Improved Performance and Power Quality of Direct Torque Control of Asynchronous Motor by Using Intelligent Controllers

Abstract

Direct torque control of asynchronous motors has good dynamic performance of torque and flux. However, the use of hysteresis controllers leads to a variable switching frequency. This lack of control over frequency is the origin of torque and flux ripples. To overcome these problems, this article proposes modified fuzzy direct torque control for an induction motor. In addition, a three-phase pulse width modulation rectifier controlled by the fuzzy direct power control is used. This rectifier draws a sinusoidal current from the grid and operates with a power factor close to unity. The pulse width modulation rectifier feeds the inverter of the direct torque control, ensuring a speed control loop. The proposed direct torque control–direct power control method is investigated based on theoretical analysis, computer simulation, and experimental validation that provide acceptable results.