The Optimization On Direct Torque Control System Of Brushless Doubly-fed Machine

At present, more and more researchers pay attention to the wind energy source which is a green energy when the renewable energies just like coal, oil and so on become less and the energy consumption increases quickly. The development speed of the VSCF wind power technology is fast in the occident. Usually, the wind generator used brush doubly-fed machine. But the brush is a great defect in the wind generator. The generator need maintain frequently because of the brush which influences the operation reliability of the system too. Because of the problem, lots of the researchers devote their mind to the Brushless Double Fed Machine (BDFM). The BDFM can doubly-fed operation in the condition of brushless which operates reliability and maintains easily. The power of the inverter accounts for little in the total power of the motor when the BDFM works as a motor. Therefore, the cost of the speed governing system is reduced. So the BDFM has the widely development prospect in the wind power, hydraulic power system and the large capacity of electrical transmission system. Many researchers focus in it in recent years. This paper researches magnetic chain observation strategy, asynchronous start-up process and led into the synchronization strategies in the foundation of the BDFM direct torque control system. The paper’s main content includes some aspects in the following(1)The magnetic chain observer is a key to the BDFM direct torque control strategy. It affects the success of the control strategy. In order to solve the problem of the magnetic chain observation in low frequency, this paper improves orthogonal nonlinear method on the based of studying it deeply, correction parameters and experiment. The result shows that the improved orthogonal nonlinear method in super low frequency can be accurately observed magnetic chain to1Hz. It has a well control effect.(2)The starting method and performance are very important to any kinds of motors. For BDFM, asynchronous starting method is also a key problem to research BDFM pulling into the synchronization mode. This paper realize asynchronous start of rated voltage by hair zero vector. The current and start torque when asynchronous starting is studied and experiment based en analyzing BDFM equivalent circuit.(3)In order to improve transient process of leading into synchronization, a priority magnetic chain control method is put forward on base of researching switch table. The experiment result shows that this method is effectively reduced current of power winding, shorten the dynamic time.(4) The research is on the basis of our group reactive power control,and by the introduction of the BDFM direct torque control system, the simulation model is established and simulated.Simulation results show the effectiveness of the method. (5)The programme and system implementation are completed which based on digital signal processing chip TMS320F2407A in the platform of the BDFM experimental platform in this paper. The magnetic chain observation, asynchronous starting method and pulling into the synchronization mode experiments are made based on the syetem.