Direct flux vector control scheme for induction machine drives with space vector modulation

In this paper, an improved torque controller of induction machine based on direct control of stator flux linkage vector is presented. The fundamental relationship between the rotating speed of the stator flux linkage and torque is analyzed and the design principle of controller is presented. A simple structure with only one proportional-integral (PI) controller is shown to implement the torque and flux control adequately. Parameters of PI regulator are easily found in the proposed design principle. Robust design of the direct flux vector ensures the system is not sensitive to the variation of rotor resistance. Fixed switching frequency and low torque ripple are obtained with PI control and space vector modulation (SVM) method. Satisfactory modeling results indicate the feasibility of the proposed direct flux vector control scheme.