Sensor Fault Tolerance Enhancement of DFIG-WTs via Perturbation Observer-Based DPC and Two-Stage Kalman Filters

This paper presents a sensor fault-tolerant control (SFTC) strategy, combining perturbation observer-based direct power control (PODPC) and two-stage Kalman filter (TSKF) to enhance the fault tolerance of a doubly fed induction generator-based wind turbine (DFIG-WT) subject to rotor and stator current sensor faults. In the PODPC scheme, the interactions between active and reactive power control loops are represented by newly introduced perturbation states, and the feedback linearization control is realized with the state estimations derived from perturbation observers to achieve the decoupled power control. No rotor current sensors nor parameters of DFIG-WT are required in the implementation of PODPC. Stator current TSKFs are designed to generate residuals for fault detection and isolation, and provide current estimations to replace the faulty current measurements for system reconfiguration under stator current sensor faults. Simulation studies undertaken on a grid-connected DFIG-WT system reveal that the proposed SFTC strategy is immune to rotor current sensor faults, and it provides strong fault tolerance to stator current sensor faults.