Electrical Engneering Department

This paper considers the control problem for an underactuated quadrotor UAV system in presence of sensor faults. Dynamic modelling of quadrotor while taking into account various physical phenomena, which can influence the dynamics of a flying structure is presented. Subsequently, a new control strategy based on robust integral backstepping approach using sliding mode and taking into account the sensor faults is developed.
Lyapunov based stability analysis shows that the proposed control strategy design keep the stability of the closed loop dynamics of the quadrotor UAV even after the presence of sensor failures. Numerical simulation results are provided to show the good tracking performance of proposed control laws.

The theoretical sensitivity of conventional partial discharge detectors is compared with that obtained from ultra wideband (UWB) (up to 1 GHz) detection systems. The comparison indicates that for relatively lossfree distributed systems, such -a-s SFe insulated bus, the UWB system is up to two orders of magnitude more sensitive. UWB detection also embodies additional advantages such as facilitating the location of discharge sites and the rejection of external electrical noise. For discharge detection in plastic-insulated cables, true UWB detection is not practical because of frequency-dependent attenuation effects, although certain gains in sensitivity can be achieved with a detector bandwidth of up to 10 MHz.

In this paper, a time stepping 2D and 3D FEM is performed for modeling and analysis external rotor DFIG .The finite element method currently represents the state-of-the-art in the numerical magnetic field computation relating to electrical machines. FEM is a numerical method to solve the partial differential equations (PDE) that expresses the physical quantities of interest, in this case Maxwell’s equations. This will result in a more accurate result compared to analytical modeling, which can be regarded as a simplification of the PDE. FEM analysis is used for transient mode, magnetic field calculation, the magnetic flux density and vector potential of machine is obtained. In this model we including, non linear material characteristics, eddy current effect, torque-speed characteristics, ambient temperature effect and magnetic analysis are investigated using MAXWELL program. With this program, the components of the DFIG can be calculated with high accuracy.

The induction machine, because of its robustness and low-cost, is commonly used in the industry. Nevertheless, as every type of electrical machine, this machine suffers of some limitations. The most important one is the working temperature which is the dimensioning parameter for the definition of the nominal working point and the machine lifetime. Due to a strong demand concerning thermal monitoring methods appeared in the industry sector. In this context, the adding of temperature sensors is not acceptable and the studied methods tend to use sensorless approaches such as observators or parameters estimators like the extended Kalman Filter (EKF). Then the important criteria are reliability, computational cost ad real time implementation.

Permanent magnet synchronous generators (PMSGs) have a bright prospect in the small wind turbine (WT) applications; PMSGs compared to the conventional electrically excitated generators have many advantages, that’s why they have attracted many and a strong interest of research. In this paper, a comparative PMSG performance study's is presented, these performances is studied as a function of physical material like the type of permanent magnet (high, poor, average and linear), as a function of the environmental conditions as rotor speed, finally, as a function of the design and geometrical parameters (rotor length, number of poles, number of stator slots). These results are obtained by finite element method (FEM); this approach is a powerful and useful tool to study and design PMSGs, as represented in this paper.

In this paper we interested to the study the necessary of Facts to increase the transient stability on the presence of faults and the integration of new renewable source, like wind energy, these lasts make the electrical grid operate in a new conditions, the STATCOM is one of the important Facts element, It provides the desired reactive-power generation and absorption entirely by means of electronic processing of the voltage and current waveforms in a voltage source converter (VSC). This function is identical to the synchronous condenser with rotating mass. In present work we propose a transient stability improvement using STATCOM under faults, in the first time we study the transient stability with and without STATCOM for clearly his advantages. In the second time we know the relation between the reactive power injecting by a STATCOM and the critical clearing time, some simulation results are given, commented and discussed.

This paper deals with investigation on non purely sinusoidal input supply analysis of line-start PMM using finite element analysis (FEA), in the present times a greater awareness is generated by the problems of harmonic voltages and currents produced by non-linear loads like the power electronic converters. These combine with non-linear nature of PMM core and produce severe distortions in voltages and currents and increase the power loss, additional copper losses due to harmonic currents, increased core losses, electromagnetic interference with communication circuits, efficiency reduction, increased in motors temperature and torque oscillations. In addition to the operation of PMM on the sinusoidal supplies, the harmonic behavior becomes important as the size and rating of the PMM increases. Thus the study of harmonics is of great practical significance in the operation of PMM.

