Research On The Control Strategy Of VSCF Wind Turbine

Wind Power is becoming more and more popular nowadays. For wind energy Conversion, the most widely used technology in the world is Variable Speed Constant Frequency (VSCF). This thesis generally introduces and further studies the power electronic converter technology and the control strategy of wind turbine base on the basic theory and computer simulation. The main contents are as follows:Firstly, this article summarizes the basic theories of the aerodynamicist, operating principle and characteristics of DFIG. The mathematical models in different coordinates are deduced in detail. This article also summarizes the basic strategies and realization method according to the Control on Variable Speed Constant Frequency System for Doubly-fed Generator.Secondly,this article summarize basic principle, mathematical models and wave-shape modulation base on the SVPWM method. A new Hybrid SVPWM was proposed when the traditional areas has been divided. The sector was divided by comparative study on the root mean square (RMS) ripple of different switching sequences. This scheme greatly reduces the flux ripple, by employing the different sequences in different areas.Then, the paper discuss the basic strategy of sliding mode control (SMC), applying to the doubly-fed wind power generation system. The simulation research is carried out on the platform of MATLAB/SIMULINK to doubly-fed wind power generation system Based on the stator voltage orientation. The Integral Sliding Surface and proportional component of controlling end is introduced to the traditional second-order sliding mode algorithm. The results of simulation indicate that the proposed strategy effectively achieve good control targets with the fine robustness.Finally, the paper evaluates the controller design of VSCF wind power generation system. The Working field of operating generation system is divided by studying on the chief control strategy in different Working field. The paper also introduces the design method of external controller. The Comparative simulation is carried out by the control strategy included PID algorithm,first-order algorithm and second-order sliding mode algorithm.