under the short circuit accident, the output voltage becomes zero state and AVR can not operate. Thus generator requires the function for flowing output current through CBS. The performance of the proposed system is evaluated on a 10kVA experimental prototype circuit in place of real ship generator.

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Development of Inter-Turn Short Circuits Sensor for Field Winding of Synchronous Generator

  • Nam J-H;Jeon Y-S;Choe G-H;Lee S-H;Jeong S-Y;Yoo B-Y;Ju Y-H;Lee Y-J;Shin W-S
    • Proceedings of the KIPE Conference
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    • pp.56-59
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    • 2001
  • An effective method of detecting inter-turn short circuits on round rotor windings is described. Shorted-turns can have significant effects on a generator and its performance. A method of detecting inter-turn short circuits on rotor windings is described. The approach used is to measure the rate of change of the air-gap flux density wave when the rotor is at operating speed and excitation is applied to the field winding. The inter-turn short circuits sensor for synchronous generator's field winding has been developed. The sensor, installed in the generator air-gap, senses the slot leakage flux of field winding and produces a voltage waveform proportional to the rate of change of the flux. For identification of reliability for sensor, a inter-turn short circuits test was performed at the West-Inchon combined cycle power plant on gas turbine generator and steam turbine generator. This sensor will be used as a detecting of shorted-turn for field winding of synchronous generator. The purpose of this paper is to describe the design and operation of a sensitive inter-turn short circuits detector. In this paper, development of inter-turn short circuits sensor for field winding of synchronous generator and application in a field.

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Great capacity Generator of Wind Turbine (대용량 출력 풍력발전기 설계)

  • Hur, Man-Cheol
    • 한국신재생에너지학회:학술대회논문집
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    • pp.366-368
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    • 2007
  • Mr. Hur has developed the 7500KW permanent magnet synchronous generator. The 7500KW generator has dual blade system with vertical axis type generation module. The 7500KW generator will generating that it is too expensive and construction payment. The advantages of dual blade system are cheap in generation with better efficiency, and safety compact structure. But also this system has the expensive slide ring for to distribute electrical power.

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Sub-Synchronous Range of Operation for a Wind Driven Double-Fed Induction Generator

  • Saleh, Mahmoud Abdel Halim;Eskander, Mona Naguib
    • Journal of Power Electronics
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    • v.10 no.1
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    • pp.72-78
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    • 2010
  • In this paper the operation of a double-fed wound-rotor induction machine, coupled to a wind turbine, as a generator at sub-synchronous speeds is investigated. A novel approach is used in the analysis, namely, the rotor power flow approach. The conditions necessary for operating the machine as a double-fed induction generator (DFIG) are deduced. Formulae describing the factors affecting the range of sub-synchronous speeds within which generation occurs are deduced. The variations in the magnitude and phase angle of the voltage injected to the rotor circuit as the speed of the machine changes to achieve generation at the widest possible sub-synchronous speed range is presented. Also, the effect of the rotor parameters on the generation range is presented. The analysis proved that the generation range could increase from sub-synchronous to super-synchronous speeds, which increases the amount of energy captured by the wind energy conversion system (WECS) as result of utilizing the power available in the wind at low wind speeds.

A Study on Excitation System for Synchronous Generator using Current Mode Controlled PWM Converter (전류제어형 PWM컨버터를 이용한 동기발전기용 여자시스템에 관한 연구)

  • 장수진;류동균;서민성;김준호;원충연;이진국
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.3
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    • pp.32-39
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    • 2003
  • The output voltage of synchronous generator is regulated constantly by field current control in excitation system High frequency PWM converter (current control mode buck converter) type excitation systam fer synchronous generator is able to control exciter current when the load change happened. This paper deals with the design and evaluation of the excitation system for a synchronous generator to improve the steady state and transient stability. The simulation and experimental results show that the proposed excitation system is able to improve the response time by the DVR(digital voltage regulator) of 50[kW] synchronous generator.

The Current Boost Type Static Excitation Systems for Synchronous Generator (전류 부스터 정류기를 갖는 정지형 여자시스템 특성 개선 연구)

  • 임익헌;김장목;김경철
    • Proceedings of the KIPE Conference
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    • pp.193-196
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    • 1999
  • The current boost type atatic excitation system for synchronous generator that can sustain prope output voltage level even at fault condition is proposed. The proposed excitation system is capabl of supplying level 60% of the rated voltage. The proposed system is verified and tested using computer simulations as well as load tests. The load tests are performed with a 5KVA synchronous generator driven by a ac motor. The actual tests results indicated a good performance.

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Synchronous Generator Protection using Fault Currents (고장전류를 이용한 동기 발전기 보호)

  • Park, Cheol-Won;An, Jun-Yeong;Lee, Sang-Seong;Sin, Myeong-Cheol
    • Proceedings of the KIEE Conference
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    • pp.399-401
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    • 2006
  • This paper proposes a synchronous generator protection algorithm using Discrete Wavelet Transform for detection of fault currents. The proposed technique is implemented by using the C language and the Wavemenu of MATLAB Toolbox, and consists of normal state and internal fault state. The effectiveness of proposed method is demonstrated by MATLAB simulation package for synchronous generator, which collects the balanced and unbalanced fault currents through simulation.

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Experimental Study on Frequency Support of Variable Speed Wind Turbine Based on Electromagnetic Coupler

  • You, Rui;Chai, Jianyun;Sun, Xudong;Bi, Daqiang;Wu, Xinzhen
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.195-203
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    • 2018
  • In the variable speed Wind Turbine based on ElectroMagnetic Coupler (WT-EMC), a synchronous generator is coupled directly to the grid. Therefore, like conventional power plants, WT-EMC is able to inherently support grid frequency. However, due to the reduced inertia of the synchronous generator, WT-EMC is expected to be controlled to increase its output power in response to a grid frequency drop to support grid frequency. Similar to the grid frequency support control of Type 3 or Type 4 wind turbine, inertial control and droop control can be used to calculate the WT-EMC additional output power reference according to the synchronous generator speed. In this paper, an experimental platform is built to study the grid frequency support from WT-EMC with inertial control and droop control. Two synchronous generators, driven by two induction motors controlled by two converters, are used to emulate the synchronous generators in conventional power plants and in WT-EMCs respectively. The effectiveness of the grid frequency support from WT-EMC with inertial control and droop control responding to a grid frequency drop is validated by experimental results. The selection of the grid frequency support controller and its gain for WT-EMC is analyzed briefly.

Optimal Design of a Direct-Drive Permanent Magnet Synchronous Generator for Small-Scale Wind Energy Conversion Systems

  • Abbasian, Mohammadali;Isfahani, Arash Hassanpour
    • Journal of Magnetics
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    • v.16 no.4
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    • pp.379-385
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    • 2011
  • This paper presents an optimal design of a direct-drive permanent magnet synchronous generator for a small-scale wind energy conversion system. An analytical model of a small-scale grid-connected wind energy conversion system is presented, and the effects of generator design parameters on the payback period of the system are investigated. An optimization procedure based on genetic algorithm method is then employed to optimize four design parameters of the generator for use in a region with relatively low wind-speed. The aim of optimization is minimizing the payback period of the initial investment on wind energy conversion systems for residential applications. This makes the use of these systems more economical and appealing. Finite element method is employed to evaluate the performance of the optimized generator. The results obtained from finite element analysis are close to those achieved by analytical model.