This paper is intended to study and compare the operation of two methods for estimating the position/ speed of the permanent magnet synchronous motor (PMSM) under sliding mode control. The first method is a model reference adaptive system (MRAS). The second method based on sliding mode observer (SMO). The stability condition of Sliding Mode Observer was verified using the Lyapunov method to make sure that the observer is stable in converging to the sliding mode plane. In this paper the performances of the proposed two algorithms are analyzed using SIMULINK/MATLAB. The simulations results are presented to verify the proposed sensorless control algorithms and can resolve the problem of load disturbance effects by simulations which verify that the two closed-loop control system is robust with respect to torque disturbance rejection. Keyword:Model reference adaptive MRAS PMSM Sensorless speed control Sliding mode control SMC Sliding mode observer SMO Copyright © 2017 Institute of Advanced Engineering and Science.All rights reserved. Corresponding Author:LARBI M'hamed, L2GEGI-Labotatory, University Ibn-Khaldoun of Tiaret, Algeria, 14000. Email: larbi_mh@yahoo.fr INTRODUCTIONThe permanent magnet synchronous motors attract the industrial world attention thanks to their superior advantages, for instance their higher efficiency, low inertia, high torque to current ratio. As an important application of PMSM, the motion control requires not only the accurate knowledge of rotor position for field orientation but also the information of rotor speed for closed-loop control; thus, position transducers such as optical encoders and resolvers are needed to be installed on the shaft [1], [2]. However, these sensors are expensive and very sensitive to environmental constraints such as vibration and temperature [3]. In order to overcome these problems, instead of using position sensors, a sensorless control method has been developed for control of the motor [4]. The basic principle of sensorless control is to deduce the rotor speed and position using various information and means, including direct calculation, parameter identification, condition estimation, indirect measuring and so on. The stator currents and voltages are generally used to calculate the information of speed and rotor position [5].The sliding mode control has been used to improve the robustness of the controller. during the sliding mode, this controller is insensitive to parameter variations and disturbances [6]. Therefore, many approaches for speed estimation have been investigated in the literature [7]-[8].This paper presents two methods for estimating the position and speed of a permanent magnet synchronous motor (PMSM) drive. The first method is Model Reference Adaptive System. It makes use of the redundancy of two machine models of different structures that estimate the same state variable (rotor speed) of different set of input variables [9]. The estimator that does not involve the quantity to be estimated is chosen as the reference model, and the other estima...

This paper presents an experimental study of the RST method applied to control the speed of a Permanent Magnets Synchronous Motor (PMSM) supplied with a vectorial PWM (Pulse Width Modulation) inverter. The RST is used together with a predictive state observer in order to estimate the load torque. The experimental results prove that the presence of this observer allows a better control of the actuator behavior while guaranteeing robustness characterized by a good insensitivity with respect the parametric variations. Keywords -Control of Drive, Permanent MagnetSynchronous Motor (PMSM), Robust control, Robustness, DSP. I. Nomenclature V sd , V sq Stator winding d, q axis voltage respectively i sd, i sq Stator winding d, q axis current respectively i sd * , i sd * Reference stator current winding d, q axis current respectively ω The electric speed of the rotor * ω Reference rotor speed ω Estimated rotor speed θ Rotor position Φ f Permanent flux R s Stator phase resistance L sd , L sq T he stator inductances of the axis d and the axis q J inertia of the turning parts f c Viscous friction coefficient p Poles pairs number. r C Load torque r Ĉ Estimated load torque s Laplace operatorII. Introduction Permanent magnet synchronous motors (PMSMs) are of great interest especially for industrial applications in lowmedium power range, since it has superior features such as compact size, high torque/weight ratio, high torque/inertia ratio and absence of rotor losses [1-2]. However, the performance of the PMSM is very sensitive to external load disturbances and parameter variations in the plant. To overcome these problems several control strategies such RST controller associated to the load observer, have been proposed for speed control of a PMSM.The vector control method, known as a cascade type regulation, was widely used [3-4-12] and [16]. The advantages of this method are given in [7][8][9][10][11][12][13]. For this, two loops are adopted in order to obtain the desired outputs. Initially, we release the internal loop which ensures the current control. Then, the synthesis of an external loop allows the speed control [4][5][6][7][8][9][10][11].However, the presence of external disturbances and parametric variations in the motor, limit the dynamic performances of the traditional vector control method, to use conventional regulators PID. In addition, a theoretical question is asked: is it possible to develop a simple control strategy which exploits the advantages of the vector control method of the PMSM and overcoming the problems involved in the limitations of the conventional approaches.Actually, the concept of the RST is very important in the analysis of the transient stability in fact that it is able to improve the performances obtained with traditional PID regulator, decoupling the axes (dq) while considering the presence of the parametric variations [16].The main purpose of this paper is to conceive an empirical environment containing a digital computer (Dspace 1104) allowing the implementation of the RST control. This cont...

Introduction. To attain high efficiency and reliability in the field of clean energy conversion, power electronics play a significant role in a wide range of applications. More effort is being made to increase the dependability of power electronics systems. Purpose. In order to avoid any undesirable effects or disturbances that negatively affect the continuity of service in the field of energy production, this research provides a fault detection technique for insulated-gate bipolar transistor open-circuit faults in a three-level diode-clamped inverter of a wind energy conversion system predicated on a doubly-fed induction generator. The novelty of the suggested work ensures the regulation of power exchanged between the system and the grid without faults, advanced intelligence approaches based on a multilayer artificial neural network are used to discover and locate this type of defect; the database is based on the module and phase angle of three-phase stator currents of induction generators. The proposed methods are designed for the detection of one or two open-circuit faults in the power switches of the side converter of a doubly-fed induction generator in a wind energy conversion system. Methods. In the proposed detection method, only the three-phase stator current module and phase angle are used to identify the faulty switch. The primary goal of this fault diagnosis system is to effectively detect and locate failures in one or even more neutral point clamped inverter switches. Practical value. The performance of the controllers is evaluated under different operating conditions of the power system, and the reliability, feasibility, and effectiveness of the proposed fault detection have been verified under various open-switch fault conditions. The diagnostic approach is also robust to transient conditions posed by changes in load and speed. The proposed diagnostic technique's performance and effectiveness are both proven by simulation in the SimPower /Simulink® MATLAB environment.

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<p>To improve the performance of permanent-magnet synchronous motor (PMSM) drives powered by the voltage inverter with PWM control, a sensorless control scheme based on a Model Reference Adaptive System (MRAS) a fuzzy logic controller (FLC) based in with fuzzy supervisor structure. The major drawbacks of the conventional MRAS, namely chattering phenomena, high-order harmonics andexternal noise, are discussed. These drawbacks affect the estimated speed accuracy of the MRAS and reduce the control reliability of the system. To eliminate these drawbacks, an FLC is designed and integrated into the MRAS to adjust the observer gain to reduce the chattering in closed loop speed and closed loop current/torque. Comparative simulations using the proposed Fuzzy-MRAS and the conventional MRAS are performed to validate the effectiveness of the proposed FLC structure. Performance simulations of the overall proposed Fuzzy-MRAS based sensorless control scheme are performed to verify the robustness and control reliability of the system. The results show that the proposed Fuzzy MRAS has satisfactory performances with reduction of total harmonic distortion generated in the phase currents.</p>