Feedforward Fault-Tolerant Control for Three-Phase Induction Motor Drives with Single Open Circuit Fault

Due to inevitable prospect of failure in power electronics, the demand for reliability improvement in adjustable speed drives become important, particularly for the induction motor drives being widely used in the industry. In this study, a mathematical approach is introduced to elucidate the relation between the controller output and applied voltage to the motor terminal, the place in which the fault might occur. The relation is derived based on the comparison of healthy and postfault operation of induction motor drives controlled in a field-oriented control (FOC) manner. Without any modification to the overall closed-loop controller structure, the fault is perceived as a disturbance to the system. Based on this approach, the lumped impact of the open-circuit fault (OCF) and topology reconfiguration is identified and compensated by injecting a suitable feedforward term. The effectiveness of the proposed fault-tolerant controller is verified and compared through the simulation and experiment, ensuring the smooth operation in postfault mode.