Research On Wind Turbine Variable Pitch System With High Accuracy Position Servo Control Technology

Wind energy, as a type of clean and renewable energy, becomes more and more important around the world. Moreover, wind power generation-the main type of wind energy utilization attracts interests of researchers from all countries. Variable pitch wind turbine has increasingly become the mainstream model of wind machines, with advantages of maximum wind energy collection, stable power output and such like that. Control technology on variable pitch is a key technology in megawatt-class wind turbine control. In this paper, we give comprehensive theoretical analysis, simulation and test verification on megawatt-class wind power unit electric variable pitch control.First of all, surveys on wind power unit working principle and corresponding control technology are listed, and main contents of this paper are given. Researches on variable pitch control processing were carried out, based on wind turbine blades aerodynamic analysis. Analysis on the function of variable pitch parts in different working stages and deduction of variable pitch control strategy are then proposed. In the end, theory on variable pitch wind turbine is vivificated and validated, through variable pitch wind turbine modeling and simulation.Secondly, electrical variable pitch executive structure is designed. Selection of main components is carried out through calculation of key parameters like blade driving force, based on which, research including control principal, executive structure design, control parameter adjustment, on independent variable pitch control system can be implemented. The result confirms the feasibility of independent variable pitch control strategy, and consolidates the research on multiple coordination and blade control.Finally, we propose a weight coefficient adjustment strategy on orientation angle based on virtual principal axis synchronization control, the main purpose of which is to overcome the drawbacks of traditional independent variable pitch control like high cost and poor coordination of multiple control signals. The strategy not only improves coherence and consistency of actions while multiple propellers change, but also optimizes control parameters including mutual distance and angle of blades in different spatial location. With it, a dynamic simulation model on independent variable pitch control system is established. We examine influence of test signals of typical position and make a explicit comparison and analysis, Further research is carried out on electrical variable blade distance of ground simulated platform. Virtual spindle synchronization control was studied through ground-based simulation test-bed. The simulation results showed that an independent variable pitch angle weights adjustment strategy can meet the wind-independent variable pitch control of the actual requirements. Theoretical analysis and experimental simulation realize accordance that actual demands of independent variable blade control can be satisfied, with the proposed weight coefficient adjustment.