• Title, Summary, Keyword: synchronous generator

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Design and Characteristics Analysis of Dual Air-Gap Axial-Flux type Permanent-Magnet Synchronous Generator (2중 공극형 횡자속 영구자석 동기발전기 설계 및 특성분석)

  • Bae, Sung-Woo;Hwang, Don-Ha;Kang, Do-Hyun;Kim, Yong-Joo;Choi, Kyeong-Ho;Kim, Dong-Hee
    • Proceedings of the KIEE Conference
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    • pp.1063-1066
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    • 2003
  • This paper presents the design and characteristics analysis of axial-flux permanent-magnet (PM) synchronous generator of two air-gap. Dual axial-flux type PM synchronous generator commonly appears in applications where the generator axial dimension is more limited than the radial dimension. The strengths of dual axial-flux generator include ; (1) by employing two air-gaps, the rotor-stator attractive forces are balanced and no net axial or thrust load appeals on the generator hearings ; (2) heat produced by the stator windings appears on the outside of the generator, making it relatively easy to remove, and so on. In this paper, the simple magnetic equivalent circuit approach is used for initial design iteration, and the finite-element method is applied to analyze the detailed characteristics. The test results of driving characteristics are presented as well. The results are very similar to predicted performance of design.

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Analysis on Air-Gap Magnetic Flux of Synchronous Generator According to Short-Circuit Types in Winding (권선단락 유형별 동기발전기의 공극자속 파형 분석)

  • Bae, Duck-Kweon;Kim, Dong-Hun;Park, Jung-Shin;Lee, Dong-Young;Lee, Sung-Ill
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.5
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    • pp.929-935
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    • 2009
  • As modem industrialized society progresses, the demand for electric power is increasing rapidly. The electric power system is getting amazingly bigger and complicated, which can easily induce serious troubles from the potential of large fault problems and/or system failure. The monitoring and diagnosis of the electric machine for the fault detection and protection has been important part in the electric power system. Most faults in the generator appear in the winding. This paper presents the air-gap magnetic flux characteristic of a small-scale 2-pole synchronous generator according to the faults in the field winding to protect the generator from the fault. The magnetic flux patterns in air-gap of a generator under various fault conditions as well as a normal state are simulated by using finite element method. These results are successfully applied to the detection and diagnosis of the short-circuit condition in rotor windings of a high capacitor generator.

Operating Characteristic Analysis of the Induction Generator by the Reactor Starting (리액터 기동 유도발전기의 동작 특성 해석)

  • Kim, Jong-Gyeum
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.3
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    • pp.138-142
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    • 2014
  • In general, the voltage stability of induction generator is lower than synchronous generator. However, induction generator has many advantages rather than a synchronous generator in terms of price and maintenance. So Induction generator is used little by little in small hydroelectric power station rather than 1000kW recently. Squirrel cage induction generator generates a high inrush current at the grid-connection. This high inrush current causes a voltage drop on the grid. In order to increase the penetration of the induction generator, it is necessary to present a method of reducing inrush current. In this study, we suggested that it is possible to present a reactor startup method, by applying the parameter to reduce the voltage drop.

Soft Start-up Characteristics Analysis of Squirrel Cage Induction Generator (농형 유도 발전기의 소프트 기동 특성 해석)

  • Kim, Jong-Gyeum;Park, Young-Jeen
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.1
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    • pp.103-107
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    • 2016
  • In general, the voltage stability of induction generator is lower than synchronous generator. Induction generator has a number of advantages over the synchronous generator on the side of price and maintenance. So Induction generator has been applied to the small hydroelectric power of low output. Induction generator usually generates a high current during grid connection. The high current that occurs during grid connection can cause a voltage drop in the system. In order to increase the supply of the induction generator, it is necessary to propose a method of reducing high current. This paper proposes some method of the soft start to reduce voltage drop caused by the large starting current. soft-start method has high voltage drop effect than direct start method, control of firing angle can be increased the voltage drop effect.

A Development of Real-time Monitoring Techniques for Synchronous Electric Generator Systems (동기 발전기 시스템의 실시간 모니터링 기술 개발)

  • Cho, Hyun Cheol
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.4
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    • pp.182-187
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    • 2017
  • Synchronous generators have been significantly applied in large-scale power plants and its monitoring systems are additionally established to sequentially observe states and outputs. We develop a computer based monitoring device for three-phase synchronous power generators in this paper. First, a test-bed of such generator system is created and then a interface board is constructed to transfer electric signals including the output voltage and the current from generators into a computer system via a data acquisition device. Its RMS(root-mean-square) values are continuously shown on a screen of computer systems and its time-histories graphs are additionally illustrated under a graphic user interface(GUI) mode. Lastly, we carry out real-time experiments using the generator system with the monitoring device to demonstrate its reliability and superiority by comparing results of a generic power analyzer which is well-used in measuring various power systems practically.

