• Title, Summary, Keyword: Main electromagnetic parameter

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A Fundamental Study on Magnetic Pulse Forming with Bar Forming Coil (Bar 성형 코일을 이용한 전자기 성형에 관한 기초 연구)

  • Shim, Ji-Yeon;Kang, Bong-Yong;Park, Dong-Hwan;Kim, Ill-Soo
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.20 no.3
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    • pp.292-297
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    • 2011
  • MPF(Magnetic pulse forming) process refers to the high velocity and high strain rate deformation of a low-ductility materials driven by electromagnetic forces that are generated by the rapid discharge current through forming coil. The goal of this study was to find the characteristics of dynamic behavior of workpiece and to find the main design process on MPF using bar forming coil. For these purposes, thin Al5053 sheet were used for the experiment. The measured strain data were analyzed by developed electromagnetic FE-model. The main design parameter is location of coil, electromagnetic force. In case of the bar forming coil, there exists the dead regions where the low electromagnetic force applied on the workpiece.

Field Circuit Coupling Optimization Design of the Main Electromagnetic Parameters of Permanent Magnet Synchronous Motor

  • Zhou, Guang-Xu;Tang, Ren-Yuan;Lee, Dong-Hee;Ahn, Jin-Woo
    • Journal of Electrical Engineering and Technology
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    • v.3 no.1
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    • pp.88-93
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    • 2008
  • The electromagnetic parameters of a permanent magnet synchronous motor (PMSM) such as the open load permanent magnet flux, d axis reactance $X_d$, and q axis reactance $X_q$, are most essential to the performance analysis and optimization design of the motor. Based on the numerical analysis of the 3D electromagnetic field, the three electromagnetic parameters of permanent magnet synchronous motors with U form interior rotor structures are calculated by FEA. The rules of the leakage coefficient and reactance parameters changing with the air gap length, permanent magnet magnetism length, and isolation magnetic bridge dimensions in the rotor are given. The calculated values agree well with the measured values. The FEA results are integrated with the self compiled electromagnetic design program to optimize the prototype motor. The tested performances of the prototype motor prove that the method is suitable for the optimization of motor structure.

RAKE Receiver for Time Division Synchronous CDMA Mobile Terminal

  • Xiao Yang;Lee Kwang-Jae;Lee Moon-Ho
    • Journal of electromagnetic engineering and science
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    • v.6 no.1
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    • pp.10-17
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    • 2006
  • For the sake of the potential ability of overcoming interference in TD-SCDMA(time division-synchronous code division multiple access) systems, pilot signal is adopted, but the presented TD-SCDMA protocol has not considered the Rake technique for their mobile terminals. This paper developed a RAKE receiver algorithm and an implementation circuit, which make use of the pilot signal in the burst structure of the TD-SCDMA base station to estimate main channel parameter(channel delays) in the downlink of TD-SCDMA wireless network. The algorithm can reduce multipath interference for the mobile units in multiusers' case. Theoretic performance analysis presented in the paper and computer simulations show that there is a range of BER for Rake receiver and confirm that the proposed RAKE receiver algorithm achieved a better performance under multipath fading propagation and multiusers conditions.

A Study on Isolation Improvement of LTE-PIFA Used Stub Structure on Ground Plane (접지면 위의 스터브를 이용한 LTE-PIFA의 격리도 개선 연구)

  • Park, Chan-Jin;Min, Kyoeng-Sik
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.4
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    • pp.374-383
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    • 2013
  • This paper presents a design for improvement of isolation characteristics by the inserted stub structure on ground plane of a handy terminal which is composed of a main antenna and a sub antenna covered LTE bandwidth. In order to compensate for a resonance length of proposed antenna and to realize a high isolation characteristic, a pair of stub was inserted and located on ground plane that currents from two antennas were converged. A simulated isolation characteristic of antenna without stub at the LTE class 13 band was about -5 dB, but its characteristics of proposed antenna with two stubs at uplink(777~787 MHz) and downlink(746~756 MHz) of the LTE class 13 band were about -12 dB and -15 dB, respectively. An average gain of a fabricated antenna with two stubs was observed about -2 dBi above and it showed good results with comparison of business condition that the average gain of commercial handy terminal has to appear -4 dBi above. The measured S-parameter characteristics and radiation patterns showed a reasonable agreement with the simulation results.

EMI Noise Source Reduction of Single-Ended Isolated Converters Using Secondary Resonance Technique

  • Chen, Zhangyong;Chen, Yong;Chen, Qiang;Jiang, Wei;Zhong, Rongqiang
    • Journal of Power Electronics
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    • v.19 no.2
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    • pp.403-412
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    • 2019
  • Aiming at the problems of large dv/dt and di/dt in traditional single-ended converters and high electromagnetic interference (EMI) noise levels, a single-ended isolated converter using the secondary resonance technique is proposed in this paper. In the proposed converter, the voltage stress of the main power switch can be reduced and the voltage across the output diode is clamped to the output voltage when compared to the conventional flyback converter. In addition, the peak current stress through the main power switch can be decreased and zero current switching (ZCS) of the output diode can be achieved through the resonance technique. Moreover, the EMI noise coupling path and an equivalent model of the proposed converter topology are presented through the operational principle of the proposed converter. Analysis results indicate that the common mode (CM) EMI noise and the differential mode (DM) EMI noise of such a converter are deduced since the frequency spectra of the equivalent controlled voltage sources and controlled current source are decreased when compared with the traditional flyback converter. Furthermore, appropriate parameter selection of the resonant circuit network can increase the equivalent impedance in the EMI coupling path in the low frequency range, which further reduces the common mode interference. Finally, a simulation model and a 60W experimental prototype of the proposed converter are built and tested. Experimental results verify the theoretical analysis.

