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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.


Azza H.B.,Unite de Recherche en Commande | Jemli M.,Unite de Recherche en Commande | Boussak M.,French National Center for Scientific Research | Gossa M.,Unite de Recherche en Commande
Simulation Modelling Practice and Theory | Year: 2011

The aim of this paper is to implement a sensorless Indirect Stator Field Oriented Control (ISFOC) of Single-Phase Induction Motor Drive (SPIMD) with stator resistance tuning. The proposed method for the estimation of speed is based only on measurement of stator currents. A very simple identification algorithm using d-axis stator current error for identifying the stator resistance is proposed. Experimental results for SPIMD are presented and analyzed by using a dSpace system with DS1104 control board based on the Digital Signal Processor (DSP) TMS320F240. Simulated results are compared with experimental results on a test 1.1 kW SPIM setup. The agreement between simulated and experimental results proves the validity of the proposed method. © 2010 Elsevier B.V. All rights reserved.


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.


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.


Khlaief A.,Unite de Recherche en Commande | Khlaief A.,CNRS Systems and Information Sciences Lab LSIS | Bendjedia M.,CNRS Systems and Information Sciences Lab LSIS | Boussak M.,CNRS Systems and Information Sciences Lab LSIS | Gossa M.,Unite de Recherche en Commande
IEEE Transactions on Power Electronics | Year: 2012

This paper aims to provide a high-performance sensorless control of interior permanent magnet synchronous motor (IPMSM) based on nonlinear position and speed observer. The proposed nonlinear observer is constructed using the flux linkage as new state variable without speed dependence. The nonlinear observer gives estimation of the rotor position using a trigonometric function and the speed estimation is obtained from estimated position using proportional-integral (PI) tracking controller. This observer is stable easy to implement and does not require a large computing time. At standstill, we used the voltage pulses method to detect the initial rotor position. Short voltage pulses are applied to the stator winding and the initial rotor position is estimated from the measured peak current. High-dynamic performance is obtained using the vector field-oriented control and the space vector pulsewidth modulation techniques. Experimental results with 1.1-kW IPMSM have validated the effectiveness of the proposed sensorless speed control using nonlinear observer. The experimental implementation is carried out on powerful dSpace DS1103 controller board based on the DSP TMS320F240. © 2006 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.


Moujahed M.,Unite de Recherche en Commande | Ben Azza H.,Unite de Recherche en Commande | Jemli M.,Unite de Recherche en Commande | Boussak M.,CNRS Systems and Information Sciences Lab LSIS
International Review of Electrical Engineering | Year: 2014

This paper proposes a Direct Torque Control (DTC) of a Permanent Magnet Synchronous Motor (PMSM) without mechanical speed and position sensors. These later are estimated by using the Extended Kalman Filter (EKF) only by measurement of the stator line voltages and currents. Moreover, DTC uses no current controller and no motor parameters other than the stator resistance, which yields a faster torque response and lower parameter dependence than with others motor control techniques. The Kalman filter is an observer for linear and nonlinear systems. Also, due to an angle modification scheme with error tracking, the Sensor-less drive system is robust to parameter variations. A load torque can also be estimated by using Luenberger Observer. A simulation model is developed in MATLAB/SIMULINK and is used to verify the basic operation (performance) of the Sensor-less DTC of PMSM. © 2014 Praise Worthy Prize S.r.l. - All rights reserved.


Khlaief A.,École Centrale Marseille | Boussak M.,École Centrale Marseille | Chaari A.,Unite de Recherche en Commande
2013 International Conference on Electrical Engineering and Software Applications, ICEESA 2013 | Year: 2013

Permanent Magnet Synchronous Motors (PMSM) are many used to high performance applications. Accurate faults detection can significantly improve system availability and reliability. This paper investigates the experimental implementation and detection of open phase faults in interior permanent magnet synchronous motor (IPMSM). The proposed method of open phase fault detection is based only on stator current measurement. The objective of this paper is to develop a new detection method for the open phase fault in IPMSM drives. The main idea consists in minimizing the number of sensors allowing the open stator phase fault of the system to study. This paper proposes the fault diagnosis for open-phase faults of IPMSM drives using a Discrete Fourier Transform phase. The current waveform patterns for various modes of open phase winding are investigated. Discrete Fourier Transform is used for the phases (φα, φβ) calculation. Experimental results show that the method is able to detect the open-phase faults in IPMSM drive. The experimental implementation is carried out on powerful dSpace DS1103 controller board based on the digital signal processor (DSP) TMS320F240. Experimental results obtained confirm the aforementioned study. © 2013 IEEE.


Trabelsi M.,École Centrale Marseille | Boussak M.,École 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.


Zaidi N.,Unite de Recherche en Commande | Azza H.B.,Unite de Recherche en Commande | Jemli M.,Unite de Recherche en Commande | Boussak M.,CNRS Systems and Information Sciences Lab LSIS | Chaari A.,Unite de Recherche en Commande
International Journal of Innovative Computing, Information and Control | Year: 2013

The accuracy knowledge of some state variables and motor parameters is required to the design of an efficient decoupled block or an exact linearization step dedicated for the classical Field Oriented Control (FOC) strategies. The aim of this paper is the elaboration of FOC strategy with high tracking performances and free of the on line adjustable decoupled block to drive a Single-Phase Induction Motor (SPIM). A full digital implementation of a novel speed vector control strategy based on Sliding Mode Control (SMC), to drive a SPIM, is presented. Adopting a very simple sliding surface design, and with the aim to generate a control signal free of chattering, three controllers qualified as Proportional Sliding Mode Controller (PSMC) are investigated. Adaptive sliding gain is conceived to improve the speed trajectory tracking performances under load disturbances. The asymptotically stability of the adaptive sliding mode control system is proved by means of the Lyapunov stability approach. An experimental platform around a DSP (dSPACE DS1104) is conceived to evaluate the real time implementation and the performances of the proposed speed vector control strategy. Simulation and experimental results highlight the effectiveness of the presented scheme and the performances of the adopted control law. © 2013 ICIC International.

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