Permanent magnet Synchronous machines (PMSM) provide high efficiency, compact size, robustness, lightw eight, and low noise; these features qualify them as the best suitable machine for medical applications. With out forgetting its simple structure, high thrust, ease of maintenance, and controller feedback, make it possible to take the place of steam catapults in the future. This paper presents the synergetic control approach for PMSM. Synergetic control theory is purely analytical and is based on nonlinear models, provide asymptotic stability. This approach allows to reduce the chattering pheno menon. To verify the performance characteristics of this approach, we compare it with sliding mode. Simulation results are presented to show the effectiveness of the proposed control method.

—The objective of this paper is to develop an Artificial Neural Network (ANN) model to estimate simultaneously, parameters and state of a brushed DC machine. The proposed ANN estimator is novel in the sense that his estimates simultaneously temperature, speed and rotor resistance based only on the measurement of the voltage and current inputs. Many types of ANN estimators have been designed by a lot of researchers during the last two decades. Each type is designed for a specific application. The thermal behavior of the motor is very slow, which leads to large amounts of data sets. The standard ANN use often Multi-Layer Perceptron (MLP) with Levenberg-Marquardt Backpropagation (LMBP), among the limits of LMBP in the case of large number of data, so the use of MLP based on LMBP is no longer valid in our case. As solution, we propose the use of Cascade-Forward Neural Network (CFNN) based Bayesian Regulation backpropagation (BRBP). To test our estimator robustness a random white-Gaussian noise has been added to the sets. The proposed estimator is in our viewpoint accurate and robust.

Cet article présenté une etude comparative entre trois stratégies de la commande DTC à 6 sectors basée sur les réseaux de neurones artificiels de la machine asynchrone (1MW) alimentée par onduleur NPC de tension à sept niveaux. Cette commande est robuste et simple d'implémentation. La DTC-ANN à 6 secteurs avec une nouvelle table de commutation réduit considérablement les ondulations du couple et du flux. Mots Cles— Machine asynchrone; Commande DTC; Onduleur à sept niveaux; Réseaux de neurones; Table de commutation.

it is not my paper
Some companies in the motor and generator industry utilizing sintered NdFeB magnets have adopted pre-ageing heat treatment in order to improve the stability of the magnets. The parameters of this stabilization heat treatment are based mainly on assumptions rather than on any published research results. In this work, the effects of pre-ageing treatment on the time-dependent polarization losses of two different types of commercial sintered NdFeB magnets were studied. The material showing the squarer J(H) curve did not benefit from the pre-ageing treatment, since it seems to be stable under a certain critical temperature. In contrast, a stabilizing effect was observed in the material showing rounder J(H) curve. After the stabilization heat treatment, the polarization of the magnets was found to be at lower level, but unchanged over a certain period of time. The length of this period depends on the temperature and the duration of the pre-ageing treatment. In addition, our analysis reveals that the stabilization heat treatment performed in an open circuit condition does not stabilize the magnet uniformly.

it is not my paper
Renewable energy sources, especially wind turbine generators, are considered as important generation alternatives in electric power systems because they have no exhausted nature and not harmful environmental effects. Permanent magnet generator has a good prospect in small scale wind turbine application. Many types of generator concepts have been proposed and used, but most of the low speed application consist Permanent magnet generator. As compare to conventional electrically excited generators, PMG have many advantages, so it attracted towards interest of research. The purpose of this paper is to review Permanent magnet generator configuration, design methodology, design optimization, and analysis of permanent magnet generator. Different Machine configurations proposed in literature are also discussed for suitability to small scale wind turbine application.

it is not my paper
Dans cet article, nous allons procéder une comparaison des performances de deux structure de la commande directe du couple (DTC) de la machine asynchrone de forte puissance (1MW) alimentée par onduleur de tension à deux niveaux. La commande DTC neuronale (DTC-RNA), et la DTC basée sur le contrôleur PI-neuronale (PIN), les résultats de simulation sont présentés. Les ondulations du flux, et du couple seront évaluées puis comparées. L'objectif est déterminé la commande qui donne le meilleur résultat. ABSTRACT Comparative study between the neuronal DTC command and the DTC command based on the PI-neuronal controller of the asynchronous machine In this paper, we will compare the performances of two structures of the direct torque control (DTC) of the high power (1MW) asynchronous machine powered by two-level voltage inverters. The neuronal DTC control (DTC-RNA), and the PI-neuronal controller-based (PIN) DTC, simulation results are presented. The flux and torque ripples will be evaluated and then compared. The goal is determined the command that gives the best result.