Investigation of fault-tolerant capability of five-phase doubly salient electromagnetic generator
A new topology of five-phase fault-tolerant doubly salient electromagnetic generator (FTDSEG) is proposed for high reliability applications in this paper. The analysis of no-load and loading operations shows the potential fault-tolerance capability. On the basis of comparative analysis on structure characteristics between five-phase non-FTDSEG (NFTDSEG) and five-phase FTDSEG, the variation of rotor pole number from NFTDSEG to FTDSEG is revealed. Meanwhile, the flux linkage and electromotive forces (EMFs) of five-phase NFTDSEG and five-phase FTDSEG are investigated with finite element method and five faults of five-phase FTDSEG are analysed in detail. Especially when single phase short-circuit fault happens, the magnetic field of the motor, flux linkage of short-circuit phase and short-circuit currents without load are investigated in four different short-circuit moments and the fault is in consideration of armature winding resistance. The ultimate variation trend of flux linkage is irrelevant to moment when the short-circuit fault happens. The flux linkage and EMF of short-circuit phase are also analysed. The laws of fault operating influence on external and power characteristics of FTDSEG are researched in five faults with different exciting currents. The fault-tolerant ability of five-phase FTDSEG has been demonstrated by the experimental results.