Study On The Control Of VSCF Doubly-Fed Wind Power Generator

It is of great significance to develop and utilize wind power, which is not only renewable but also without pollution when energy source scarcity and environmen pollution are getting more and more serious. Wind power generation technique improved greatly thanks to that more and more countries all over the world pay attention to it. With the increasing scale of wind power generation system, the investigation on wind power generation technique has been focused on improving the operation efficiency of wind power generation. For this reason, the technique of variable speed constant frequency (VSCF) operation which is capable of capturing the maxim wind power, becomes research hotspot.With the control of VSCF doubly-fed induction wind power generator system as the research subject, this dissertation made depth study from theory to the simulation. First,this dissertation analyzes the equivalent circuit of the doubly-fed induction generator, power relationship of DFIG , coordinate transformation and mathematical model of DFIG.On this basis, in order to realize decoupled control of DFIG active and reactive power and to capture the maximum wind power, field oriented vector control technique was applied to DFIG control. A general control strategy based on stator flux oriented vector control was proposed as well. The second, the characteristics of dual PWM converter, which is used for DFIG excitation, and the difference between rotor-side converter and grid-side converter in control and function aspects was discussed. The control principle of grid-side converter, the function of which is to control the input power factor at grid side and DC bus voltage, was designed on the basis of the field oriented vector control.Finally, the operating characteristics of the wind turbine and the maxim wind power capture operation principle was discussed. And the maximum power capture scheme by the way of DFIG power control was put forward.In simulation, the simulation model of a wind turbine was founded, On this basis, the whole simulation model was founded too. The Simulation results testify the validity of the theory and the control strategy proposed...