Fault-tolerant control of doubly-fed induction generators under voltage and current sensor faults

This paper presents a Kalman filter-based fault-tolerant control (KFFTC) strategy for a doubly-fed induction generator (DFIG) under voltage and current sensor faults. Based on the independent time-varying models of stator voltages, stator currents, and rotor currents, six Kalman filters are designed in parallel to estimate voltage and current components in the presence of measurement noise. The sensor faults are detected and isolated based on the residuals calculated from observations obtained by sensors and estimations provided by Kalman filters. The faulty measured signals are then replaced by the estimated signals derived from corresponding Kalman filter to reconfigure the control system of DFIG during the sensor faults. Simulation and experimental studies undertaken on a grid-connected DFIG system reveal that the KFFTC strategy is able to correctly detect the sensor faults and isolate the faulty sensor, and it ensures the fault-tolerant operation of DFIG under the conditions of stator-voltage, stator-current, and rotor-current sensor faults.