Research On The Model Establishing And Simulation Of Brushless Doubly-fed Machine

Now, a large number of applied AC machines are mainly the synchronous machines and induction machines.Generally, synchronous machine and induction machine can not be used together because of the structural differences.The brushless Doubly-Fed machine(BDFM) not only has a simple structure of rotor cage, but also has the fine characteristics of the wound rotor induction machine and synchronous machine that can operate on both the synchronous and asynchronous status,not only can be used as an adjusting-speed machine, but also as a variable-speed constant-frequency(VSCF) generator, and the doubly-fed electricity can be realized under the brushless case.A wound-rotor BDFM is taken as an example in the paper. At first, from the BDFM principles,A wound-rotor brushless doubly-fed machine is designed according to "pole-changing method" based on the ordinary cage-rotor BDFM, both the stator windings and rotor windings of the machine are designed in detail and the harmonic analysis is made simply. Then, the network mathematical models and d-q mathematical models of the wound-rotor BDFM are derived on the basis of the motor's windings designed, and the simulation model based on d-q reference frame is established. Various operating modes of BDFM are simulated, and the simulation waveforms are drew in the motor's various operating modes. The correctness and feasibility of the model are verified by the reasonable simulation results.Then, the flux-oriented control strategy of the BDFM is derived based on vector control of the conventional induction motor. In the control strategy, according to frequency of the power windings and control windings, the two sets of synchronous reference frame are used, the power windings and control windings are established based on their own synchronous reference frame, the BDFM is divided into two independent subsystems,to realize decoupling magnetic field by regulate respectively, so as to achieve good control performance.And then, the realizing algorithm of the control strategy is derived based on the flux-oriented control strategy, and the voltage space vector (SVPWM) control framework based on DSP is introduced briefly.Finally, a summary about the thesis is made. Some suggestion is proposed for next work.