Fault tolerance in back-to-back three-level neutral-point-clamped induction motor drives

In this paper, the fault-tolerant capabilities of a back-to-back three-level Neutral-Point-Clamped induction motor drive are analysed. A strategy is proposed to manage fault-tolerant operation and the reconfiguration procedure, using minimal hardware expansion. This strategy includes diagnosis and tolerance solutions for IGBT open-circuit faults in both inverter and rectifier stages, thus guaranteeing a continuous operation of the motor and the maintenance of sinusoidal currents and unity power factor supply after the occurrence of a fault. Special attention is given to the reconfiguration procedure. Simulation results are included to demonstrate the good performance of the proposed strategies.