Application of the extended Kalman filter in current sensors fault-tolerant control of the induction motor drive

Information about the actual current signal is essential in all modern control structures of induction motor (IM) drives. Unfortunately, stator current sensors (CSs) are prone to failure. Therefore, in this paper, fault-tolerant control (FTC) against current sensor faults for an IM drive is proposed. The detection and compensation of CS faults is based on the extended Kalman filter (EKF). To increase the current estimation performance, the state vector is expanded by the coefficient of change of both resistances of the IM. Simulation studies demonstrate the effectiveness of the proposed approach for different types of CS faults, such as gain change, offset, saturation, or complete signal loss, and under different operating conditions of the IM drive, including regenerative braking. The short detection time and high quality of stator current reconstruction in a wide range of speed and load torque make the presented solution universal for any IM drive with increased safety requirements.