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Khlaief A.,CNRS Systems and Information Sciences Lab LSIS | Boussak M.,CNRS Systems and Information Sciences Lab LSIS | Chaari A.,Unite de Recherche en Commande
Electric Power Systems Research | Year: 2014

In this paper, model reference adaptive system (MRAS) technique has been used for speed estimation in sensorless speed control of interior permanent magnet synchronous motor (IPMSM) with space vector pulse width modulation (SVPWM). Most of the current researches studying the MRAS technique are based on non-saliency PMSM model and ignore the difference between d- and q-axes inductances. This paper studies a novel MRAS observer, considering the saliency of PMSM. However, this sensorless speed control shows great sensitivity to stator resistance and system noise, particularly, during low-speed operation. A novel stator resistance estimator is incorporated into the sensorless drive to compensate the effects of stator resistance variation. A stability-analysis method of this novel MRAS estimator is shown. Stable and efficient estimation of rotor speed at low region will be guaranteed by simultaneous identification of IPMSM. The stability of proposed stator resistance estimator is checked through Popov's hyperstability theorem. The proposed observer is experimentally tested using a 1.1-kW motor drive; stable operation at very low speeds under different loading conditions is demonstrated. The real time implementation concept on the digital signal processor (DSP) board of the VFOC design and SVPWM inverter technique are illustrated. Results show that the proposed MRAS technique can satisfactorily estimate the position and speed of PMSM with saliency. © 2013 Elsevier B.V. All rights reserved.


Ben Hmida F.,Unite de Recherche en Commande
Journal of Quality in Maintenance Engineering | Year: 2010

Purpose - The purpose of this paper is to study the evolution of a system stationary availability and determine the optimal preventive maintenance period, which maximises it in a context where preventive and corrective maintenance actions are imperfect and have non-negligible durations. Design/methodology/ approach - The quasi-renewal process approach and a (p, q) rule are respectively used to model corrective and preventive maintenance. Considering the durations of the preventive and corrective maintenance actions as well as their respective efficiency extents, a mathematical model and a numerical algorithm are developed in order to compute the system stationary availability. Findings - It has been proven that for any given situation regarding the system, the repair and preventive maintenance efficiency extents, and the downtime durations for preventive and corrective maintenance, there is necessarily a finite optimal period T* of preventive maintenance which maximises the system stationary availability. A sufficient condition for the uniqueness of the optimal solution has also been derived. Numerical examples illustrated how preventive and corrective maintenance efficiency extents affect simultaneously the system optimal availability. Practical implications - The study considers a general industrial framework where preventive and corrective maintenance actions are imperfect. In fact, neither the best-qualified technicians nor the most suitable tools or spare parts are found to carry out maintenance actions. In such a context for a large variety of technical systems, when implementing preventive maintenance policies one should take into account the efficiency extents of maintenance actions as well as their durations in order to evaluate and optimise the system availability. The paper provides maintenance managers with a decision model allowing not only the computation and optimisation of system availability, but also the investigation of how preventive and corrective maintenance efficiency extents affect simultaneously the system optimal availability. The proposed model also allows one to find to what extent corrective actions ineffectiveness should be tolerated without having an important availability loss. Originality/value - The paper proposes a modified formulation of the quasi-renewal process taking into account the non-negligible duration of corrective maintenance actions and periodic preventive maintenance. A new numerical algorithm is also developed in this context to compute the quasi-renewal function that it is impossible to find in closed form. This allowed the computation and optimisation of system stationary availability. © Emerald Group Publishing Limited.


Trabelsi M.,Ecole Centrale Marseille | Boussak M.,Ecole Centrale Marseille | Chaari A.,Unite de Recherche en Commande
Proceedings - 2012 20th International Conference on Electrical Machines, ICEM 2012 | Year: 2012

This paper deals with a new approach for single and multiple open-circuit faults diagnoses in voltage source inverter (VSI) fed induction motors. The diagnosis procedure is based on the knowledge of the outputs inverter currents distribution in α-β frame combined with additional diagnosis variables which use their mean values. In a first step, twenty seven patterns built with output inverter currents in α-β axis are used to detect the faulty legs. Six of them are dedicated to the single-fault modes and the others to the multiple open-switch modes. A second step is achieved by normalizing the average line currents. The use of normalized current-average values allows not only the fast identification of the single fault but also makes it possible to distinguish several multiple-fault cases having the same signatures in α-β frame. The simulation results of fault detection and identification method are included to prove that the proposal leads to good results. © 2012 IEEE.


Trabelsi M.,CNRS Systems and Information Sciences Lab LSIS | Jouili M.,Research Unity of Automatic Control | Boussak M.,CNRS Systems and Information Sciences Lab LSIS | Koubaa Y.,Research Unity of Automatic Control | Gossa M.,Unite de Recherche en Commande
Proceedings - ISIE 2011: 2011 IEEE International Symposium on Industrial Electronics | Year: 2011

The aim of the present paper is double; the first is to implement a sensorless Indirect Stator Field Oriented Control (ISFOC) of three phase induction motor drive based on the Luenberger Observer (LO). The second is to study the robustness and the limitations of the proposed sensorless vector control technique under abnormal operations of the electric drive. The proposed sensorless strategy is based on an algorithm permitting a better simultaneous estimation of the rotor speed and the flux linkage including an adaptive mechanism based on the lyaponov theory. To study the reliability, the robustness and the limitations of the sensorless technique to abnormal operations, some experimental tests have been performed under several cases: single open switch damage in a leg, multiple faults involving two transistors belonging to the same inverter leg. For healthy and faulty operation mode, an experimental setup based on a 3kW squirrel-cage induction motor has been used. © 2011 IEEE.


Ben Azza D.H.,Unite de Recherche en Commande | Jemli M.,Unite de Recherche en Commande | Boussak M.,CNRS Systems and Information Sciences Lab LSIS | Gossa M.,Unite de Recherche en Commande
Iranian Journal of Science and Technology, Transaction B: Engineering | Year: 2011

This paper presents a new technique based on model reference adaptive system (MRAS) observer for sensorless speed control of Two-Phase Induction Motor (TPIM). The MRAS identification is performed by means of comparison of stator fluxes obtained from both stator and rotor equations with stator voltage and current measurements. Simulation and experimental results for a 1.1 kW TPIM set-up are presented and analysed using a dSpace system with a DS1104 controller board based on digital signal processor (DSP) TMS320F240. Simulation and experimental results at nominal, low and zero speeds confirm the effectiveness of the proposed sensorless speed controlled TPIM drive. © Shiraz University.

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