A Novel V/f Scalar Controlled Induction Motor Drives with Compensation Based on Decoupled Stator Current

A novel open-loop scalar control method for induction motor that provides desirable operation in low frequency is presented. The control scheme is based on the popular constant volts per hertz (V/F) only using the current sensors. Based on the mathematical model of the induction motor, the rotor flux vector is estimated to decouple the stator current. The slip frequency and the current-resistant (IR) stator voltage drop are estimated and compensated based on flux and torque component of the stator current in the rotor-flux oriented reference frame. It shows that, by using the proposed method, the speed can be controlled down to 1Hz with full load torques.