Fault diagnosis and tolerant control for speed sensors based on state observers in induction motor drives

Speed sensor is an important part of induction motor vector control system, its fault can cause system degradation. Firstly, a vector controlled induction motor drive system is designed, and then a state observer based speed sensor fault diagnosis and its fault tolerant control are fulfilled. When the speed sensor is in healthy condition, the state observer works in a diagnosis mode; if faults occur in the speed sensor, it acts as a speed estimator. The control system smoothly switches from the vector control mode with a speed sensor to a speed sensorless vector control mode, so the speed sensor fault tolerant control scheme is established. Finally, the validation of this method has been proved on a dSPACE experimental platform.