A fault-tolerant triple three phase induction machine

Abstract

This thesis focuses on the development of a fault tolerant induction motor which is capable of continued operation with winding and power converter short-circuits. The motor takes advantage of a segmented stator to function under extreme circumstance. When splitting a motor stator into separate segments of power, there is still coupling between segments, which is minimised by partitioning the motor into a series of circumferentially separated arcs. In this way, each segment of the stator is electrically, thermally, physically independent and each arc can be viewed as a linear motor; however, it has been found that the motor cannot be functional as a normal motor at all speeds. The reason of that phenomenon will be studied and concluded to be the large asynchronous space harmonics produced by each arc, which prevents the system from functioning successfully. According to the reason, a modified rotor is introduced which overcomes this problem and allows operation with not only open circuit, but also in short circuits for what is believed to be the first time