On the analysis, estimation and control of field oriented induction motor drives.

摘要

The focus of this research is on the analysis, estimation, and control of field oriented induction motor drive systems. The performance of an indirect field oriented controller degrades when the motor parameters change, specifically the rotor resistance. This is the so called detuning problem. To overcome the detuning problem, a rotor flux observer based Model Reference Adaptive System (MRAS) scheme for on-line rotor resistance adaptation is designed and implemented. This dissertation also presents a solution to the problem of accurate flux, position and velocity estimation. A current model flux observer is designed which uses the sliding mode technique. The flux observer in this technique does not require any knowledge of the rotor time constant or the machine speed because both are included in the sliding mode function, thus making the proposed observer completely insensitive to any error in the rotor time constant or the machine speed information. Finally, the performance of speed regulation is improved by designing two intelligent controllers which are a standard fuzzy logic controller with a dynamically focused learning algorithm added to it and a continuous sliding mode controller.