Fault Tolerant Control for Speed Sensor Failure in Induction Motor Drive based on Direct Torque Control and Adaptive Stator Flux Observer

this paper deals with a speed sensor fault tolerant control (FTC) scheme for induction motor (IM) drive based on direct torque control (DTC) and adaptive stator flux observer (ASFO). Many important points are treated in the proposed algorithm, which are the detection of the sensor failure, isolation of the faulty sensor and the reconfiguration of the control system by proper estimation. An adaptive stator flux observer is used instead of classical flux and torque estimator to perform the stator flux components, electromagnetic torque, flux magnitude, rotor position and the estimated rotor speed. Furthermore, a fault detection and isolation (FDI) logic circuitry is used to detect speed sensor fault and isolate it and simultaneously generate a logic impulse to switch to the sensorless mode. The proposed algorithm is simulated in MATLAB/Simulink.