Vector control has become a powerful and frequently adopted technique in recent years. The implementation of vector-controlled techniques has enabled induction and synchronous machine drives to be used for high performance applications where previously only DC drives could be used. This book discusses in detail the various forms of vector control of smooth-air-gap and salient-pole electrical machines supplied by impressed stator voltages or currents or impressed rotary currents. The 4 types of vector-control considered are; rotor oriented, rotor-flux-oriented, stator-flux-oriented and magnetizing-flux-oriented control. Other topics covered include the necessary decoupling circuits, the effects of non-ideal drives, and rotor speed and rotor resistance identification by means of model reference adaptive control theory. It is aimed at student's and those working in industry and universities who require an understanding of the various aspects of the space phasor and generalized electrical machine theories and the control of variable-speed AC drives.