Modeling Of A Controlled Doubly Fed Induction Generator For The Use In Offshore Wind Power Plants

China has huge offshore wind resource potential, and the marine wind power will be the most important growth point of wind power industry in the future. After a brief overview of the actual state of the use of offshore wind both in international and domestic, and the state of the art of wind power technology, this paper focuses on the exploiture of offshore wind plants and simulation of its generator system.The first part is about the offshore wind plant. In this part, the advantage and major challenges of developing marine wind power are explained, and key steps are listed, including preparatory work, site selection, support structure design, and integration to the grid. Then, primary design of the offshore wind power generator system are discussed, which consists of design of wind turbine and selection of driving technique from wind turbine to generator. It comes to a conclusion that a favorite generator system for such offshore application is the Doubly-Fed Induction Generator(DFIG),due to its advantage in weight and operation.The second part of this paper is the simulation of DFIG wind power system. The mathematical models of DFIG system are built, including random wind speed model, variable speed constant frequency(VSCF) wind turbine model, DFIG model based on different reference frame. Furthermore, a state-space-equation-model of the DFIG in field oriented coordinates is derived and discussed. This coordinate system offers the possibility of decoupled control of active and reactive power. The structure of the control loops are presented. At last, the whole system model is founded by the software Matlab/Simulink. The result of experiment approves that the control strategy is true. Not only the frequency of stator current is constant, but also the control of stator active and reactive is decoupled, and realizes the track of the maximal power of wind turbine.