Modeling And Simulation Of Doubly-Fed Induction Generator And Studies Of Its Operating Characteristics With Grid

The problems of shortage of energy in world become more prominent, environment is damaged seriously, and all countries have focused on developing non-destructive and renewable new energy sources. Wind energy as the most competitive renewable energy sources has become the important goal of all national development, and significant results have been obtained. Currently, the main ways of wind power are constant-speed constant-frequency (CSCF) and variable-speed constant-frequency (VSCF) wind generation. The VSCF doubly-fed induction generator (DFIG) that has efficiency and practicality has become the mainstream model and researching field, with broad promising in the world. A modeling simulation of DFIG with grid which is based on vector control is completed according to the mathematical model of DFIG in this paper. The simulation results validate the correctness of modeling simulation of DFIG completed in vector control. And the QIEA (Quantum-Inspired Evolution Algorithm) is proposed to optimize the maximum power tracking point of wind turbine and the reactive power compensation in wind power with grid. The main thesis work and researching results are as follows:1. A modeling simulation of DFIG with grid system is established. First, the mathematical model of DFIG and the modeling simulation of wind turbine are analyzed. Second, the control strategy of DFIG is proposed to choose vector control strategy to realize the decoupled control of active and reactive power according to the mathematical model of DFIG. The vector control of grid-side voltage and rotor-side stator flux-oriented with delay circulation control is used to control dual PWM power converter, which simplify the control process and improve the dynamic response of system, according to the mathematical model of PWM power converter. Based the analysis of torque characteristics, analyze the maximum capturing principle of DFIG and make sure that it has the maximum power tracking performance. Finally, the complete modeling simulation of DFIG with grid is established in PSCAD. The simulation results show that the modeling simulation can realize the decoupled control of active and reactive power, and maximum power tracking, which verify the correctness and feasibility of model of DFIG.2. The maximum power tracking in wind is converted into a optimization problem. And QIEA is studied to optimize the maximum power tracking in wind power. There is always a unique maximum output power point when the speed of wind turbine changes in any time, through the analysis of wind energy conversion principle of wind turbine. It finds that the QIEA has the better global optimal quickly searching ability after studied the random searching algorithm. QIEA is analyzed to optimize the maximum power tracking of wind. The maximum power tracking in wind is converted into a optimization problem, which is optimized in QIEA. The QIEA is completed in MATLAB and the induction and the double-fed induction wind generators with grid are modeled in PSCAD. The simulation results prove the correctness of the method. The method, maximum power tracking based on QIEA, not only searches the optimal value of the controlled variables and directly controls and regulates it by its ability to quickly random searching, better dynamic tracking the current maximum output power of wind, but also simplifies the control structures based on the mathematical models.3. Based on QIEA calculation of reactive power compensating capacity in wind is proposed, through the study of method of optimization of reactive power compensation in DFIG with grid. QIEA is researched to optimize the reactive power compensation in wind power with grid. The method that wind generator power factor and terminal voltage are simultaneously taken into account in the objective function, the characteristics of reactive power and voltage in wind farm, can optimize the compensating capacity of reactive power in different wind speeds. The reactive compensating capacity of the IEEE14standard system containing wind farm is calculated based QIEA in MATLAB, and the results demonstrate that the method of based QIEA calculation of reactive power compensating capacity in wind farm is correct and effective.