A simple maximum power point tracking based control strategy applied to a variable speed squirrel cage induction generator

This paper presents a comprehensive modelling and control study of a variable speed wind energy conversion system based on a squirrel-cage induction generator (SCIG). The mathematical model of the SCIG is derived in Park frame along with the indirect field oriented control (IFOC) scheme based on a proportional and integral speed controller. A simple maximum power point tracking strategy is used to determine the optimal speed under variable wind speed conditions which is then used as the reference in the IFOC scheme. Power flow between the supply and the inverter is regulated via simultaneous control of the active and reactive currents of the grid and the DC link voltage. The simulation results show that the proposed control technique is able to maximise the energy extracted from the wind during the simulation scenarios considered. The results also demonstrate good transient response characteristics in the decoupled real and reactive powers.Peer reviewedFinal Accepted Versio

Diagnosis of rotor fault using neuro-fuzzy inference system

The three-phase induction machines (IM) is large importance and are being widely used as electromechanical system device regarding for their robustness, reliability, and simple design with well developed technologies. This work presents a reliable method for diagnosis and detection of rotor broken bars faults in induction machine. The detection faults are based on monitoring of the current signal. Also the calculation of the value of relative energy for each level of signal decomposition using package wavelet, which will be useful as data input of adaptive Neuro-Fuzzy inference system (ANFIS). In this method, fuzzy logic is used to make decisions about the machine state. The adaptive Neuro-Fuzzy inference system is able to identify the IM bearing state with high precision. This technique is applied under the MATLAB®.Keywords: Induction Machine; Diagnosis; Detection; Neuro-Fuzzy inference system

THE SYNDROME OF OVERTRAINING AMONG THE ALGERIAN ELITE JUDOKAS (YOUNGER MEMBERS OF THE ALGERIAN NATIONAL TEAM) DURING A COMPETITION FOLLOW-UP

Introduction:  The main objective of this study is to detect the existence of a state of fatigue and a syndrome of overtraining among Algerians judokas of the youngest category (girls and boys) by the use of the questionnaire of fatigue among the child athlete (QFES) and to evaluate the variations of the score by report has its 07 dimensions. Method: 24 judokas cadets of the national team, 14 boys 58.3% and 10 girls 41,7%. The boys are an average age of 16.21±0.21 years, an average weight of 67±16,40kg and a stature of 171,64±9,49cm. They have a body mass index(BMI) of 22.69±4.94 kg/m².girls have an average age of 16.20±0.78 years, a weight of 59.1±7.89 kg and a stature of 163.9±3,14cm.The BMI is equal to 21,95±2.50 kg/sq. m. The athletes are attending school between the fourth average year at the College and the second year of secondary school. During the period of the microcycle stage of competition which is taking place between 01 March 2017 and 31 May 2017, we distributed the questionnaire at the end of the competition at the Championship in Algeria (Algiers, 27/05/2017). Results: The score of the questionnaire was to 40.01±8.58 (minimum=27, 00, maximum=54), 33.33% of athletes their scores to the QFES≥45. The average score for an item is 1.1±0.11. The ranking of items of the QFES by average quotation with significant threshold retained of p<0.05. The results are expressed in average ± standard deviation. Conclusion: The main results show that in the questionnaire QFES fatigue is a sensitive tool to detect a state of fatigue. However, a biological study is imperative in order to establish the correlation between syndrome of the overtraining and oxidative stress among young judokas  Article visualizations

Ion impact induced Interatomic Coulombic Decay in neon and argon dimers

We investigate the contribution of Interatomic Coulombic Decay induced by ion impact in neon and argon dimers (Ne$_2$ and Ar$_2$) to the production of low energy electrons. Our experiments cover a broad range of perturbation strengths and reaction channels. We use 11.37 MeV/u S$^{14+}$, 0.125 MeV/u He$^{1+}$, 0.1625 MeV/u He$^{1+}$ and 0.150 MeV/u He$^{2+}$ as projectiles and study ionization, single and double electron transfer to the projectile as well as projectile electron loss processes. The application of a COLTRIMS reaction microscope enables us to retrieve the three-dimensional momentum vectors of the ion pairs of the fragmenting dimer into Ne$^{q+}$/Ne$^{1+}$ and Ar$^{q+}$/Ar$^{1+}$ (q = 1, 2, 3) in coincidence with at least one emitted electron

Time Ordering in Kicked Qubits

We examine time ordering effects in strongly, suddenly perturbed two-state quantum systems (kicked qubits) by comparing results with time ordering to results without time ordering. Simple analytic expressions are given for state occupation amplitudes and probabilities for singly and multiply kicked qubits. We investigate the limit of no time ordering, which can differ in different representations.Comment: 26 pages, 5 figure

Multivariable control of a grid-connected wind energy conversion system with power quality enhancement

