Study On Controlling And Modeling Of Double-fed Induction Generator

Wind energy as a green renewable energy attaches great importance to the world. Windpower technology has become the world’s fastest growing, most mature production of cleanenergy technology. Doubly-fed wind turbine because of its high energy conversionefficiency, high reliability and security, and network power control flexibility and manyother advantages, has become the mainstream model for wind power development. Asincreasing of the wind turbine installed capacity，the fluctuation and intermittent of windpower will affect electric network security and stability greatly. There is importantsignificance to establish a suitable equivalent model of wind farm. Aiming at double-fedinduction generator, in-depth study focusing on modeling, control strategy of the DFIG andthe equivalent modeling of wind farms. The main contents can be summarized as follows:First, the background and significance of the research, Overview of the development ofwind power at home and abroad and wind power control technology; given the role of thebasic structure of the doubly-fed wind turbine and energy under the operating principle anddifferent operating conditions flow.Secondly, the introduction of coordinate transform thinking, detailed derivation of themathematical model of the three-phase stationary coordinate system of double-fed windturbine and synchronous rotating coordinate system.，laid the theoretical foundation for themodeling of DFIG. Elaborated on the operating characteristics of the wind turbine, themaximum power point tracking principle, and pitched angle control system.Third, around the rotor side and network-side converter control strategy to expandresearch. Rotor-side converter control system design, the stator flux oriented vector controltechnology to achieve active power and reactive power decoupling, the maximum windenergy capture control objectives. For the network side converter control system design, gridvoltage oriented vector control technology to maintain control of the DC side bus voltagestability and unity power factor running target. Fourth, the in RSCAD simulation environment, the establishment of a complete double-fed wind power generation simulation system, including the wind turbine model, the doubly-fed generator model, dual PWM converter model, control system model and SVPWMmodule. In-depth study of the doubly-fed wind turbine and grid transient characteristics ofthe dynamic characteristics of grid failure, the causes of various phenomena. And thecorrectness of each part of the mathematical model of the doubly-fed wind turbineestablished the validity of the corresponding control strategy is verified by simulation.Fifth, based on poly legally established the equivalent model of the doubly-fed windturbine wind farm, the constant wind speed and the operating characteristics of the windfarm grid three-phase short circuit fault conditions. The simulation results contrast verify therationality and effectiveness of equating methods used.