High Pass Filter Design Using Folded Coplanar Waveguide CRLH Transmission Line

  • Yang, Lei;Yang, Doo-Yeong
    • International Journal of Contents
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    • v.11 no.3
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    • pp.63-68
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    • 2015
  • A novel unit cell for a high pass filter was designed based on a composite right/left-handed structure that uses a folded coplanar waveguide. The equivalent circuit model for the unit cell was extracted from the geometry of the unit cell, and the effect of each main parameter of the unit cell was analyzed. The equations to calculate the immittance values of the equivalent circuit elements were formulated, and moreover, the dispersion characteristics and energy the distributions of the electromagnetic fields were simulated to determine the characteristics of the composite right/left-handed structure. Finally, the high pass filters were implemented as a series of the proposed unit cells. We show that the experimental results were in good agreement with those obtained from the simulation. Thus, the high pass filter was found to achieve a baseband insertion loss of 3 dB and a stopband attenuation of 70 dB.

An Effective Method for Selection of WGN Band in Man Made Noise(MMN) Environment (인공 잡음 환경하에서의 효율적인 백색 가우시안 잡음 대역 선정 방법)

  • Shin, Seung-Min;Kim, Young-Soo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.11
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    • pp.1295-1303
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    • 2010
  • In this paper, an effective method has been proposed for selection of white Gaussian noise(WGN) band for radio background noise measurement system under broad band noise environment. MMN which comes from industrial devices and equipment mostly happens in the shape of broad band noise mostly like impulsive noise and this is the main reason for increasing level in the present radio noise measurements. The existing method based on singular value decomposition has weak point that it cannot give good performance for the broad band signal because it uses signal's white property. The proposed method overcomes such a weakness of singular value decomposition based method by using signal's Gaussian property based method in parallel. Moreover, this proposed method hires a modelling based method which uses parameter estimation algorithm like maximum likelihood estimation(MLE) and gives more accurate result than the method using amplitude probability distribution(APD) graph. Experiment results under the natural environment has done to verify feasibility of the proposed method.

Simulator for High Resolution Synthetic Aperture Radar Image Formation and Image Quality Analysis (고해상도 SAR 영상 형성 및 품질 분석을 위한 시뮬레이터)

  • Jung, Chul-Ho;Oh, Tae-Bong;Kwag, Young-Kil
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.8
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    • pp.997-1004
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    • 2007
  • High resolution synthetic aperture radar image could be sensitive to the various parameters of the payload, platform, and ground system. In this paper, a parameter based SAR simulator is presented for two-dimensional image formation and image quality analysis. Functional modules are implemented by Matalb code and GUI for the flexibility and expandability. Main function of this simulator includes the SAR input signal generation, range-doppler algorithm(RDA) based SAR image formation, and the SAR image quality analysis which is relevant to the SAR system design parameters. This simulator can effectively be used for the SAR image quality performance evaluation, which can be applicable to the airborne as well as spaceborne SAR system design and analysis.

SAR Data Correction Based on Calibrated-Scatterometer Measurements (보정된 Scatterometer의 측정데이터를 사용한 SAR 데이터 교정)

  • 정구준;홍진영;오이석
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.2
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    • pp.121-126
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    • 2004
  • This paper presents an SAR-data calibration technique using a well-calibrated scatterometer. At first a fully-polarimetric antenna pattern(magnitude and phase) of the antenna main-beam using a conducting sphere was measured. Then, this data were used to calibrate polarimetrically an auto-mounted network analyzer-based scatterometer system. This scatterometer system can be used to measure the accurate Mueller matrices of earth surfaces such as grass fields, rice fields and bare soil surfaces; i.e., the phase-difference parameters can be obtained as well as the radar scattering coefficients. If a polarimetrically calibrated scatterometer is operated at the same time with the SAR system, the scatterometer data can be used to correct the SAR data, especially the phase-difference parameters. It was found that the correction effect is remarkable for the degree of correlation ${\alpha}$, which is one of the phase-difference parameter, while the correction effect is negligible for the magnitude parameters(backscattering coefficients).

A Study on 3[kW] PMA-RSG Optimal Design for Mobile Power Supply (이동형 전원장치용 3[kW] PMA-RSG의 최적 설계에 대한 연구)

  • Baik, Jei-Hoon;Toliyat, Hamid A.;Kim, Nam-Hun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.6
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    • pp.109-117
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    • 2009
  • In this paper, an analytical model using equivalent magnetic circuits for the PMA-SynRG is presented. The lumped parameter model (LPM) is developed from machine geometry, stator winding and machine operating specifications. By the LPM, magnetic saturation of rotor bridges is incorporated into model and it provides effective means of predicting machine performance for a given machine geometry. The LPM is not as accurate as finite element analysis but the equivalent magnetic circuits provide fast means of analyzing electromagnetic characteristics of PMa-SynRG. It is the main advantage to find the initial design and optimum design. The initial design of PMa_RSG is performed by LPM model and FEM analysis, and the final PMA-RSG design is optimized and identified by FEM analysis considering actual machine design. The linear LPM and the nonlinear LPM are programmed using MATLAB and all of machine parameters are calculated very quickly. To verify justification of the proposed design of PMa-RSM, back-EMF is measured.