Modelling and control of the doubly-fed induction generator

Currently, mankind is faced with two pressing issues about energy and environment, therefore the use of renewable, green energy-wind energy, hydropower and solar energy as an important clean alternative energy is extensively spread which has a great significant effect over the world in recent years. Among these renewable energies, the unique advantages of wind energy draw much attention from scholars of various countries. Wind power technology has become a hot research topic. And the research about the control of wind power systems has become a hot topic. In this regard, people in the world are devoted to develop the technical innovation. Among all these technologies, wind power system of variable speed fixed frequency is most widely used, especially in the use of wound asynchronous motor as doubly-fed machine. Based on this system, the back-to-back AC frequency converter is controlled by the control system to realize the utilization of maximum wind power in the wind energy conversion system with doubly-fed induction generator. In this dissertation, the current development situation of wind power generation and dual-PWM converters is introduced. Then a brief analysis of the basic principles of wind power generation system is discussed. To control the doubly-fed induction generator, the PWM converters are analysed. And the proper control method is chosen. Finally, in the Matlab/Simulink platform for the software simulation, and simulation results verify the rotor side converter can achieve decoupling of P and Q; grid side converter can achieve unity power factor rectifier and DC side voltage stability functions.Master of Science (Power Engineering