Developments of machine model and a universal controller for vector-controlled induction motor drives will be presented in this paper. The machine representations associated with vector-control methods referring to various frames, including stator, rotor, and air-gap flux frames, can be derived simply by selecting different state variables; thereby clearly identifying the relationship between machine modeling and vector control. Moreover, a universal vector controller for induction motor drives fed by a voltage-controlled voltage source inverter will be presented. It will be shown in this paper that various vector controllers, including rotor flux-oriented controller, stator flux-oriented controller and air-gap flux-oriented controller, can be realized by simply changing few parameters. It will be demonstrated by experimental results that the developed universal vector controller for various vector-control approaches can be implemented using the same hardware with a minor change to software associated with parameters; and thereby confirming the theoretical analysis.