Vector control of AC motors

The standard AC induction electric motor is used in over 90% of all applications. However, the disadvantages of fixed-speed operation have led industrial users to seek and use other means to achieve variable speed drive operation. Recent developments in power semiconductors and microprocessors have resulted not only in economical advantages but also improved performance and greater speed range and torque control. Many of the considerations for successful application of vector drives are described, and its advantages and limitations are highlighted. It is shown that vector control techniques can be applied successfully to standard squirrel cage induction motors.