Grzegorz Tarchala

Original article: Sliding-mode direct torque control and sliding-mode observer with a magnetizing reactance estimator for the field-weakening of the induction motor drive

The paper deals with the sliding-mode control and the sliding-mode speed observer for the induction motor drive. The main interest of the paper is high speed operation, during the field-weakening, where the machine magnetizing characteristic is of great importance. Therefore the magnetizing reactance estimator, based on the magnetizing curve identification is used. The sliding mode technique is applied to design the direct control of the induction motor torque. A unified designing approach for control as well for the state space variables estimation is shown. Simulation and experimental results are shown to illustrate described problems.

Influence of the sign function approximation form on performance of the sliding-mode speed observer for induction motor drive

The paper deals with the speed oscillation reduction methods for the Sliding Mode Observers (SMOs) of the induction motor (IM). The oscillations introduced by the chattering phenomenon can be reduced using the sign function continuous approximation and simple adaptation method. In this method the observer gain is adapted linearly with reference or estimated speed value. Simulation and experimental test results, obtained in a DSP-based control system, are shown to illustrate presented issues.

Performance analysis of the sliding‐mode speed observer with magnetizing reactance estimation for the sensorless induction motor drive

Purpose – The purpose of this paper is to obtain an accurate and robust estimation method of the rotor flux and speed for the sensorless induction motor (IM) drive with magnetizing reactance variations.Design/methodology/approach – The sensorless IM drive with sliding mode flux and speed observer (SMO) is presented. Proposed estimation algorithm is extended with the additional magnetizing reactance estimator based on the magnetizing characteristic of the IM. The dynamical and steady‐state properties of the drive system in the low‐speed and in the field‐weakening regions are tested. The simulation results are verified by experimental tests, over the wide range of motor speed and drive parameter changes.Findings – It is shown that the sensorless induction motor drive can work stable in wide speed range using the Sliding‐Mode Observer with additional magnetizing reactance estimator.Research limitations/implications – The investigation looked mainly at the speed estimation methodology with additional motor pa...

Analysis of the chosen speed and flux estimators for sensorless induction motor drive

In the paper chosen rotor flux and speed estimation methods for the speed sensorless induction motor drive are presented. Speed estimators based on: the sliding mode theory (SMO), model reference adaptive systems (MRAS) technique and two chosen concepts based directly on the rotor slip frequency calculation are discussed and compared. Stator flux and speed estimators sensitivity to the motor parameter uncertainties is investigated. Simulation and experimental results of the sensorless DTC-SVM without speed control loop are presented. The low speed region and the dynamic properties of the IM drive with electromagnetic torque and stator flux feedbacks are tested.

Integral Sliding Mode Direct Torque Control of the induction motor drives

The purpose of this paper is to present simple and robust Sliding Mode Direct Torque Control method of induction motor. This control method ensures perfect torque response as well as stabilizing amplitude of stator or rotor flux. Chattering of the torque and flux is reduced using a simple sign function continuous approximation form. The switching function is extended with an integral part to eliminate the steady-state error.

Stator fault monitoring based on internal signals of vector controlled induction motor drives

This paper deals with the stator winding faults monitoring in the vector controlled induction motor drives. Two control methods were taken for analysis, namely the direct field oriented control - DFOC and the direct torque control - DTC. In both control structures the induction motor is supplied form two-level voltage inverter with space vector modulation (SVM). In order to detect the early stage of the stator winding inter-turn short-circuits, the analysis of characteristic components of internal control signals of the DFOC and DTC-SVM structures is used for diagnostic purposes. Experimental results obtained from a specially prepared induction motor working under vector control are presented.

Electrical faults diagnosis in the induction motor drive under the direct field oriented control

This paper deals with the diagnosis of the electrical faults of induction motor operating under the direct field-oriented control. Two different faults are taken into account: stator winding inter-turn short circuit and voltage source inverter transistor damage. The fault diagnostic algorithms are described. Performance of both algorithms is validated in presence of the different kind of damages. The presented methods are examined using the experimental setup with specially prepared induction motor and voltage source inverter.

Stator Faults Monitoring and Detection in Vector Controlled Induction Motor Drives—Comparative Study

This chapter deals with the stator winding faults detection in the induction motor drives working in the closed speed control loops, with the direct field oriented control—DFOC or with the direct torque control—DTC. In order to detect the early stage of stator winding inter-turn short-circuits, the analysis of characteristic components of the stator currents spectra, as well as the control signals of the DFOC structure, are used for diagnostic purposes. Experimental results obtained from a specially prepared induction motor working under vector control are presented.

Sliding Mode Speed and Position Control of Induction Motor Drive in Cascade Connection

This chapter deals with sliding mode application in control of an induction motor (IM) torque, speed, and position. Classical, direct approaches to control mentioned variables are described. Their drawbacks are presented and analyzed. Direct control structures are then compared with the proposed cascade sliding mode control structures. These structures allow to control all of the IM variables effectively, simultaneously ensuring supervision of all remaining variables. All of the analyzed structures are illustrated with block diagrams, as well as with simulation and experimental test results.

Application of a time-varying switching line in the cascade sliding-mode speed control of the induction motor drive

This paper deals with the sliding mode application in the control of the induction motor speed. The equivalent control method, in which the control signal consists of two parts: continuous and discontinuous is used. In order to ensure identical dynamics of the speed transients and system robustness during the switching line reaching phase, regardless of the external and parametric disturbances, the time-varying switching line is introduced.