Analysis of a new five-phase fault-tolerant doubly salient brushless DC generator

The fault-tolerant ability of a multi-phase doubly salient electromagnetic generator (DSEG) makes it suitable for important applications. However, asymmetric phase windings are a drawback of the traditional five-phase DSEG. This study presents the design of a new five-phase brushless DSEG with symmetrical phases and a robust rotor. The proposed stator poles, rotor poles, and their pole arc criteria form a general design basis for the multiphase DSEG with minimum cogging torque. The proposed new winding configuration overcomes the phase asymmetry drawback of the traditional DSEG. An analysis of the characteristic of the no-load and the loading operation of the five-phase DSEG shows that the five-phase DSEG has fewer harmonics than the three-phase DSEG does. Additionally, the five-phase DSEG has high fault-tolerance ability because adjacent phases will take over the activity of the fault phase if there is an open-circuit fault. Simulated and experimental results of machine performance under the same working conditions offer verification of the design principles presented.