• Title/Summary/Keyword: Magnetizing system

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Computer Modeling and Temperature Estimation method of Capacitor Discharge Impulse magnetizer-Magnetizing Fixture System

  • 김필수;김용;백수현;권순도;윤석호
    • The Transactions of the Korean Institute of Power Electronics
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    • v.2 no.2
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    • pp.1-7
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    • 1997
  • 커패시터 방전회로의 제작 및 시험을 위해서는 고가의 비용과 위험요소가 내재되어 있으며 특히 고전력 응용을 위해서는 이러한 요소는 더욱 커지게 된다. 그 대체방법으로는 컴퓨터를 이용하여 이 회로의 동작을 모델링하고 시뮬레이션하는 것이다. 본 연구에서는 커패시터 방전 임펄스 착자가 착아 요크 시스템을 위한 SPICE 모델을 개발하고 시뮬레이션 결과를 실제 시스템의 측정치와 비교하였다. 또한 착자기 시스템의 방전회로를 위한 온도산정방법을 제안하였다. 특히 임펄스 착자기의 방전회로의 온도산정은 착자회로 설계의 중요한 지침이 되므로 극히 중요하다. 본 연구에 이용된 착자기는 저손실 유입 커패시터이며, 최대 1200[V]의 충전이 가능하다. 이러한 착자 모델의 개발을 통하여 고임펄스 방전 회로의 설계 및 개발에 소요되는 시간 및 비용을 절약하는데 크게 기여할 것이다.

A Circuit of Capacitor-Discharge Impulse Magnetizer and Magnetizing Characteristics of Ferrite Magnet (커패시터 방전 임펄스 착자기 회로와 페라이트 자석의 착자특성)

  • Baek, Su-Hyeon;Yun, Su-Bong;Kim, Pil-Su
    • Proceedings of the KIEE Conference
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    • 1992.07b
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    • pp.645-648
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    • 1992
  • In a capacitor-discharge impulse magnetizer, one of the magnetic application system, a magnet is magnetized by the discharging current of capacitors. The conventional design of the magnetizer has been based on many year's experience. The behaviour of flux in the magnetizer should be calculated in order to produce the desired magnets. The analysis of the flux distribution is quite difficult. This is because both the magnetizing current and the applied voltage to the magnetizer are unknown. This paper describes the development of computer model for a capacitor-discharge impulse magnetizer using SPICE. Also, the detailed distribution of the flux density in a magnet magnetized by the impulse magnetizer be analyed.

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CT compensating algorithm Based on a Digital Signal Processor (DSP를 이용한 변류기 보상 알고리즘)

  • Kang, Yong-Cheol;Lee, Byung-Eun;So, Soon-Hong;Hwang, Tae-Keun;Lee, Ji-Hoon;Cha, Sun-Hee;Kim, Yeon-Hee;Jang, Sung-Il
    • Proceedings of the KIEE Conference
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    • 2005.11b
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    • pp.255-257
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    • 2005
  • This paper proposes a compensating algorithm of a measurement torrent transformer (CT) using DSP. The core flux is calculated and then magnetizing current is estimated in accordance with the flux-magnetizing current curve. The core loss current is obtained with the core loss resistance and the secondary voltage. The correct secondary current is estimated by adding the exciting current to the measured secondary current. The performance of the proposed algorithm was tested using EMTP generated data. The experiment on the real CT was conducted using the prototype compensated system based on a digital signal processor. The results indicate that the algorithm can increase the accuracy of the measurement CT significantly.

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Modeling and Control of Three-Phase Self-Excited Induction Generator Connected to Grid

  • Chandrasekaran, Natarajan;Karthikeyan, A
    • Transactions on Electrical and Electronic Materials
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    • v.18 no.5
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    • pp.265-272
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    • 2017
  • This paper presents the dynamic modeling, analysis, and control of an AC/DC/AC-assisted, self-excited induction generator connected to the grid. The dynamic model includes wind turbine models with pitch control, gear boxes, self-excited induction generators, excitation capacitance, inductive load models, controlled six-pulse rectifiers, and novel state-space models of a grid-connected inverter. The system has been simulated to verify its capabilities of buildup voltage, stator flux response, stator phase current, electromagnetic torque, and magnetizing inductance variation during both the dynamic and steady states with a variable-speed prime mover. The complete setup of the above dynamic models was simulated using MATLAB/SIMULINK.

