Topic
Harmonic
About: Harmonic is a research topic. Over the lifetime, 44833 publications have been published within this topic receiving 495922 citations. The topic is also known as: overtone & partial.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, a frequency domain arc furnace model for iterative harmonic analysis by means of a Newton method is presented, which offers a three-phase configuration where there is no path for homopolar currents.
Abstract: This paper presents a new frequency domain arc furnace model for iterative harmonic analysis by means of a Newton method. Powerful analytical expressions for harmonic currents and their derivatives are obtained under balanced conditions of the power system. The model offers a three-phase configuration where there is no path for homopolar currents. Moreover, it contemplates continuous and discontinuous evolution of the arc current. The solution obtained is validated by means of time domain simulations. Finally, the model was integrated in a harmonic power flow where studies have been performed in a network with more than 700 busbars and 7 actual arc furnace loads.
93 citations
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TL;DR: An intense, nonresonant femtosecond laser pulse superimposed with its phase-controlled second harmonic field is used to impulsively align and orient a dense sample of molecules from which high-order harmonics are generated.
Abstract: We study the emission of even and odd high-harmonic orders from oriented OCS molecules. We use an intense, nonresonant femtosecond laser pulse superimposed with its phase-controlled second harmonic field to impulsively align and orient a dense sample of molecules from which we subsequently generate high-order harmonics. The even harmonics appear around the full revivals of the rotational dynamics. We demonstrate perfect coherent control over their intensity through the subcycle delay of the two-color fields. The odd harmonics are insensitive to the degree of orientation, but modulate with the degree of axis alignment, in agreement with calculated photorecombination dipole moments. We further compare the shape of the even and odd harmonic spectra with our calculations and determine the degree of orientation.
93 citations
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TL;DR: In this article, a nonlinear and fractional derivative viscoelastic (FDV) model is used to capture the complex behavior of rail pads and is implemented into the dynamic analysis of coupled vehicle-slab track (CVST) systems.
93 citations
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08 May 2006TL;DR: This paper examines the behavior of three phase induction motors with internal fault conditions under sinusoidal and nonsinusoidal supply, which includes rotor broken bar, and stator faults.
Abstract: This paper examines the behavior of a three-phase induction motors with internal fault conditions under sinusoidal and nonsinusoidal supply voltages. This includes two types of faults, rotor broken bar and stator faults. Early detection and diagnosis of these faults are desirable for condition assessment, maintenance schedule, and improved operational efficiency of induction motors. The terminal behavior of the induction motor was investigated by coupling the induction motor transient finite-element (FE) model and external electric circuit. Such a model would allow the efficient representation of the induction machine with internal faults. A discrete wavelet transform (DWT) was then used to extract the different harmonic components of the stator currents. The key advantages of the DWT are its ability to provide a local representation (in both time and frequency) of the current signal for normal and faulty modes, and its applicability to nonstationary signals
93 citations
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TL;DR: The proposed method is based on spectral preprocessing of the stator current followed by subspace decomposition of the signal autocorrelation matrix to detect relatively low-amplitude fault sidebands and is found to be very effective in detecting low-AMplitude sinusoids in a signal dominated by high-amPLitude fundamental.
Abstract: This paper presents an effective method of motor current signature analysis for detecting half- as well as full broken single rotor bar fault of a squirrel-cage induction machine under various loading conditions and speeds. The proposed method is based on spectral preprocessing of the stator current followed by subspace decomposition of the signal autocorrelation matrix to detect relatively low-amplitude fault sidebands. This method is found to be very effective in detecting low-amplitude sinusoids in a signal dominated by high-amplitude fundamental. The extended Kalman filter is used to estimate and track the fundamental component of the stator current. This component is subtracted from the measured stator current at every time step generating a resultant signal with a very low or negligible fundamental component. Subsequently, multiple-signal classification (MUSIC) is applied on the resultant stator current signal. Motor slip is estimated from principle slot harmonic to decide the approximate location of the fault sidebands. For effective fault detection, a hypothesis test is proposed to check the presence of sufficient fault frequency sideband in the current spectrum. This test works better if the lobe in the MUSIC plot due to the fault frequency is not distorted or overlapped by the fundamental component. Therefore, for each data window, the minimum size of the autocorrelation matrix is determined to generate distinct peaks. The proposed method applies to steady-state condition and is found to exhibit superior performance even during the light-load conditions with a half-broken bar.
93 citations