Wavelets and T-Pulses

Sarkar, Tapan K.; Wang, H.; Wicks, Michael C.; Salazar‐Palma, Magdalena

doi:10.1007/978-1-4899-1394-4_50

Cited by 9 publications

(15 citation statements)

References 3 publications

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“…The wavelet theory states that every sampled signal s (s 1 , s 2 , …s N ) can be approximated by the sum of an approximation signal a n and some detail signals d j [17,[20][21], according to (2)…”

Section: Phenomenon Description and Proposed Approachmentioning

confidence: 99%

“…are the scaling and wavelet coefficients respectively, φ n (t), ψ j (t) are the scaling function at level n and wavelet function at level j respectively, and n is the decomposition level. a n is the approximation signal at level n and d j is the detail signal at level j [20][21]. Mallat algorithm shows that each signal is associated with a certain frequency band.…”

Section: Phenomenon Description and Proposed Approachmentioning

confidence: 99%

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Validation of a new method for the diagnosis of rotor bar failures via wavelet transform in industrial induction machines

Antonino-Daviu

Riera-Guasp

Folch

et al. 2006

IEEE Trans. on Ind. Applicat.

282

191

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In this paper, the authors propose a method for the diagnosis of rotor bar failures in induction machines, based on the analysis of the stator current during the startup using the Discrete Wavelet Transform (DWT). Unlike other approaches, the study of the high-order wavelet signals resulting from the decomposition is the core of the proposed method. After an introduction of the physical and mathematical basis of the method, a description of the proposed approach is given; for this purpose, a numerical model of induction machine is used, in such a way that the effects of a bar breakage can clearly be shown, avoiding the influence of other phenomena not related with the fault. Afterwards, the new diagnosis method is validated using a set of commercial induction motors. Several experiments are developed under different machine conditions (healthy machine and machine with different levels of failure) and operating conditions (no load, full-load, pulsating load and fluctuating voltage). In each case, the results are compared with those obtained using the classical approach, based on the analysis of the steady-state current using the Fourier Transform. Finally, the results are discussed and some considerations about the influence of the DWT parameters (type of mother wavelet, order of the mother wavelet, sampling rate or number of levels of the decomposition) over the diagnosis are done.

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Section: Phenomenon Description and Proposed Approachmentioning

confidence: 99%

Section: Phenomenon Description and Proposed Approachmentioning

confidence: 99%

Validation of a new method for the diagnosis of rotor bar failures via wavelet transform in industrial induction machines

Antonino-Daviu

Riera-Guasp

Folch

et al. 2006

IEEE Trans. on Ind. Applicat.

282

191

View full text Add to dashboard Cite

show abstract

“…In the last years, the expansion of integro-differential equations (characteristics of electromagnetic problems) on wavelet bases (from this point forward briefly indicated as WE) has become a known and used tool in electrical engineering [15], [16]. The main reason comes from the fact that expanding these equations on a wavelet basis gives algebraic systems that can be conveniently solved (by numerical techniques) giving accurate results in a low CPU time.…”

Section: Wavelet-based Representation Of Electromagnetics Equationsmentioning

confidence: 99%

“…Here, we propose the following different approach, based on the previous definition of the vectors : we define the upper bound as related to a set of distributed power waves constructed by adding up together the absolute values of the previously calculated vectors (14) In this way, it is possible to obtain the upper bound of the response straightforward (from (6)), as (15) The previous equation can be also written as , leading to the following lower bound: (16) which must be inverse transformed giving the time-domain bounds of the power waves.…”

Section: Representation Of Plc Channels By Wavelet-based Scattermentioning

confidence: 99%

Innovative model for time-varying power line communication channel response evaluation

Barmada

Musolino

Raugi

2006

IEEE J. Select. Areas Commun.

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Abstract-This work presents a channel model for the broadband characterization of power lines in presence of time variation of the loads. The model is characterized by taking into account both measured and geometrical channel characteristics and can easily be used to take into account also the presence of noise. The channel is described by a two-port equivalent described by a scattering matrix determined from a wavelet-based expansion of the input and output quantities. Upper and lower bounds for the response of the channel in presence of time-varying loads are determined in a fast and efficient way avoiding time consuming Monte Carlo simulations. The bounds determination allows the estimate of noteworthy quantities for the tuning of currently used modulation schemes for power lines communications such as orthogonal frequency-division multiplexing.

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“…In the past twenty years, several applications of wavelets in the wave propagation domain have been studied. Wavelets applied to integral equations [31,32] and time-domain methods [33,34,35,32] have been proposed to improve their computational efficiency. In integral equations in electromagnetics, wavelets are notably used to transform a full-matrix linear system into a sparse one.…”

Section: Introductionmentioning

confidence: 99%

Modeling the long-range wave propagation by a split-step wavelet method

Zhou

Douvenot

Chabory

2020

Journal of Computational Physics

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A split-step wavelet method for simulating the long-range wave propagation is introduced. It is based on the fast wavelet transform. Compared to the split-step Fourier method, this method improves the computation efficiency while keeping a good accuracy. The propagation is performed iteratively by means of a pre-computed matrix containing the individual propagations of the wavelets. A fast computation method of this matrix is also presented. For the radiowave propagation in the low troposphere, a local image method is proposed to account for an impedance ground. Inhomogeneous atmospheres and irregular grounds are also considered. Finally, numerical tests of long-range propagations are performed to show the accuracy and time efficiency of this method.

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Wavelets and T-Pulses

Cited by 9 publications

References 3 publications

Validation of a new method for the diagnosis of rotor bar failures via wavelet transform in industrial induction machines

Validation of a new method for the diagnosis of rotor bar failures via wavelet transform in industrial induction machines

Innovative model for time-varying power line communication channel response evaluation

Modeling the long-range wave propagation by a split-step wavelet method

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