Stability analysis of full order observer based speed sensorless induction motor drive

Stability of full order flux observer based speed sensorless control system is studied in the paper. By small signal analysis method, the whole control system is linearized and transfer function from speed reference to practical speed is obtained. Examining pole distribution of transfer function, stability analysis is carried out. The impact of motor parameter error on speed identification system is considered. Besides, research is made on the relation between lowering bandwidth of speed identification loop and control loop and improving speed sensorless control system stability. Simulation and experiment results validate the analysis in the paper.