• Title, Summary, Keyword: Harmonic analysis

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Thermal Analysis of a High Speed Induction Motor Considering Harmonic Loss Distribution

  • Duong, Minh-Trung;Chun, Yon-Do;Park, Byoung-Gun;Kim, Dong-Jun;Choi, Jae-Hak;Han, Pil-Wan
    • Journal of Electrical Engineering and Technology
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    • v.12 no.4
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    • pp.1503-1510
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    • 2017
  • In this paper, a thermal analysis of a high speed induction motor with a PWM voltage source was performed by considering harmonic loss components. The electromagnetic analysis of the high speed induction motor was conducted using the time-varying finite element method, and its thermal characteristics were carried out using the lump-circuit method. Harmonic losses from tests in the high frequency region were divided into core loss and conductor loss components using various ratios, in order to determine the loss distributions for the thermal analysis. The results from both the calculations and experiment were validated using a high speed induction motor prototype operating at 20,000rpm.

Analysis and Design of a Passive Harmonic Filter for a Three-Phase Rectifier (3상 정류기부하에 대한 수동 고조파필터의 해석 및 설계)

  • Cho, Young-Sik;Cha, Han-Ju
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.3
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    • pp.316-322
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    • 2009
  • This paper presents an analytical design method of a passive harmonic filter for a three-phase diode rectifier and uses a new transfer function approach in the analysis and design. The transfer function approach derives an analytical formulation of an utility system including passive filters with a basis of Laplace transform and provides a graphical formulation so that a visualized insight into an interaction between individual filter and system response can be attainted. Harmonic impedance, voltage division and current division transfer function are used as a design tool, which makes a calculated filter parameters to satisfy IEEE-519 distortion limits. A simple five-step design procedure is introduced in the filter design, which consists of system analysis, selection of PCC(Point of Common Coupling), filter specification calculation, appropriate filter design for system and filter implementation. Philosophy governing the design procedure is based on a numerical/graphical iterative solution, trial and error with visualization feed-back based on "algebra on the graph". Finally, performance of the designed passive harmonic filter is verified by experiment and shows that 5th, 7th, 9th, 11th and 13th harmonics are decreased within IEEE-519 distortion limits, respectively.

Resonance Characteristics Analysis of Grid-connected Inverter Systems based on Sensitivity Theory

  • Wu, Jian;Han, Wanqin;Chen, Tao;Zhao, Jiaqi;Li, Binbin;Xu, Dianguo
    • Journal of Power Electronics
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    • v.18 no.3
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    • pp.746-756
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    • 2018
  • Harmonic resonance exists in grid-connected inverter systems. In order to determine the network components that contribute to harmonic resonance and the composition of the resonant circuit, sensitivity theory is applied to the resonance characteristic analysis. Based on the modal analysis, the theory of sensitivity is applied to derive a formula for determining the sensitivities of each network component parameter under a resonance circumstance that reflects the participation of the network component. The solving formula is derived for both parallel harmonic resonance and series harmonic resonance. This formula is adopted to a 4-node grid-connected test system. The analysis results reveal that for a certain frequency, the participation of parallel resonance and series resonance are not the same. Finally, experimental results demonstrate that the solving formula for sensitivity is feasible for grid-connected systems.

Harmonics Reduction in Load control and Management system

  • Thueksathit, W.;Tipsuwanporn, V.;Hemawanit, P.;Gulpanich, S.;Srisuwan, K.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2283-2286
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    • 2003
  • This paper presents conservation of electrical energy in building with harmonics analysis and compensation which occur in electrical system. We use load controlling and management system in order to adjust load factor of system.The maximum demand limiting and controlling are used ,then the system can acquire the prediction and compare it to the maximum demand set point.The electrical signal analysis based on FFT technique. The harmonics are compensated by using harmonic filters.This system consists computer which works as controller, processor , analysis and database unit together with digital power meter in form of multidrop network through serial communication via RS-485.The load control system uses PLC to control load via serial communication RS-485. The A/D converter is used for sampling the electrical signals via parallel port of computer.The harmonic filters are controlled by a computer.The data of measurement such as voltage, current, power, power factor, total harmonic distortion, energy, etc., can be saved as database and analysis. The load factor is adjusted by limiting and controlling maximum demand. The load factor adjustment can reduce the cost of electric consumption and energy generation together with harmonics compensation in order to increase high efficiency of electrical system.

