Robustness Improvement of Induction Motor Model Predictive Control System Based on Rotor Time Constant Identification

In the model predictive current control (MPCC) based on indirect field-orientation, the accuracy of the rotor time constant directly affects the precision of field orientation. Due to various reasons such as magnetic saturation and temperature changes, the rotor time constant varies. This paper analyzes the influence of rotor time constant errors on field orientation and proposes a method to compensate for the rotor time constant using output torque. When orientation error exists, change the excitation current to switch the operation point and then use the difference in the measured output torque at different operation points to identify the rotor time constant. With the proposed algorithm, the impact of rotor time constant errors can be reduced. Simulation verifies the feasibility of the proposed method.