The position sensorless control methods of DC+AC stator fed doubly salient electromagnetic motor (DSFDSEM) covered full speed range are presented in this paper. To implement these methods, the followings are done. Firstly, the series self-inductance area difference method in consideration of cogging torque produced by field current is adopted for identifying the initial position. Secondly, the current pulse injection technique in the commutation point is proposed to detect the commutation moment in the low speed. At last, the terminal voltages are considered as vectors with fixed phase difference and the composed vector is rotated with the varying rotor positions, the commutation point can be obtained by coordinate transforming of three terminal voltages in the high speed. The filter with low cut-off frequency is not required in this method. Moreover, the smooth switching technology between start-up and high-speed operations is researched to prevent the fault of out-of-step. The sensorless control of DSFDSEM from start up at standstill to high-speed operation can be implemented easily by the methods mentioned above. No additional hardware or complex computation is required. A 12/8 DSFDSEM prototype is built and tested to verify the feasibility of the proposed sensorless schemes.Index Terms-Current pulse injection technique, terminal voltage vector, smooth switching technology, sensorless control, DC+AC stator fed doubly salient electromagnetic motor (DSFDSEM), full speed range.

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.

No abstract

No abstract

In this paper, a three-phase dual armature-winding doubly fed doubly salient electromagnetic generator (DAW-DFDSEG) is proposed. The reason for using different numbers of turns in the two sets of armature windings is presented. On the basis of the finite-element method (), two different DAW structures (DAW1 and DAW2) with different turn numbers of armature windings are analysed and compared. The DAW2 structure outputs more power than DAW1 under the same turn number of armature windings, due to the stronger flux-weakening armature reaction under heavy magnetic saturation. However, the manufacturing technique of DAW2 is more complex than that of DAW1 in the limited stator slot. The DAW1 with two set armature windings of 11 and 12 is researched in detail in terms of flux linkage, induced voltages, winding voltages, winding currents, self-inductances and mutual inductances by simulation and the equivalent rectifier circuit patterns of two time zones are also presented. Meanwhile, its commutation procedure is analysed in detail. To validate the analysis, a 12/8-pole DAW-DFDSEG prototype has been designed and the simulated waveforms agree well with the measured ones.