SI Signal Injection

Abstract — Use of AC electrical machines in controlled electrical drive applications is reviewed. The major types of electrical machine are briefly summarized to set context and to establish the physical basis for the control techniques used. Machine properties are the key to successful control and can be obscured by the necessary mathematics required for machine analysis and control scheme derivations. The main focus of the paper is on control techniques which are being applied to make AC drives a rapidly growing area. Development of the control is discussed concentrating on recent trends suitable for practical applications in industry with good dynamic behavior. A particular feature is the increasing importance of speed or position sensorless techniques. Index Terms — AC machines, sensorless control, variable speed, electrical drives, controlled drives, vector control