Innovative Extended Kalman Filter in a Coherent System for Detection and Compensation of Various Current Sensor Faults in the Induction Motor Drive

Measurement sensors, such as current sensors (CSs), are key components of any advanced AC motor drive. To ensure the highest quality and safety of the drive, CS faults, as well as significant measurement disturbances, must be detected and compensated for. This article presents the current sensor fault-tolerant control (CS-FTC) system using innovative extended Kalman filter (d-EKF) for induction motor (IM) drive. The parametric uncertainty correction factor estimated by d-EKF allows us to improve the quality of stator current estimation. The presented d-EKF not only performs CS fault compensation, but also provides reference signals to the residuum-based fault detector. The proposed CS-FTC enables the proper and stable speed regulation in the vector-controlled drive, also in a postfault mode. An experimental validation of this solution, carried out over a wide range of speed and load changes in postfault operation, confirmed the high quality of the stator current reconstruction and demonstrated the advantages and limitations of using the proposed d-EKF in the CS fault detection algorithm for the most frequently occurring types of CS faults.