Broken rotor bar impact on the closed loop and sensorless control of induction machine

This paper presents analysis of closed loop and sensorless control of induction machine with broken rotor bar for on-line diagnostics purposes. Closed loop control system synthesis of induction motor is based on symmetrical model of the machine. In case of induction machine operation with broken rotor bars, rotor speed pulsation is compensated by the control system. Simulation of multiscalar control with the fault machine shows that decoupling variables can be used as detection signals. Analysis of speed observer frequency response in open loop operation gives information about disturbance impact on estimation error. Further analysis indicates that machine asymmetry can affect stability of sensorless control system with speed observer.