Fault-Tolerant Control of Nine-Phase Induction Motor With Sensorless Speed and Flux Estimation

Design and application of fault-tolerant control (FTC) in multiphase drives are essential in safety-relevant applications such as electric vehicles, space vehicle drives, chemical industrial drives etc. A nine-phase motor endure to operate with rotating magnetic field (RMF) as long as no more than six phases are faulted. This paper proposes a fault-tolerant control for nine-phase induction motor drive, in which a single switch open-circuit fault is occurred in the nine-phase inverter feeding the motor. The proposed FTC reconfigures the current references to the motor controller in such a way to avoid the overheating in healthy phases due to stator copper losses. A sensorless field-oriented control is employed for the speed and torque control of motor drive. The proposed sensorless control scheme employs an Extended Kalman Filter (EKF) algorithm to estimate the rotor speed, rotor flux, and rotor field position without using any speed and flux sensors which make the system more reliable and less sensitive to motor parameter variations, disturbances, and speed encoder faults. Credibility of the proposed FTC is evaluated in MATLAB/SIMULINK platform.