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Lazhari Nezli and Mohand Mahmoudi

Vector Control with Optimal Torque of a Salient-Pole Double Star Synchronous Machine Supplied by Three-Level Inverters

This work relates to the study of the vector control of the salient-pole double star synchronous machine drive (DSSM) fed by three-level inverters which are controlled by PWM hysteresis strategy. Indeed, it is a question of carrying out a decoupling between rotor flux and electromagnetic torque, by introducing a vector control with an optimal torque working and by imposing constant flux regime. Furthermore, to ensure a decoupled dynamic behavior of the machine as in the case of a DC machine, a regulation of the rotor current has been introduced through a chopper operating at 5 kHz chopping frequency, feeding the excitation circuit. The obtained results are very satisfactory and reveal the effectiveness of the proposed approach.

Open access

Djamel Boudana, Lazhari Nezli, Abdelhalim Tlemçani, Mohand Mahmoudi and Mohamed Tadjine

Robust DTC Based on Adaptive Fuzzy Control of Double Star Synchronous Machine Drive with Fixed Switching Frequency

The double star synchronous machine (DSSM) is widely used for high power traction drives. It possesses several advantages over the conventional three phase machine. To reduce the torque ripple the DSSM are supplied with source voltage inverter (VSI). The model of the system DSSM-VSI is high order, multivariable and nonlinear. Further, big harmonic currents are generated. The aim of this paper is to develop a new direct torque adaptive fuzzy logic control in order to control DSSM and minimize the harmonics currents. Simulations results are given to show the effectiveness of our approach.

Open access

Mohamed Mounir Rezaoui, Lazhari Nezli and Mohand Oulhadj Mahmoudi

Abstract

In this paper, we study an analytic technique to control matrix converter for a four-quadrant five-phase induction machine drive with use PWM five intervals modulation strategy. The multiphase induction machine is feeding by a matrix converter using a three-phase network. Special emphasis is given to the sinusoidal five phase voltage in the output and five phase voltage input current modulation. Simulation results are presented.

Open access

Khelifa Khelifi Otmane, Nordine Bali and Lazhari Nezli

Abstract

An off-line methodology was proposed for enhancing the robustness of an initial Generalized Predictive Control (GPC) by convex optimization of the Youla parameter. However, this procedure of robustification is restricted with the case of the systems affected only by unstructured uncertainties. This paper proposes an extension of this method to the systems subjected to both unstructured and structured polytopic uncertainties. The main idea consists in adding supplementary constraints to the optimization problem which validates the Lipatov stability condition at each vertex of the polytope. These polytopic uncertainties impose a set of non convex quadratic constraints. The globally optimal solution is found by means of the GloptiPoly3 software. Therefore, this robustification provides stability robustness towards unstructured uncertainties for the nominal system, while guaranteeing stability properties over a specified polytopic domain of uncertainties. Finally, an illustrative example is given

Open access

Khelifi Otmane Khelifa, Bali Noureddine and Nezli Lazhari

Abstract

An off-line methodology has been developed to improve the robustness of an initial generalized predictive control (GPC) through convex optimization of the Youla parameter. However, this method is restricted with the case of the systems affected only by unstructured uncertainties. This paper proposes an extension of this method to the systems subjected to both unstructured and polytopic uncertainties. The basic idea consists in adding supplementary constraints to the optimization problem which validates the Lipatov stability condition at each vertex of the polytope. These polytopic uncertainties impose a non convex quadratically constrained quadratic programming (QCQP) problem. Based on semidefinite programming (SDP), this problem is relaxed and solved. Therefore, the robustification provides stability robustness towards unstructured uncertainties for the nominal system, while guaranteeing stability properties over a specified polytopic domain of uncertainties. Finally, we present a numerical example to demonstrate the proposed method.

Open access

Mohamed Mounir Rezaoui, Lazhari Nezli, Mohand Oulhadj Mahmoudi, Abdollah Kouzou and Haitham Abu Rub

Abstract

In this paper, the application of the proposed control strategy PWM three intervals with 3×5 matrix converter is presented and analyzed. This control strategy is developed for the control of the multi-phases matrix converter, where the main aim is to ensure the waveform quality of the output voltages and the input currents based on the THD evaluation. Simulation results and real time implementation on dSpace 1103 of 3×5 matrix converter under R-L load are presented for the validation of the proposed control strategy and to clarify the main related advantages.