A novel stator voltage oriented V/F control method capable of high output torque at low speed

A novel stator voltage oriented V/F control method for induction motor is presented in this paper to improve the low speed performance and stability of open-loop system. The control scheme adopts a novel stator resistor voltage drop compensation method to ensure the rated stator flux constant over a wide range of operating speeds. And through deeply research of the instability under light load condition, a stabilizing control method is proposed. Under very low speed condition, the performance has greatly improved by boosting the torque and compensating the motor slip frequency. Different from vector control methods, all the compensation and regulation are based on stator voltage oriented synchronous rotation frame transformation, which avoid complicated vector calculation and are simple to implement. The experimental results showed that, by adopting the proposed method, the speed can be accurately controlled down to 0.1 Hz with rated load torque.