A fault-tolerant technique for Delta-connected vector-control AC motor-drives

A fault-tolerant technique valid for both open-loop and vector-control motor-drive systems is introduced in this paper. The technique is merely presented for AC motors with Delta-connected circuits in their stator windings. Hence, it enables the operation of the three phase motor upon a failure in one of its phases without the need of a special fault detection algorithm. This technique is to significantly mitigate torque pulsations, which are caused by an open-Delta configuration in the stator windings. The performance of the fault-tolerant technique was experimentally verified using a 5-hp 460V induction motor-drive system and the results are presented in this paper.