Study on Stability and Performances of DTC Due to Stator Resistance Variation

A stator-flux-based direct torque control (DTC) of induction machine has shown significant interests to researchers since its offer several advantageous compared to many other control schemes. This scheme requires only one parameter which is a stator resistance in order to estimate the stator flux-linkage, hence the electromagnetic torque can be directly calculated. In practice, a wide variation in stator resistance can occur due to a large temperature variation. Thus, the mismatch between estimated and actual stator resistances will deteriorate the performance of DTC by introducing errors in the stator flux estimation particularly at low speed. Consequently, the torque performance will be degraded. This paper presents the study on stability and performances of DTC due to stator resistance variation. The effect on DTC performances due to the stator resistance variation will be analytically studied with the help of simulation results.