Current Sensor Fault-Tolerant Control for Direct Torque Control of Induction Motor Drive Using Flux-Linkage Observer

This paper proposes a novel fault-tolerant control (FTC) scheme for direct torque control of induction motor (IM) drives against the line current sensor failures. Three major steps involved in the proposed FTC scheme are the detection of sensor fault, isolation of the same, and finally, the reconfiguration by proper estimation. Thirddifference operator employed in the motor line current is found suitable for the detection of the sensor fault, while flux-linkage observer-based current estimation scheme performs the task of estimation of line current post the occurrence of the fault. Furthermore, a decision-making logic circuitry isolates the faulty signal and simultaneously selects the appropriate estimated current signal to make the drive fault-tolerant. The proposed current sensor FTC scheme is simple and unique in nature. Moreover, it can be universally applied with any speed control schemes involving IM drive. The proposed scheme is simulated and extensively tested in MATLAB/ Simulink. The obtained simulation results are also verified using a dSPACE-1104-based IM drive laboratory prototype to show the effectiveness of the scheme.