A dynamic decoupling method for speed-sensorless vector control of induction motor

This paper presents a decoupling method for speed-sensorless vector control of induction motor to track the flux command fast and eliminate torque ripples in flux-varying environment, such as field-weakening operation and efficiency optimization. Rotor flux-oriented control can decouple the speed and flux control. However, the decoupling is on the condition of a constant rotor flux. When motor drives operate in field-varying regions, the decoupling will fail. The method proposed in this paper can achieve dynamic decoupling between rotor flux and speed. Thus, the dynamic performance of flux and speed tracking can be improved when flux command varies rapidly. The proposed method can improve the dynamic performance of control of speed and rotor flux by adding a feed-forward controller. Comparison between the proposed method and traditional method shows that the performance is improved by the proposed method. A prototype based on TMS320F2812 DSP is built to carry out the proposed method. Simulation and experimental results verify the validity of the method.