94 publications from this institution
This paper describes an identification procedure by output error to estimate the parameters of an induction motor. This approach requires an optimisation algorithm. Two different strategies are considered: a genetic algorithm and a quasi-Newton algorithm. The last one requires the evaluation of the gradient and the Hessian in order to minimise a criterion in opposition to the first one. These two techniques have the advantage to be applied to linear and nonlinear models. They can take into account some constraints such as knowledge on electrical parameters. The experimental results prove the effectiveness of these two algorithms.
To identify the parameters of asynchronous machines, many methods are used. Many of them need a derivative during the optimization process. Unfortunately, a derivative function amplifies any noise due to numerical calculation or to measurement. As a consequence the search of the vector of parameters becomes difficult. Three minimization methods without derivatives are presented and applied to the identification of the parameters of induction motors. They allow finding both electrical and mechanical parameters from the analysis of the starting stator current and the corresponding voltage. Firstly, each method is described. Secondly, for a given machine with known parameters, numerical simulations allow to test the methods in terms of computer consuming time, of convergence and uniqueness of solution. The last part is devoted to the applications of the methods in order to identify the parameters of two asynchronous machines.
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In the present paper, the equivalence between the magnetic images method and the classical variable separation method is set up. These methods are separately applied to calculate the magnetic scalar potentials and the magnetic vector potentials in the air-gap of some cylindrical synchronous machines, excited by surface permanent magnets with radial and/or azimuthal magnetisation, and without polar pieces. The rotor and the stator are assumed slotless, and the whole electric machine non saturated. The expressions of the magnetic scalar potentials of each method are interpreted, and their equivalence is established. The Mayn purpose of this paper is then the demonstration that the magnetic images method is applicable for the study of simplified synchronous machines. The interest of the magnetic images use in comparison with the variable separation method is shown.
Experimental results on the magnetic saturation effects on the control of a small synchronous reluctance machine (600 W) are presented in this paper. A new model of the machine, including saturation effects and cross magnetization is first developed. An approach based on total and mutual inductances is followed instead of the traditional approach through magnetizing and leakage inductances. All of the electrical and mechanical parameters measurements required for the simulations are given. A rotor-oriented vector control of the synchronous reluctance machine is achieved with a digital-signal-processor (DSP) board (TMS320C31) and experimental results are presented. When the magnetic circuit is saturated, the simulation with the developed model shows good, accurate results when compared to the experimental ones.
Experimental results of the magnetic saturation effects on the control of a small reluctance synchronous machine (600 W) are presented in this paper. The modeling of the machine without saturation effects is first developed using the space vector theory and then, the electrical parameters measurement are given. A rotor-oriented vector control of the synchronous reluctance machine is achieved with a DSP board (TMS320C31) and experimental results are presented. When the magnetic circuit is unsaturated, the simulation shows a good accuracy of the results when they are compared to the experimental ones. Change differences appear with the saturation.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not.The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Calcul analytique du champ engendré par des aimants dans l'entrefer d'une machine à rotor dentéF. Sargos, A.
Experimental results on the magnetic saturation effects on the control of a small synchronous reluctance machine (600 W) are presented in this paper. A new model of the machine, including saturation effects and cross magnetization, is first developed. An approach based on total and mutual inductances is followed instead of the traditional approach via magnetizing and leakage inductances. All the electrical and mechanical parameters measurement required for the simulations are given. A rotor-oriented vector control of the synchronous reluctance machine is achieved with a DSP board (TMS320C31) and experimental results are presented. When the magnetic circuit is saturated, the simulation with the developed model shows a good accuracy of the results when they are compared to the experimental ones.
This paper deals with a comparison between different structures of double-star induction motors (DSIMs), controlled by space vector PWM. The modelling of the DSIM is made using an arbitrary shift angle between the two three-phase windings. A new transformation matrix is proposed to develop a suitable dynamic model and to elaborate the space vector PWM control strategy for different values of this shift angle. Simulation results are presented and compared. The effects of the shift angle on the dynamic performances, and on the complexity of calculating the PWM control strategy, are pointed out.
For particular applications, the design of systems composed of several superconducting coils needs good accuracy in calculations. Using analytical methods involving elliptic integrals, themselves calculated using the AGM method, all electromagnetic values can be evaluated with a good precision. An application to a superconducting toroidal core illustrates this study.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
An analytical representation of the potential created by charged sectors of a ring has been investigated. The surface charge density of the ring is supposed to be constant along a radius, assuming that a Fourier series development allows simplification into a linear superposition of sinusoidal surface densities. In addition to the obvious electrostatic devices, this approach also applies-because of the similarity of the magnetic equations-to permanent magnets with a uniform magnetization. Laplace's equation is solved by means of separation of variables. A Hankel transform, followed by a numerical integration of a Laplace transform, leads to the identification of the coefficients. Most generally, this integration involves elliptic functions which allow a fast and precise numerical treatment. At any point in space, the potentials are computed with the same simplicity and nearly the same accuracy. The proposed method introduces no systematic error and requires only a small memory-size desk computer. It is also much faster than purely numerical methods such as FEM or FDM; any change in the geometrical dimensions can also be achieved without previous reconditioning. The results of this method compare favorably with those already obtained for homopolar distributions and also with previous experiments on an eight-pole-pair distribution of magnets.
This study demonstrates the conversion of agricultural and industrial waste into construction materials by developing ultra-high-performance concrete using cold-bonded sesame ash and waste glass aggregates. The primary focus of this study was sustainability and waste valorization in self-curing concrete systems. This study focuses on many aspects of producing cementless concrete with superior short- and long-term properties, incorporating an innovative artificial aggregate premanufactured using sesame ash and waste glass. Prepacking technology of casting was used. A self-curing additive is used to reduce the energy required for curing. In cold-bonded aggregates (CBAs), the aggregate content ranged from 10 to 50% of the total sand volume. Polyethylene glycol was used as an internal curing agent to evaluate the mechanical properties of the concrete, including the compressive strength and tensile strength at different ages. The durability characteristics of the concrete were also analyzed in terms of its resistance to sulfates, chloride ion penetration, and performance at elevated temperatures of 300 and 600 °C. Microscopic analyses were conducted by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). The results showed a significant improvement in the mechanical and durability performance, especially at 30%, which resulted in the highest compressive strength of 147.2 MPa at 90 days. This is an 11.93% increase compared with that of the reference mix. The tensile strength was also improved by 14.5% at the same replacement ratio. The mix containing 30% manufactured aggregate demonstrated the best thermal resistance, retaining the highest percentage of residual strength at both 300 °C and 600 °C, as well as superior sulfate impact resistance, with a strength reduction factor of 39.5%. When the replacement ratio was increased to 50%, the chloride penetration resistance improved significantly by 41% compared with that of the reference mix. FTIR, TGA, and DSC analyses also demonstrated enhanced silicate polymerization and increased carbonate formation, contributing to the improved chemical stability and density of the concrete matrix.
Most of rotor related faults in three-phase induction motors are due to broken rotor bars and end-ring defects. Nowadays Inductions motors are more frequently used with inverters which make the diagnosis process more complicated. Furthermore, some manufacturers of induction machines mount converters (i.e. rectifier and inverter) directly onto the machine, which makes the stator current unattainable for diagnosis. In order to overcome these drawbacks, the authors propose to analyze new motor fault signatures in the supply line current of the inverter. Experimental and simulation results show a total agreement and confirm the effectiveness of the present study.