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Seepage Analysis of Sea Dike under Unsteady State (비정상 상태의 방조제 침투해석)

  • 오남선;이광수
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.13 no.1
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    • pp.35-45
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    • 2001
  • The sea dike at Gun-Jang Industry Area had been constructed recently and both inside and outside areas of the dike show harmonic behaviour. To examine stability against piping, 2 dimensional seepage analysis was executed using finite element method. To investigate the harmonic motion of water level, unsteady and unsaturated flow analysis is needed, and specially harmonic motion in the both areas from the dike should be considered, Water level recorder was used to obtain tidal harmonic data, and sieve analysis has been earried out so that the distribution of grain diameter of the dike material is clearly informed. The calculated velocity was compared with critical velocity.

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The Study of harmonic peaks removal for modal analysis of Rolling tire (Rolling Tire 모드해석을 위한 회전주기성분제거에 대한 연구)

  • Choi, Jeong-Hyun;Lee, Sang-Ju;Park, Ju-Bae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.409-412
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    • 2005
  • Just as the vibration modes of a beam are dependent on its end constraints or boundary conditions. Vibration modes of a tire are dependent on its patch and spindle constraints. This dependence is key to understanding the dynamic properties of a tire and is apparent in various analytical and experimental investigations in the literature. One of the main task in a modal analysis is the measurement of the Frequency Response Function (FRFs). Because all the subsequent analysis is based on these FRFs, their quality is critically important in obtaining accurate modal parameter estimates. In rotating systems, FRFs are frequently contaminated by harmonic peaks related to such factors as imbalance, misalignment. This harmonic peaks appear in the FRFs as sharp spikes, which can be erroneously treated in modal curve-fitting procedures as structural modes. The harmonic peaks removal method is demonstrated by application to modal analysis on rotating tires. The results show substantial improvement in FRF quality.

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A Study on the Analysis of Damping Loads to Prevent Harmonic Resonance (고조파 공진 억제를 위한 완충부하 투입량 분석에 관한 연구)

  • Lim, Chan-Ho;Lee, Kyeong-Seob;Yu, Won-Kun;Lee, Heung-Jae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.2
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    • pp.262-266
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    • 2010
  • During the restoration process of primary restorative transmission system, the over voltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This over voltage is caused by harmonic resonance and can be prevented by damping loads that are connected before restoration process of primary restorative transmission system. But it is very difficult to predict the occurrence possibility of the harmonic resonance previously. This paper analyzes the relationship between the harmonic resonance and the amount of damping loads to prevent the harmonic resonance. This paper calculates the minimum amount of damping loads to prevent harmonic resonance while changing the length of primary restorative transmission line. And this paper confirmed that the amount of damping loads is not proportional to length of transmission line. The result of this paper will be used as important experiment data to predict the occurrence possibility of harmonic resonance previously.

Leakage Current Waveforms and Spectrum Analysis of EPDM Polymer Insulator according to Environment Condition (환경조건에 따른 EPDM 고분자 애자의 누설전류파형과 스펙트럼 분석)

  • Park, Jae-Jun;Kim, Jeong-Boo;Song, Young-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.82-86
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    • 2004
  • This research is about the result of leakage current waveform about the situation of surface leakage current and environmental changes(Salt fog, clean fog and rain) by EPDM polymer insulators' amount of salt. The researcher presents the result of changing about fundamental harmonic, 3rd harmonic and 5th harmonic from starting point of supplying power to flashover. In this study, researched environmental affects (clean fog, salt fog and rain) about surface aging of polymer insulators and used frequency spectrum of leakage current waveform to develop the diagnostic technique of surface aging. When amount of salt contents changed, surface aging stage and the degree of aging (distortion factor) about 3rd and 5th harmonic waveform on low frequency harmonic wave. The distortion factor which is harmonic percentage about basic harmonic is important pointer to evaluate the surface condition of polymer insulators.

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Injection Locked Synchronization Characteristics of a Millimeter Wave Second Harmonic Oscillator (밀리미터파 대역 제2고조파 출력 발진기의 주입동기 특성)

  • Choi, Young-Kyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1700-1705
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    • 2013
  • A second harmonic millimeter wave oscillator utilizing sub-harmonic injection-synchronization is presented. A 8.7GHz oscillator with MES-FET is designed, and is driven as a harmonic output oscillator at 17.4GHz by means of sub-harmonic injection-synchronization. The oscillator operates as a multiplier as well as a oscillator in this scheme. Adopting this method, a high sable, high frequency millimeter wave source is obtainable even though self-oscillating frequency of an oscillator is relatively low. The range of injection-synchronization is about 26MHz, and is proportional to the input sub-harmonic power. The spectrum analysis of the 2nd harmonic output frequency shows remarkably decreased the phase noise level.