Passive Fault Tolerant Control of Induction Motors Using NBC

Abstract

This paper studies passive fault tolerant control (PFTC) of three phase induction motors (IMs). First, a nonlinear block control (NBC) transformation is applied to handle nonlinearities of motor faulty model. Afterwards, a fault tolerant speed controller is developed based on sliding mode control (SMC) technique with linear sliding surface. However, the utilized NBC transformation needs multiple derivatives calculations which make it computationally burden. In addition, this NBC transformation has unmatched fault rejection problem which SMC controller is not able to remove the fault. To avoid the mentioned drawbacks, a novel and simple NBC transformation is proposed for IM. Also, a new nonlinear sliding surface is presented in order to enhance the SMC controller performance. Comparative simulations demonstrated performance of the proposed controllers for matched and unmatched faults and load torque uncertainties.