Sensor fault tolerant control of doubly fed induction machines using multiple switching mechanisms

We propose a new strategy for sensor fault tolerant control of rotor wound induction motors operating as stand alone generators. The strategy employs three switching mechanisms that detect faults in, respectively, rotor current sensors, stator current sensors and stator voltage sensors. Each of the switching mechanisms receives measurements from the three phases and builds three residual quantities by combining these measurements pairwise. At each sampling time, the pair of measurements that yield the smallest value of the residual quantity are selected by the respective switching mechanism to implement a vector control law. The switching selection is such that measurements from faulty sensors are automatically avoided and only healthy measurements are used for control. Simulation results under realistic conditions illustrate the effectiveness of the scheme.