Modern improvement techniques of direct torque control for induction motor drives - a review
Résumé
The aim of this work is to search for better control and optimization of a photovoltaic (PV) water pumping system (PWPS) using the induction motor. A proposed method based on Fuzzy Logic Control (FLC) is introduced and investigated to improve the conventional Direct Torque Control (DTC). Variable step size Perturb and observe (P&O) is used to extract the maximum possible power from the PV panel. The validation of the control strategy is ensured by reducing the high torque, stator flux ripples and current harmonics in induction machine and increasing pumped water flow. Simulation results of the DTC based on FLC are compared with those of the conventional DTC using MATLAB/SIMULINK. The comparison results show the effectiveness of the FLC controller in terms of torque and flux ripples reduction, and daily pumped water.
Conventional direct torque control (DTC) is one of the excellent control strategies available to control the torque of the induction machine (IM). However, the low switching frequency of the DTC causes high ripples in the flux and torque that leads to an acoustic noise which degrades the control performances, especially at low speeds. Many direct torque control techniques were appeared to remedy these problems by focusing specifically on the torque and flux. In this paper, a state of the art review of various modern techniques for improving the performance of DTC control is presented. The objective is to make a critical analysis of these methods in terms of ripples reduction, tracking speed, switching loss, algorithm complexity and parameter sensitivity. Further, it is envisaged that the information presented in this review paper will be a valuable gathering of information for academic and industrial researchers.