Evolution of Controllers for the Speed Control in Thyristor Fed Induction Motor Drive

Induction Motors (IMs) are now becoming the pillar of almost all the motoringapplications related to the industry and household. The practical applications of IMs usually requireconstant motoring speed. As a result, different types of control systems for IM's speed controlling havebeen shaped. One of the important techniques is the utilization of thyristor fed drive. Although, thethyristor fed induction motor drive (TFIMD) offers stable speed performance, the practical speed controldemand is much more precise. Hence, this drive system utilizes additional controllers to attain precisespeed for practical applications. This paper offers a detailed review of the controllers utilized with thethyristor fed IM drive in the past few decades to achieve good speed control performance. The clear intentof the paper is to provide a comprehensible frame of the pros and cons of the existing controllers developedfor the TFIMD speed control requirements. 
Keywords: Thyristor Fed Drives, Induction Motors, Speed Controller, Conventional Controllers, andSoft Computing Techniques.