Electric motor drives and control-past, present, and future

A comprehensive review of the state of the art in the field of electric motor drives and control strategies is presented. It is pointed out that drive technology has seen impressive growth during the last three decades. Recent advances in semiconductor power electronics and microelectronics have made is possible to use AC motors in many variable-speed drive applications. Implementation of new control techniques, such as field-oriented control and variable-structure control with sliding-mode features, has made AC motors a viable alternative to DC motors in high-performance drive applications. The advent of microprocessors/microcontrollers/microcomputers has made it possible to implement these complex control techniques