A Parallel Speed and Rotor Time Constant Identification Scheme for Indirect Field Oriented Induction Motor Drives

Rotor time constant identification is necessary for high-performance indirect field oriented control of induction motor drives. Meanwhile, speed sensorless technique has many advantages such as low cost and reduced hardware complexity. In recent years, the estimation methods for motor speed have respectively grown to maturity, but the research in the identification of rotor time constant remains to be extended. In this paper, an online scheme for parallel motor speed and rotor time constant identification is proposed according to parameter features, with the operating frequencies of all modules carefully considered. First, the speed is estimated via rotor slot harmonic extraction technique. On the premise of estimated speed, a derivative form of induction motor model is proposed for rotor time constant identification, which overcomes the problems of pure integration in rotor flux calculation. Correspondingly, instead of rotor flux, derivative rotor flux is used in the proposed model. Finally, an adjusted particle swarm optimization method is utilized on the proposed model to track the rotor time constant. The robustness and effectiveness of the proposed scheme have been validated experimentally.