Very low speed performance research of novel voltage vector control method for IM

A novel voltage vector control method for induction motor is presented to improve the low speed performance and stability of open-loop system. The control scheme adopted a novel voltage boost method to compensate the stator resistor voltage drop keeping the magnitude of the stator flux constant. And through deeply research of the instability under light load condition, a stabilizing control method was proposed. Under very low speed condition, the performance had been greatly improved by boosting the torque and compensating the motor slip frequency. Different from vector control methods, all the compensation and regulation were based on stator voltage oriented synchronous rotation frame transformation, which avoided complicated flux linkage vector calculation and were simple to implement. The experimental results show that, by adopting the proposed method, the speed can be accurately controlled down to 5.3 r/min with rated load torque. Great improvement is achieved in the low speed performance and speed accuracy, and the system under no load condition is stabilized at the whole operating range.