
21-1
21.1 Introduction
Induction motors (IMs) are widely applied in many dierent types of industrial electric vehicles and
domestic drives owing to their well-known advantages like simple construction (squirrel cage rotor),
operation reliability, ruggedness, and low cost. Furthermore, in contrast to the DC brush motor with
mechanical commutation, these can be used in aggressive or volatile environments, since there are no
problems with spark and corrosion. ese advantages, however, are superseded by control problems
when using an IM in adjustable speed drives (ASDs). is is because an IM as a plant of feedback control
system has a coupled