Stator-flux oriented continuous control of torque in induction motors

Abstract

This paper analyzes dynamic equivalent circuit of induction motor and the relationship among inner fluxes, then presents a direct stator flux oriented continuous torque control (DSFOCTC) scheme of induction motor, which uses stator current vector control instead of voltage vector control. As a combination of direct torque control (DTC) and flux-oriented vector control, it achieves round stator flux and continuous dynamic torque control resulting in less torque ripple than that in DTC. It reduces the dependence on rotor parameters, and is especially insensitive to rotor resistance. Finally, an induction motor speed control system incorporating this novel scheme is given and checked by simulation.