A real-time sensor fault detection, isolation and reconfiguration method for vector controlled induction motors based on Extended Kalman Filter

Vector controlled motor drives are widely used in industry application areas, usually they contain two current sensors and a speed sensor. A fault diagnosis and reconfiguration structure is proposed in this paper including current sensor measurement errors and sensors open-circuit fault. Sliding windows and special features are designed to real-time detect the measurement errors, compensations are made according to detected offset and scaling values. When open-circuit faults occur, sensor outputs are constant-zero, the residuals between the Extended Kalman Filter (EKF) outputs and the sensors outputs are larger than pre-defined close-to-zero thresholds, under healthy condition, the residuals are equal to zero, as a result, the residuals can be used for open circuit fault detection. In this situation, the feedback signals immediately switch to EKF outputs to realize reconfiguration. Fair robustness are evaluated under disturbance such as load torque changes and variable speed. Simulation results show the effectiveness and merits of the proposed methods in this paper.