Fault-Tolerant Strategy against Current Sensor Failures for DTC-SVPWM based Induction Motor Drives

The present paper illustrates a fault-tolerant control (FTC) scheme against line current sensor failures in direct torque control (DTC) of induction motor (IM) drives using space vector pulse width modulation (SVPWM) technique. In this paper, the current sensor fault has been detected using a third-difference operator (TDO). Further, the fault isolation and reconfiguration of the system are achieved using an AND-OR latch-based decision-making technique. The proposed method employs a current estimator in stationary reference
$(\alpha- \beta)$
frame and a soft switch is used for feeding the estimated currents over actual currents to the DTC-SVPWM controller in case of current sensor faults. This renders the design of the FTC scheme novel, simple, and independent of control regime. MATLAB/ Simulink is used to simulate the proposed scheme and its performance and effectiveness are verified in hardware domain using the dSPACE-1103 based 5.5 kW IM drive experimental setup.