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Uniformly excited, equally-spaced linear arrays do not provide side lobe levels below − 13.3 dB, and thus are less desirable in applications requiring lower side lobe levels. We present an efficient method for side lobe reduction in these arrays with little penalty on the directivity. The method involves the following steps: construction of a periodic function containing only the side lobes of the...
This paper introduces two online methods for optimal periodic control (OPC) of open-loop stable plants. The first method requires knowledge of the plant structure but allows for uncertainty in plant parameters. It employs recursive least squares to estimate parameters, then uses the estimates to adapt the shape of the optimal trajectory. The second method uses a model-free extremum seeking scheme...
IEEE Standard 1459 defines the power components based on the fast Fourier series. However, Fourier series assumes the signal is periodic in nature, and provides erroneous assessment of the power components in the presence of transient signals. Therefore, a new method is proposed for the evaluation of the IEEE Standard 1459 power components based on the time-frequency distribution (TFD) and the cross...
The magnetic flux density of an induction machine is a combination of space harmonics due to the fundamental magneto motive force and slot harmonics due to slots in both rotor and stator. Accurate determination of effects of slot harmonics on air-gap magnetic field is essential for analytical modeling of an induction machine. In the Literature, the relation to determine order of slot harmonics present...
Due to difficult establishment of flux linkage model caused by magnetic highly saturation when Switched Reluctance Motor (SRM) operates. A new nonlinear flux linkage model (flux linkage model) for SRM is proposed in this paper. This paper used the Gauss function modeled three special position flux curve, and combined with Fourier series to get other position flux curve, then compared with the measured...
This paper presents a novel spectral analysis technique for multilevel modulation. Conventionally, such analyses use a Double Fourier series technique, but this approach can become intractable when complex reference waveforms (e.g. multilevel space vector offsets) and regular sampling processes are considered. In contrast, the strategy proposed in this paper separates the multilevel pulse width modulation...
Ratio of the electromagnetic torque section of the brushless motor with a nonmagnetic armature on interval switching has been calculated and its general expression under 180 degree law switching has been defined. Estimation of electromagnetic torque ripple caused by discrete switching sections of the armature winding has been provided.
In this research, a generic analytical model of voltage response of fractance in time domain which is often cited in various disciplines such as control engineering and electronic engineering etc., has been proposed. This model can be applied to fractance of any order under any type of current excitation. So, it has been found to be beneficial to various fractance involved disciplines stated above...
We describe the norm of Fourier operator from Lp(T) to lq(ℤ), and from lp(ℤ) to Lq(T) for all p, q ≥ 1, motivated by the problem of finding sharp uncertainty principles expressed in terms of Rényi entropies.
The present work presents a learning platform focused on the analysis of thin rectangular plates, which main objectives beyond the prediction of the mechanical behaviour of these structures, are the improvement of the perception of the physical phenomena and the parameters involved in the evaluation of the structural model. The platform developed allows studying homogeneous and non homogeneous rectangular...
Among other things, E. A. Guillemin is known for solving the Gibbs phenomenon relating to Fourier series components when combined to create step-function outputs. His work is frequently cited in the design of type A, B, C, D, and E pulse-forming networks (PFNs). The synthesis of type A, B and C networks is straightforward using Cauer or partial-fraction expansion techniques and the driving-point admittance...
Ultra-wide band (UWB) systems require either rapidly changing or very high sampling rates. Conventional analog-to-digital devices have limited dynamic range. We investigate UWB signal processing via a basis projection method and a basis system designed for UWB signals. The method first windows the signal and then decomposes the signal into a basis via a continuous-time inner product operation, computing...
With the emergence of renewable energy power generation, varied kinds of DC-AC inverters based on SPWM control including photovoltaic (PV) inverters have been widely applied in practice. However, high-frequency operations of switches under traditional SPWM (TSPWM) will lead to obvious EMI peaks on switching frequency and its multiples, which may cause serious electromagnetic interference (EMI) problem.
The paper discusses the influence of a dead time duration on the input current spectrum of voltage-source active rectifiers. The main body shows the simulations of a three-phase voltage-source active rectifier with respects to the dead times. This section especially describes the figures which present the harmonics analysis of the input current and its dependence on the dead time duration. The last...
This paper presents a spectrum-based method to estimate the integral non-linearity (INL) of an analog-to-digital converter. It relies on a previous work published in the literature that consists in expanding in Fourier series the analytical expression of a converter distorted signal output. The INL estimation process is then reduced to three operations: a discrete Fourier transform (DFT), a matrix...
Several sampling theorems for deterministic signals are known to have their counterparts for stochastic signals. Motivated by Kramer's result on generalized sampling of band-limited deterministic signals, we obtain generalized sampling expansions of a certain class of stochastic processes which are not necessarily wide sense stationary.
Differential equations play a noticeable role in engineering, physics, economics, and other disciplines. In this paper, a general approach is suggested to solve a variety of linear and nonlinear ordinary differential equations (ODEs). With the aid of certain fundamental concepts of mathematics, Fourier series expansion and metaheuristic optimization methods, ODEs can be represented as an optimization...
This paper intends to examine the capability of detecting field winding short circuits in round rotor synchronous machines through the terminal voltage harmonic analysis. A time-based approach is developed, and several machine configurations are simulated in normal condition and in the presence of a rotor fault to find expected induced voltages and analyze the method sensitivity. Comparisons indicate...
A major source for torque ripple is the harmonics in airgap permeance caused by stator slotting, permanent magnet (PM) flux barrier, etc. They are reflected in the flux linkages of the stator windings. In this work, we express the d and q-axis flux linkages as Fourier series after obtaining them using finite element analysis (FEA). Torque ripples are obtained analytically using the Fourier coefficients...
In this paper, model sets for continuous-time linear time invariant systems that are spanned by fixed pole orthonormal bases are investigated. These bases generalise the well known Laguerre and Kautz bases. It is shown that the obtained model sets are complete in all of the Hardy spaces Hp(Π), 1 ≤ p < ∞ and the right half plane algebra Α(Π) provided that a mild condition on the choice of basis...
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