| Since wind energy possess great randomness, intermittence and fluctuation, wind energy field still has various problems need to be solved. Control system, servers as the brain of wind turbine generator system (WTGS) for safe operation, plays a pivotal role in wind energy capture maximization, system fatigue load reduction, service life extension and etc. Meanwhile, it is one of the key factors for WTGS localization. The work of the dissertation is under the support of The Key Technology of Wind Turbine System Design, Chongqing Key Scientific and Technological Project (Project Number: CSTC2007AB3052). The dissertation conducted in-depth research of WTGS in overall modeling, control strategy optimization, control algorithm design, experimental platform setup and etc. The structural layout of the dissertation is summarized as follows:Chapter 1 described worldwide development tendency of wind power technology, discussed the opportunities and risks the wind industry in China has been facing, pointed out the research status and existent problems of WTGS control system, and delivered main content and structure of the dissertation.Chapter 2 investigated the entire model of WTGS facing control system design. Based on‘‘module’design concept, divided WTGS into aerodynamics, mechanics, electrics and pitch system four main functional modules, and introduced their working principles and operating characteristics in great detail. Specifically aiming pitch system, proposed applying different pitch rate limit and dynamic wake compensation mechanism to eliminate the influence of unfavorable factors, such as big inertia and delay.Chapter 3 forwarded a synthetic performance optimization control strategy. Its main design methodology is to adjust pitch angle in small range before approaching nominal operating point, meanwhile, coordinate with closed-loop torque control to enhance system controllability at nominal operating point and to reduce power fluctuation and transient load jump range, targeted to find balance between maximum wind energy capture and minimum mechanical load.Chapter 4 devised the three controller’s smooth transition scheme to fulfill optimum tracking of synthetic performance optimized control strategy. Due to the time-varying, nonlinearity and strong coupling features of the transition region, traditional control methods cannot meet system static and dynamic performance benchmark. The control method, which is based on fuzzy neural network, can be independent of target accurate mathematic model and prevent time-varying, parametric perturbation and other factors. On the basis of fussy controller, an algorithm which can online adjust fuzzy control request form by using single neuron is presented. Applying the algorithm to simulate a 1.5MW variable-speed variable-pitch WTGS validated suggested control strategy and control algorithm and shows it is a feasible method for WTGS overall performance optimization.Chapter 5, according to wind tunnel design principle, using axial flow fans as original power and self-made wind duct as tunnel, established open type wind tunnel. The wind tunnel is to realize flexible connection between wind and wind turbine and create more realistic wind turbine operation circumstances. Furthermore, a wind turbine experimental platform has been setup based on hardware-in-the-loop simulation technology design method. To satisfy the tracking requirement for maximum wind turbine power output, the hardware and software structure have been designed as well. Through comparison between simulation and experiment, the results revealed: Designed control system can effectively track the maximum power, and thereby the established experimental platform is reliable and feasible.Chapter 6 summarized the dissertation and prospected for the future research work. |
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