This document is the Accepted Manuscript version of the following article: Kaddour Fouad, Houari Merabet Boulouiha, Ahmed Allali, Ali Taibi, and Mouloud Denai, ‘Multivariable control of a grid-connected wind energy conversion system with power quality enhancement’, Energy Systems, Vol. 9 (1): 25-57, February 2018. The final publication is available at Springer via: https://doi.org/10.1007/s12667-016-0223-7This paper proposes the design of a multivariable robust control strategy for a variable-speed WECS based on a SCIG. Optimal speed control of the SCIG is achieved by a conventional PI controller combined with a MPPT strategy. DTC-SVM technique based on a simple Clarke transformation is used to control the generator-side three-level converter in the variable speed WECS. The flow of real and reactive power between the inverter and the grid is controlled via the grid real and reactive currents and the DC link voltage using multivariable H∞ control. The overall WECS and control scheme are developed in Matlab/Simulink and the performance of the proposed control strategy is evaluated via a set of simulation scenarios replicating various operating conditions of the WECS such as variable wind speed and asymmetric single grid faults. The power quality of the WECS system under H∞ control control approach is assessed and the results show a significant improvement in the total harmonic distorsion as compared to that achieved with a classical PI control.Peer reviewedFinal Accepted Versio

Correlation dynamics between electrons and ions in the fragmentation of D2_2 molecules by short laser pulses

We studied the recollision dynamics between the electrons and D$_2^+$ ions following the tunneling ionization of D$_2$ molecules in an intense short pulse laser field. The returning electron collisionally excites the D$_2^+$ ion to excited electronic states from there D$_2^+$ can dissociate or be further ionized by the laser field, resulting in D$^+$ + D or D$^+$ + D$^+$, respectively. We modeled the fragmentation dynamics and calculated the resulting kinetic energy spectrum of D$^+$ to compare with recent experiments. Since the recollision time is locked to the tunneling ionization time which occurs only within fraction of an optical cycle, the peaks in the D$^+$ kinetic energy spectra provides a measure of the time when the recollision occurs. This collision dynamics forms the basis of the molecular clock where the clock can be read with attosecond precision, as first proposed by Corkum and coworkers. By analyzing each of the elementary processes leading to the fragmentation quantitatively, we identified how the molecular clock is to be read from the measured kinetic energy spectra of D$^+$ and what laser parameters be used in order to measure the clock more accurately.Comment: 13 pages with 14 figure

Leptoproduction of J/psi

We study leptoproduction of $J/\psi$ at large $Q^2$ within the nonrelativistic QCD (NRQCD) factorization formalism. The cross section is dominated by color-octet terms that are of order $\alpha_s$. The color-singlet term, which is of order $\alpha^2_s$, is shown to be a small contribution to the total cross section. We also calculate the tree diagrams for color-octet production at order $\alpha^2_s$ in a region of phase space where there is no leading color-octet contribution. We find that in this regime the color-singlet contribution dominates. We argue that non-perturbative corrections arising from diffractive leptoproduction, higher twist effects, and higher order terms in the NRQCD velocity expansion should be suppressed as $Q^2$ is increased. Therefore, the color-octet matrix elements $$and$$ can be reliably extracted from this process. Finally, we point out that an experimental measurement of the polarization of leptoproduced $J/\psi$ will provide an excellent test of the NRQCD factorization formalism.Comment: 33 pages latex. 10 figures. Uses revtex, epsf, and rotate macros. This paper is also available via the UW phenomenology archives at http://phenom.physics.wisc.edu/pub/preprints

High Performance Multicell Series Inverter-Fed Induction Motor Drive

This document is the Accepted Manuscript version of the following article: M. Khodja, D. Rahiel, M. B. Benabdallah, H. Merabet Boulouiha, A. Allali, A. Chaker, and M. Denai, ‘High-performance multicell series inverter-fed induction motor drive’, Electrical Engineering, Vol. 99 (3): 1121-1137, September 2017. The final publication is available at Springer via DOI: https://doi.org/10.1007/s00202-016-0472-4.The multilevel voltage-source inverter (VSI) topology of the series multicell converter developed in recent years has led to improved converter performance in terms of power density and efficiency. This converter reduces the voltage constraints between all cells, which results in a lower transmission losses, high switching frequencies and the improvement of the output voltage waveforms. This paper proposes an improved topology of the series multicell inverter which minimizes harmonics, reduces torque ripples and losses in a variable-speed induction motor drive. The flying capacitor multilevel inverter topology based on the classical and modified phase shift pulse width modulation (PSPWM, MPSPWM) techniques are applied in this paper to minimize harmonic distortion at the inverter output. Simulation results are presented for a 2-kW induction motor drive and the results obtained demonstrate reduced harmonics, improved transient responses and reference tracking performance of the voltage in the induction motor and consequently reduced torque ripplesPeer reviewe

The Breathing Mode in Extended Skyrme Model

We study an extended Skyrme model which includes fourth and sixth-order terms. We explore some static properties like the $\Delta$-nucleon mass splitting and investigate the Skyrmion breathing mode in the framework of the linear response theory. We find that the monopole response function has a pronounced peak located at $\sim$ 400 MeV, which we identify to the Roper resonance $N(1440)$. As compared to the standard one, the extended Skyrme model provides a more accurate description of baryon properties.Comment: 12 pages of plain Latex and 3 figures (available from the authors), preprint IPNO/TH 93-0