Variable Speed AC Drives: The Past and Current Status

Authors:

C.M. Bhatia (Indian Institute of Technology, Delhi)

Sanjana Malhotra (Manav Rachna College of Engineering, Faridabad)

M.K. Soni (Manav Rachna International University, Faridabad)

Keywords: Variable Speed Drives; Pulse Width Modulation; Squirrel-Cage Induction Motor; Variable Frequency Operation; Inverters; Knowledge Based Protection; Power Semiconductor Devices; Intelligent Drives.

Abstract:

This paper presents a review of the state-of-the-art in Variable Speed Drive (VSD), through Power Electronics application and control. The major development trends even in the past had dominance of AC drives in a variety of applications, with the squirrel-cage and wound rotor induction motors as the preferred machine in most cases [1-4, 28]. Particularly striking has been the rapid ascendance of Power Electronics [5-12] and Pulse Width Modulation (PWM) technique in conjunction with Power Semiconductor Devices (PSDs) as the predominant switches [13-25,28] in industrial applications and control, ranging from fractional kilowatts to several I megawatts. Recent developments in Pulse Width Modulation (PWM) technique and functional control of PWM drives [17,26,27,31-33,35-38,40-55,58-67,70- 76,78,100], their user interface, menu driven interface and programmability have become very predominant [29,34,39,70,109,110]. The protection schemes contributing strongly towards knowledge based and intelligent drive control [77,85-89,92-99,101-102,105-109] have also been highlighted. The review paper thus covers several of these aspects, starting from the basic drive system and its control. It is hoped that this paper will benefit the researchers to have a quick birds' eye view of the past and current status in Variable Speed Drives.