Research On The Operating Control Strategies Of The Variable Speed Variable Pith Wind Turbine

The paper analyzed some basic running control strategy of the wind turbines, andon this basis for the wind turbine tower before-after vibration, drive train torsionvibration, the optimal pitch angle to capture maximum wind is difficult to determine dueto changes in blade shape, quality and simulation error on the optimal control stage androtor running too fast, the overload of the key parts when the wind turbine is in gustload case.The paper built a5MW wind turbine model and as an object of study, based on theFAST software which is used to design and calculate wind turbine load as well asMATLAB/simulink software, the paper made a simulation analysis. The simulationverified the effectiveness of the proposed control algorithm.In the thesis, the major work and tasks are summarized as follows:Chapter1: Introduction. This chapter introduced the research background andelaborated the status and trends of wind power technology research.Chapter2: Building a wind turbine model. Based on the FAST software built a5MW wind turbine model which can be a basis for follow-up simulation andverification of the control algorithmChapter3: The operation control principle of the variable speed variable pitch windturbine. Analyzed the basic operation control strategy of the variable speed variablepitch wind turbine, including torque control, pitch control and the division andswitching methods of different control stages.Chapter4: Wind turbine controller design based on the FAST and MATLAB/Simulink software. This chapter made a linear analysis of wind turbine model, andobtained the PI parameters of wind turbine pitch and pitch angle gain coefficient atdifferent wind speeds. The simulation results showed that the obtained parameters canwell meet design requirements. For the wind turbine itself had very small damping andtower vibration during operation, this chapter study the problems of the tower b-fvibration and s-s vibration, and established the simulation model in Simulink software.The simulation results showed that the control method can effectively reduce the b-f ands-s bending moment of tower base.Chapter5: Adaptive pitch control strategy of variable speed variable pitch windturbine. Analysis of the wind turbine control objectives below the rated wind speed was made and pointed out that the lack of many methods to determine the optimal pitchangle. Taking into account the inaccuracies and changes of wind turbine installation,manufacturing as well as the operation parameters, proposed a adaptive pitch controltechnology based on a discrete hill-climbing algorithm. Made a co-simulation inSIMULINK software with FAST, the results showed that the proposed adaptive controlstrategies pitch could track the changes of optimal pitch angle and make theaerodynamic efficiency optimal of the wind turbine.Chapter6: Controller design based on of the state space technology. In this paper,using the method of modern control theory, combined with the linear quadratic regulator(LQR), designed a collective pitch controller, generator torque controller andindependent pitch controller based on state observer and disturbance adaptive controltechnology. Simulation in Simulink software with FAST was made, and the resultsshowed that the designed controller could reduce the drive train torsion load varyingdegrees as well as reduce the fluctuations of the rotor speed so that the electrical poweroutput was stabilized.