The Study On Design And Analysis Of Brushless Double-Fed Machine With Blocked-Magnetic Reluctance Rotor

The Brushless Double-Fed Machine (BDFM) not only features simplicity, has the robust mechanical characteristics together with controllable speed and power factor, but also can realize easily asynchronous, synchronous and double-fed operation modes. Being acted as an adjustable speed system using conventional AC machine, the BDFM could reduce the capacity of transducer and the adjustable speed cost. The multi-pole BDFM has higher reliability because of ignoring the gearbox. The cost of machine is reduced because the reluctance rotor is adopted. Therefore, it is a challenge task to continue related researches for BDFM.The study of BDFM is proposed in this paper. The main work of the dissertation is as follow:Firstly, through the understanding of the development history, actually researching and appliance foreground, combining with the literature of in and out country, the basic theory of BDFM is studied. The theory of adjustable speed with constant frequency of BDFM is analyzed, and the rotate speed formula and the relationship between electromagnetism power and the power supply frequency of power winding and control winding of BDFM's stator are obtained.Secondly, the design theorem of ALA rotor is imported in the salient reluctance pole rotor; in other wise, some deep troughs are added in the common salient pole reluctance rotor structure. The magnetic flux is ascertained because of the deep troughs, and the magnetic flux between adjacent poles. In this paper some different blocked-magnetic salient pole reluctance rotors are designed. It is known from comparative analysis of the motor magnetic field by the finite element method that the new rotor structure works better than the common salient pole rotor in terms of the magnetic poles modulation effect, which increased the magnetic transformation efficiency greatly. The BDFM with new rotor has the advantages of simple structure, easy to manufacture, asynchronous operation in single-fed state, high reliability and high magnetic transformation efficiency.Finally, the efficiency of the BDFM is analyzed. In this paper the reason of the stator and rotor loss of BDFM is introduced. And it also is analyzed to reduce the loss and improve the operating efficiency of the BDFM.