Comparative Analysis of the Characteristics of Asynchro- nous Drives with Vector Control and Direct Torque Control

Abstract

   Active development of electric drive theory in recent decades has led to the emergence of various methods for asynchronous three-phase motors control, promoted by leading drive development companies, the competition between which inevitably gives rise to false preconceptions about the real capabilities and characteristics of these methods. Additionally, literary sources often bypass positional drives, focusing on speed control, and the same can be said about the preference for synchronous drives over asynchronous ones. This study solves the problem of a comprehensive comparison of the characteristics of classical vector control based drives and direct torque control schemes at the levels of theoretical description and computer simulation. To solve this problem mathematical descriptions and functional diagrams of asynchronous motors with indicated control systems are given and analyzed and models of considered systems are developed in the Simulink environment of the Matlab program, considering flexibility of mechanical transmission and various resistance moments and allowing to form a quantitative assessment of considered characteristics. The results of numerical modeling are presented on example of a specific induction motor with a squirrel-cage rotor DMChTs 80-2-8OM2 for each system variant in several operating modes, which are of interest for various options of such drives practical application and identifying considered control methods individual features. Advantages and disadvantages formulated as a result, as well as recommendations for the use of the compared drive systems, are quite universal and can be used in design of various drives with both asynchro-nous and synchronous motors.