Design of Control System for 1kW Grid-connected Permanent Magnet Synchronous Generator (가스 엔진용 1kW급 계통 연계 영구자석형 동기발전기 구동 시스템 설계)

  • Lee, Taeyeong;Cho, Younghoon
    • Proceedings of the KIPE Conference
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    • pp.69-70
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    • 2017
  • This paper presents design of control system for permanent magnet synchronous generator(PMSG). The gas engine make rotating mechanical energy from gas fuel energy. The rotor of synchronous generator is connected to axis of engine. And it converts the mechanical energy to the electrical energy. The control system of PMSG helps the electrical energy to flow to grid. the single phase pfc rectifier controls the DC-link voltage by controlling the current of filter inductor. If the DC-link voltage is higher than the voltage reference, the filter current could be controlled to flow to grid. The three phase inverter controls the stator current of generator. The direction of the current is controlled depends on motoring or generating mode. The feasibility of the grid-connected PMSG is verified by the experimental results with 1kW prototype.

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Performance of Double Fed Induction Machine at Sub- and Super-Synchronous Speed in Wind Energy Conversion System

  • Eskander, Mona N.;Saleh, Mahmoud A.;El-Hagry, Mohsen M.T.
    • Journal of Power Electronics
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    • v.9 no.4
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    • pp.575-581
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    • 2009
  • In this paper two modes of operating a wound rotor induction machine as a generator at sub-and super-synchronous speeds in wind energy conversion systems are investigated. In the first mode, known as double fed induction generator (DFIG), the rotor circuit is fed from the ac mains via a controlled rectifier and a forced commutated inverter. Adjusting the applied rotor voltage magnitude and phase leads to machine operation as a generator at sub-synchronous speeds. In the second mode, the machine is operated in a slip recovery scheme where the slip energy is fed back to the ac mains via a rectifier and line commutated inverter. This mode is described as double output induction generator (DOIG) leading to increase the efficiency of the wind-to electrical energy conversion system. Simulated results of both modes are presented. Experimental verification of the simulated results are presented for the DOIG mode of operation, showing larger amount of power captured and better power factor when compared to conventional induction generators.

Status of 3 MW PM Synchronous Generator Development Project for Off-shore WECS (3MW 해상풍력용 영구자석 동기발전기 개발현황)

  • Kim, Dong-Eon;Han, Hong-Sik;Lee, Hong-Gi;Jung, Yung-Gyu;Suh, Hyung-Suck;Chung, Chin-Wha
    • 한국신재생에너지학회:학술대회논문집
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    • pp.423-426
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    • 2007
  • Pohang Wind Energy Research Center (PoWER-C) is developing a 3 MW Radial Flux Permanent Magnet (RFPM) Synchronous Generator for offshore Wind Energy Converter (WEC). The rotor rpm is 15.7 and the gear ratio is set to be 92.93. The nominal generator rpm at the rated load is about 1459. To reduce the switching loss in the power electronics, the maximum frequency is limited to 100 Hz. This requirement limits the number of pole to six or eight. Permanent magnet excitation is assumed for higher energy yield and higher efficiency. In this report, the requirements and the first efforts for the physics design are described.

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A Coupled Circuit and Field Analysis of a Stand-Alone Permanent-Magnet Synchronous Generator with Inset Rotor

  • Chan T. F.;Yan Lie-Tong;Lai L. L.
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.3
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    • pp.253-257
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    • 2005
  • By using a coupled circuit, time-stepping, two-dimensional finite element method (2-D FEM), the performance of a stand-alone permanent-magnet synchronous generator (PMSG) with inset rotor can be computed without involving the classical two-axis model. The effects of interpolar air gap length and armature resistance on the load characteristics are investigated. It is shown that the interpolar flux density, and hence the amount of voltage compensation, is affected by magnetic saturation. Validity of the coupled circuit and field analysis is confirmed by experiments on a prototype generator. The machine exhibits an approximately level load characteristic when it is supplying an isolated unity-power-factor load.

Analytical Approach for Rotor Loss Prediction of Permanent Magnet Synchronous Generator with Multi-Pole Rotor (다극 회전자를 갖는 영구자석 동기 발전기의 회전자 손실 예측을 위한 해석적 접근)

  • Jang, Seok-Myeong;Kim, Hyun-Kyu;Choi, Jang-Young;Ko, Kyoung-Jin;Sung, Tae-Hyun;Kim, Il-Jung
    • Proceedings of the KIEE Conference
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    • pp.719-720
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    • 2008
  • This paper deals with analytical approach for rotor loss prediction of permanent magnet synchronous generator(PMSG). The rotor losses of synchronous generator are induced by the magnets. Since stator of our model is skewed, slotting effect can be negligible for our PM wind turbine generator. In order to calculate eddy current, this paper derives analytical solutions by the magnetic vector potential. Finally this paper compared analytical result with eddy current density obtained from finite element(FE) calculations using phase current harmonics analysis.

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