A new transfer function of an induction motor driven by variable frequency source

This paper describes an advanced control algorithm to realize the fast response of an inverterfed induction motor, and the characteristics obtained by this control algorithm. The algorithm, mentioned here, makes it possible to control two vector components of an induction motor, namely, a secondarily interlinked flux vector and a secondary current vector which intersects with the flux vector at a right angle, separately. The transfer function of the induction motor controlled by this algorithm is very similar to that of a separately excited dc motor. And the transient characteristics of the control system are derived by means of the transfer function where the time delays of the responses of primary currents and secondary currents caused by the inductances of an induction motor are taken into consideration.