Frequency Spectra of AC Signal Generated from the Operation of Cast-Resin Power Transformer (운전중인 몰드형 전력변압기의 음향방출신호에 대한 주파수 스펙트럼 특성)

  • 구경철;이상우;이동인;이광식;김인식;김이국;신용철
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2000.11a
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    • pp.246-250
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    • 2000
  • In this paper, Frequency spectra of AE(acoustic emission) signals generated from the magnetizing and the load currents in the actual operating cast-resin power transformer of 500[kVA] under distribution system of22.9[kV] were also analysed to distinguish the AE signals due to void discharges from the magnetic circuit noises in the core of cast-resin power transformer. As the experimental results, we could distinguish the AE signals whether those signals were caused due to the void discharges or due to the magnetic circuit noises by analyzing the frequency spectrum of AE signals. Frequency spectra of AE signals generated from the cast-resin power transformer in operation due to both the magnetizing and the load currents appeared in the range of 40-120[khz].

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Development of Statistical Analyzing Tool and System of Automatic Magnetizer (착자 자동화 시스템 및 통계분석 툴 개발)

  • Lee, Cheon-Hui;Ha, Gi-Jong
    • The Transactions of the Korea Information Processing Society
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    • v.3 no.4
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    • pp.1014-1025
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    • 1996
  • The magnetizer that is magnetizing the magnet which is used for RGB (Red Green Blue) control of CRT(Cath-ode-Ray Tube)and the magnet inspection unit which is used for test the state of magnetizing have been imported by magnet manufactures up to now. They are operation by manual now, so that they are needed lots of time and have an increase in probability of malefunction by operator. In this study, we have developed a united system from the magnet production process to inspection ork to automaized a entire progress. Therefor, as we are testing the status of every work and analyzing exactly the distribution in quality with this system, we have known that the reliability of magnetization and magnetized status test has not only increased, but the rate of inferior quality almost not generated.

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An Improved High Efficiency Resonant Converter for the Contactless Power Supply with a Low Coupling Transformer (낮은 커플링 변압기를 갖는 비접촉 전원의 개선된 고효율 공진 컨버터)

  • Kong Young-Su;Kim Eun-Soo;Lee Hyun-Kwan
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.1
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    • pp.33-39
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    • 2005
  • Comparing with the conventional transformer without the air gap, a contactless transformer with the large air gap between the long primary winding and the secondary winding has increased leakage inductance and reduced magnetizing inductance. For transferring the primary power to the secondary one, the high frequency series resonant converter has been widely used for the contactless power supply system with the large air gap and the increased leakage inductance of the contactless transformer However, the high frequency series resonant converter has the disadvantages of the low efficiency and high voltage gain characteristics in the overall load range due to the large air gap and the circulating magnetizing current. In this paper, the characteristics of the high efficiency and unit voltage gain are revealed in the proposed three-level series-parallel resonant converter. The results are verified on the simulation based on the theoretical analysis and the 5kW experimental prototype.

D-q Equivalent Circuit-based Protection Algorithm for a Doubly-fed Induction Generator in the Time Domain

  • Kang, Yong-Cheol;Kang, Hae-Gweon;Lee, Ji-Hoon
    • Journal of Electrical Engineering and Technology
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    • v.5 no.3
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    • pp.371-378
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    • 2010
  • Most modern wind turbines employ a doubly-fed induction generator (DFIG) system due to its many advantages, such as variable speed operation, relatively high efficiency, and small converter size. The DFIG system uses a wound rotor induction machine so that the magnetizing current of the generator can be fed from both the stator and the rotor. We propose a protection algorithm for a DFIG based on a d-q equivalent circuit in the time domain. In the DFIG, the voltages and currents of the rotor side and the stator side are available. The proposed algorithm estimates the instantaneous induced voltages of magnetizing inductance using those voltages and currents from both the stator and the rotor sides. If the difference between the two estimated induced voltages exceeds the threshold, the proposed algorithm detects an internal fault. The performance of the proposed algorithm is verified under various operating and fault conditions using a PSCAD/EMTDC simulator.