Simulation Study of Two Torque Optimization Methods for Direct Torque-Controlled Induction Motors

Hani Albalawi,Sherif A Zaid,Yonis M Buswig

doi:10.3390/app9245547

Hani Albalawi, Sherif A Zaid + Show 1 more

Open Access

https://doi.org/10.3390/app9245547

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Abstract

The simplicity and excellent dynamic performance of Direct Torque Control (DTC) make Induction Motor (IM) drives attractive for many applications that require precise torque control. The traditional version of DTC uses hysteresis controllers. Unfortunately, the nature of these controllers prevents the optimization of the inverter voltage vectors inside the flux hysteresis band. The inverter voltage vector optimization can produce fast torque response of the IM drive. This research proposes two torque optimization methods for IM systems utilizing DTC. Analysis and Matlab simulations for the proposed optimization methods prove that the torque and, consequently, the speed responses, are greatly improved. The performances of the drive system controlled by the proposed optimization methods and the traditional DTC are compared. Conversely, the effects of the parameters on the proposed optimization methods are introduced. The proposed methods greatly improve the torque and speed dynamic performances against the traditional DTC technique. However, one of the proposed optimization methods is more sensitive to IM parameter variations than the other.

Highlights

There are many applications that require high-performance Induction Motor (IM) drives such as electric vehicles, mine winders, high-speed elevators, machine tools, and other more sophisticated machines
One of the proposed optimization methods is more sensitive to IM parameter variations than the other
The results prove that the torque optimization Method (2) does not depend on any parameters of the IM

Summary

Introduction

There are many applications that require high-performance Induction Motor (IM) drives such as electric vehicles, mine winders, high-speed elevators, machine tools, and other more sophisticated machines. These applications usually need speed–accuracy ≤0.5%, no less than 20:1 of wide-range speed control, and a speed transient response ≥50 rad/s [1,2,3,4]. Conventional DTC has the main disadvantage of having a wide band of inverter switching frequency, despite constant torque and flux [8]. The introduction of techniques using constant sampling helped to lead to the advancement of the DTC concept These techniques have replaced conventional analog hysteresis controllers

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