Balakhontsev O. Real-time identification of asynchronous drive's parameters and coordinates.

Thesis deals with identification of induction motor’s parameters and indirect estimation of its coordinates under maintenance in vector-controlled electric drive. A new method for identification of stator and rotor ohmic resistances of induction motor is presented. The method is based on AC motor’s discrete model which was obtained by z-form discrete approximation relative to state variables. Resistances identification requires only data about stator current and voltage and motor speed. Unlike existing approaches the method proposed does not requires special testing signals or procedures. This allows its running in real-time mode without interfering in manufacturing process. A new approach to indirect estimation of induction motor speed under drift of its ohmic resistances is proposed. The speed is observed via instant values of motor’s voltage and current. The observer is obtained on the basis of discrete equation describing current circuit of induction motor. Unlike existing observers, the approach proposed estimates speed despite of motor’s operating mode and does not require flux determination. The approaches and methods were verified experimentally. Their high efficiency and accuracy are proven. Recommendations for practical introduction of identification system are given. Key words: asynchronous vector-controlled electric drive, discrete model, parameters estimation, identification, speed observer.