Control And Simulation Of The Variable-speed Constant Frequency Wind Power Generation System Using SIMULINK/MATLAB

Control and simulation of the variable-speed constant-frequency (VSCF) wind power generation system is a complex cross-disciplinary systematic engineering, which needs in-depth understanding and analysis of aerodynamics, electric machinery, power electronics technology and computer digital control technology. In this paper, a comprehensive introduction has been given about the basic theories and composition of the VSCF wind power generation system, and a detailed description of the theory of electric machinery and power electronics especially the application of SVPWM into the wind power generation system is also exhibited. Using the popular mathematical models and formulas to simplify the complex aerodynamics, this paper gives a detailed simulation analysis of the operations of wind turbine in two kinds of actual operation conditions, which in order to obtain a concise and accurate understanding of the operation and control of the VSCF wind power generation system.This paper using the Simulink/Matlab as a tool for simulation, models the basic modules of the VSCF wind power generation system, including wind speed, wind turbine, drive train system and doubly-fed induction generator (DFIG) which models in a variety of coordinate systems and gives a detailed analysis and comprehensive summary. As a expanding application of mathematical model of the double-fed induction generator, this paper practice it into the diagnosis of induction machine and the voltage establish of the induction generator, which shows indirectly an accuracy and applicability of the models. As another key work, this paper has carried out a detailed simulation of operation control research of the VSCF wind power generation system. In this part, description of the basic principle of variable-speed constant-frequency is necessary. The operation regions and the corresponding operation strategy of the VSCF wind power generation system are also introduced. An emphasized analysis has been given about the speed control scheme which takes place below the rated wind speed and power control scheme which above the rated wind speed. In the part, the article shows the step response and the actual wind speed response in two kinds of operating conditions, which turns out a satisfied simulation results.In the mean time, based on the mathematical model of doubly-fed induction generator, grid-connect control strategy and generation control strategy of the VSCF wind power generation system has been introduced. In this part, key work lies on the simulation of the grid-connect control with no load, which deepens the understanding of the grid-connect control strategy. As for generation control, the decoupling control diagram of active and reactive power in stator winding of DFIG is given.Finally, this paper conducts an introduction of the structure and characteristics of the back to back dual PWM converter, which is the excitation converter of the VSCF wind power generation system, and describes the principles and control targets of the rotor-side PWM converter as well as grid-side PWM converter. Then Use the topology diagrams to establish mathematical models and the Simulink models, and using Simulink to carry out the SVPWM modulation methods.