The Study On Electromagnetism Construction Analysis And Simulation Of Brushless Double-Fed Machine

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 BDFM can be widely applied in fan, pump and adjustable speed constant frequency generator system, such as waterpower and wind power, so the study of BDFM is regarded by many researchers.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 through power view, 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 configuration of BDFM is analyzed. Because the BDFM is composed with power winding and control winding of stator, two winding modes are given, the one is single winging and the other one is double winding. Then the characteristics of these two kinds of windings are analyzed and the configuration of single winding is analyzed especially. Subsequently, the form of squirrel cage rotor and the selection of rotor bar number are analyzed roundly, so the theoretical foundation of electromagnetic design and parameter optimizing for brushless double-fed machine is given.Thirdly, the stator configuration of BDFM is special, so there is no any coupling in electric and magnet directly in the two sets of windings and the electric magnet power is transferred indirectly through rotor winding, so the analysis of steady state performance of BDFM is very different form that of conventional electric machines. The frequency of every winding is converted to the same value by using frequency-conversion method. The equivalent circuit and the phasor diagram are gained. Using the phasor diagram, the electromagnetic torque and power equation are analyzed. Then the magnetic field distribution, every harmonic produced by both...