Demagnetization faults in permanent magnetassisted synchronous reluctance motors (PMa-SynRMs) can lead to deterioration in the control performance of the drives, if the implemented PM flux linkage parameter is different from the actual value. To increase the robustness against demagnetization faults, a novel fault-tolerant control method is developed for PMa-SynRM drives. In the proposed method, an extended Kalman filter is used for online estimation of the PM flux linkage, which is tuned adaptively in the control algorithm, including the maximum torque per ampere strategy. The effectiveness of the proposed demagnetization fault-tolerant control technique is demonstrated by numerical simulations.