Induction motor torque closed-loop vector control system based on flux observation and harmonic current suppression

As for the torque control system of induction motors, there are generally two technical problems. One is the torque feedback error caused by the low accuracy of the flux observer, and the other is the torque ripple caused by insufficient harmonic current suppression. In order to provide accurate electromagnetic torque feedback information, an improved voltage and current hybrid model-based flux observer is designed, which improves the effectiveness of flux observation and the accuracy of electromagnetic torque feedback. Furthermore, an improved quasi-resonant linear active disturbance rejection-based current loop control method is proposed to suppress the harmonic current and reduce the torque ripple. And the disturbance observation characteristics, parameter influence, and self-stability of the control system are analyzed based on the frequency domain method. Finally, to verify the effectiveness of the proposed method, simulation, and physical experiments are designed in this paper. The experimental results show that the proposed method can effectively reduce the flux observation error and the current harmonic component, and thus greatly improve the torque tracking control performance.