The Power Tracking Control Design For Doubly-Fed Induction Generator

Since the end of last century, the world began to focus on renewable energy development and utilization due to the energy crisis. Among these renewable energy sources, wind energy not only has the advantages of no environmental pollution and short construction period, but also land saving, available for whole day and huge reserves, etc. Therefore, it has become one of the most important and promising development of renewable energy sources. With the wind turbine capacity increasing, improving the operating efficiency and increasing the conversion rate of wind energy have become an important part of research in wind power technology. The theme of this thesis is the most power tracking control design of VSCF Doubly-fed Induction Generation, with a comprehensive and in-depth theory analysis and simulation.First, this paper introduced the characteristics and operation theory of DFIG. Then, the principles of MPPT (Maximum Power Point Tracking) and the decoupled control of DFIG active&reactive power are studied. The mathematical models of the DFIG in both abc and dq coordinate are established. Based on the characteristics of the mathematical model of DFIG and MPPT demands, the field oriented vector control strategy is proposed.Considering the drawbacks of classical PI controller, a P+C controller is proposed. According to the MATLAB/SIMULINK results, the P+C controller has a better response performance and senseless to disturbance. However, the P+C shares the same problem with PI---the control parameters cannot be changed, which limits its use in nonlinear time varying system with wide variation of parameters. A Fuzzy PI control strategy is introduced to overcome the shortages of conventional PI and P+C. The MATLAB/SIMULINK results demonstrate its validation during wide variation of parameters, meeting the system demands on the rapidity and robustness.