Modeling of Wind Turbines of Integration Type and Its Networked Control Method Research
【作者基本信息】 东北大学， 控制理论与控制工程， 2011， 硕士
【Abstract】 As energy and environment crisis is becoming increasingly serious, energy saving and low-carbon are advocated worldwide. As renewable green energy, wind power is drawing growing attention and research enthusiasm from scientists and engineers all over the world.Wind generation is a comprehensive research area that involves aerodynamics, automatic control, mechanical engineering, electrical engineering, computer science and material science, etc. Nowadays, the research focus concentrates on large-scale wind turbines design, wind generation integration, low voltage ride through, advanced control scheme and optimization algorithms design of wind turbines. Progress in wind energy will have a significant promotion in development and innovation of information technology, energy, mechanical engineering, material science and power system, bringing economic and social profits for human beings and reducing carbon emission. Wind generation of integration type has its own advantage. It can transform wind energy to electric power and transfer electric power form the area that is has abundant wind energy to the area that of high demand of electric power. This thesis focused on wind generation of integration type and did research on the below aspects.1. The aerodynamic model of wind turbines was built. First, blade model was built based on blade element momentum theory, wind turbines stall phenomenon was explained by the model acquired. Second, wind speed model was got by utilizing statistical data, which brings convenience to simulation of wind turbines design. Finally, rigid and flexible transmission system model were derived that suited to different research focus.2. Electromagnetic model of wind turbines was built. The widely used doubly-fed induction generator was chosen as generator of wind turbines. To begin with, voltage and flux model of doubly-fed induction generator in three phase static framework and two phase synchronous framework were derived. With regard to the characteristic of doubly-fed induction generator, model acquired can be simplified via flux orientation. Furthermore, model of integration interface—bidirectional PWM converter was built. Compared with integration interface model in other literature, this thesis took dynamic behavior of DC section into account, which is an improvement.3. For high penetration of wind generation to modern power grid, wind generation played growing important role in power grid regulation. Aiming at this situation, this thesis put up with networked control method in wind integration operation of control and regulation originally. Networked model of wind generation is derived. For the down power regulation circumstance that power grid limited output of wind generation, networked robust controller was designed when the network induced delay is time-varying, uncertain and upper-bounded. The robust controller can be got via solving LMIs by Matlab. Effectiveness of the robust controlled was verified through numerical simulation.4. Integration model that took load model into account was built by analyzing the network of wind generation integration. From power system stability perspective, chaotic phenomenon which should be avoided in power system, was discovered when the injection power of wind generation was in a special region. The chaotic phenomenon in power system should be suppressed. However, as the integration model is strong coupling and nonlinear, it is difficult to design control law to control the complex nonlinear chaotic system. Meanwhile, as universal approximation precision of fuzzy hyperbolic model, this thesis used fuzzy hyperbolic model to approximate the complex chaotic integration system originally to simplify controller analysis and synthesis. Thus, control scheme can be designed based on intelligent control theory via system identification. The power injection of wind generation to ensure the power grid to operate safe and stable was derived, which was of practical value. Numerical simulation verified the designed control scheme.