S. Mekhtoub

Complex finite element analysis of a solid rotor induction motor

A method for predicting the steady state performance of a solid rotor induction motor using coupled non-linear complex finite elements is described. The principle of the model is to consider two starting times, /spl omega/ in the stator region and s/spl omega/ in the rotor region. The coupling between the rotor and the stator is achieved by two means using Lagrange multipliers at a suitable air-gap interface. A comparison between the experimental and the computed characteristics of a solid rotor induction motor is performed with interesting results.

Performance optimization of synchronous reluctance machines with two rotor structures

The subject of this article is to optimize the design and compare the performances of synchronous reluctance machines with salient pole rotor and multi-flux barrier rotor. The optimization procedure, which focuses on the maximization of the machines torque to Ampere ratio, is based on a cyclic algorithm coupled with the magnetostatic finite-element field solutions. The optimization results regarding the two types of machines which provide the optimized rotor geometrical dimensions and the influence of the current angle are discussed.

Dynamics separation of induction machine models using gerschgorin's circles and singular perturbations

The authors present a development of reduced order models of the induction machine. The reduction is based on the application of Cerschgorin¿s circles to separate the different dynamics. The siagular perturbation technique for determining the reduced models is applied. These twostages require well specified state matrix (dominant state matrix). Such matrix form is obtained by some algebraic transformations on the fundamental state matrix.

Analysis of self-excited induction generator feeding DC loads for low-cost renewable energy applications

The present paper deals with a variable-speed low-cost wind power generator. The proposed generating apparatus consists of a squirrel-cage self-excited induction generator, a controlled AC/DC converter, and a closed-loop control system. The dynamic flux model of the self-excited induction generator used in the wind power-generator is presented. This model, which accounts for magnetic saturation, is validated by experimental results. Performance of the proposed wind power generator over broad operating ranges of load and speed is discussed. Simulation of variable speed operation of the generator through an artificially generated wind speed profile is illustrated. Finally, a harmonic distortion analysis of the measured voltage and current waveforms is performed and presented.

Analysis of transient currents of the connected self- excited induction generator following disturbance on the system supply

In this paper, the analysis of self excited induction generator (SEIG) connected to utility grid is studied. We simulated the reconnection of the SIEG to the utility grid after a short perturbation. A mathematical model of the induction generator using Parks model, where taking account the saturation of the magnetizing flux is developed. The experimental results of transient currents are approached by simulation, because the initial conditions are not the same ones in practice.

Sliding mode control and flux observer for a singularly perturbed model of an induction machine

The authors present a method based on the singular perturbation approach using the observers of sliding mode type for the flux estimation of an induction machine. The development of command law is based on the use of separation of fast and slow modes. The decomposition considerably simplify the control of an induction machine by the sliding mode techniques.

MIMO and MISO systems applied to an induction machine parameter identification

This paper presents MIMO and MISO systems applied to an induction machine parameter identification. The aim of this work is the determination of all the transfer functions of the inductions machine. The obtained parameters from MIMO and MISO systems are compared and tested in the simulation of dynamic performances.

Dynamic behavior of doubly fed induction generator during network voltage dips

The doubly fed induction generator (DFIG) is one of the mostly used options in variable-speed wind power generation. The present paper deals with the transient behavior of the DFIG during network voltage dips. The dynamic model used for the transient analysis of the DFIG during network disturbances is presented. Vector control strategy is used to ensure independent control of the active and reactive powers. In order to illustrate the behavior of the DFIG during network disturbances, two symmetrical voltage dips are applied the DFIG stator terminals. These voltage dips are both selected within the limits set by the grid codes considered in the present paper. Simulation results showing large transient stator and rotor currents are presented and discussed. Finally, the mostly used technique to ensure a low voltage ride-through capability for the DFIG and to minimize the effects of grid disturbances on the doubly fed induction generator is reviewed.

Low-Cost Wind Generator for Supplying Isolated DC loads

The present paper deals with a low-cost wind power generator. The proposed generator is very suitable and cost-effective for supplying isolated DC loads in remote areas where extension of grid is economically not feasible. The dynamic flux model of the self-excited induction generator used in the wind power-generator is given. This model, known to account for magnetic saturation is validated by experimental results. Performance of the generator under variable wind speed and/or variable load is discussed.

Application of Butterworth filter for parameter identification of an induction machine

The authors present the application of Butterworth filter for parameter identification of an induction machine. MlMO (multi-inputs/multi-outputs), SISO (Single-input/Single-output) and MISO (multi-input/single output) continuous model structures were undertaken by using the recursive least square algorithms. The identification of the induction machine parameters is carried out from the experimental standstill tests where an electric request without danger to the windings, is supplied by a DC-chopper, giving a capacity of persistent excitation which has for effect to generate a signal rich with information.