Direct field-oriented control strategy for fault-tolerant control of induction machine drives based on EKF

Abstract

This study presents a novel direct field-oriented control (DFOC) strategy for fault-tolerant control of wye-connected three-phase induction machine drives under the stator winding open-phase failure. In the proposed control strategy, instead of flux measurement, an extended Kalman filter (EKF) for flux estimation is used. The introduced controller with minor modifications can be used during normal and stator winding open-phase failure conditions. With the proposed DFOC system, the speed and torque pulsations that normally happen during open-phase failure can be reduced. The performances of the proposed EKF-based DFOC strategy and the conventional control strategy for a faulted machine using simulations and experiments under different operation conditions are compared. Simulation and experimental results demonstrated an important improvement in speed and torque pulsations through this type of fault. Results also confirmed superiority of the proposed EKF-based DFOC scheme over the conventional control scheme to balance the faulted machine phase currents.