Research on variable speed constant frequency independent variable pitch technology based on semi physical simulation
Abstract: Based on the aerodynamic analysis of wind turbine, the variable pitch variable speed constant frequency control law is obtained, and the control algorithm of brushless doubly fed machine electromagnetic resistance torque regulation and segmented PID weight coefficient distribution is proposed to realize variable speed distribution and independent variable pitch control respectively. In the traditional control, pitch and variable speed constant frequency are bounded by the rated power. Due to the large inertia and hysteresis of the wind turbine system, the output power will fluctuate during the switching process of the two algorithms. Therefore, a comprehensive control algorithm bounded by the predicted power is proposed. The algorithm is based on the self built semi physical simulation test-bed with bladed software as the model and pitch and controller as the physical object. The accuracy is: 0.5 level for test analysis, The results show that the output power of the generator has been greatly stabilized
key words: variable speed constant frequency, independent variable pitch, weight coefficient, prediction, semi physical simulation
wind turbines using clean renewable wind energy has been highly valued all over the world With the increase of unit capacity and total installed capacity, the proportion in electricity is also increasing. In order to obtain high-quality wind power, the requirements for unit control are also increased accordingly. Theoretically, the wind turbine should convert all wind energy into electric energy as much as possible, but in fact, it is limited by the strength of some parts of the mechanical and electrical analysis instruments and electrical instruments of the unit, which also belong to this category. When the wind speed is higher than the rated value, it is necessary to maintain the output power of the important market concerned by the development of plastic utilization of generators around the rated power (variable pitch), and when the wind speed is lower than the rated value, Capture the maximum wind energy as much as possible through variable speed constant frequency technology. Variable speed constant frequency and variable pitch technology have become two key technologies of wind turbines [1]. At present, foreign scholars have carried out research, but often only focus on one aspect. In the whole control process of wind turbine, especially when the wind speed changes near the rated value, the two control technologies continue to switch. How to coordinate with each other has certain research significance for maximizing the capture of wind energy, stabilizing power output, and reducing abnormal mutations
the level of wind power in China is relatively backward. The self-developed wind turbine is only 750kW, with low cost and fixed pitch control. The State Key Laboratory of fluid transmission and control of Zhejiang University, supported by the national "863" program, began the research on variable pitch control technology, and carried out technical cooperation with other scientific research groups. Combined with the variable speed constant frequency technology currently studied, and based on aerodynamic analysis, the theoretical basis of variable speed constant frequency variable pitch control was obtained, The integrated control algorithm of the two technologies is studied on the semi physical simulation test-bed based on the international authoritative wind turbine design software bladed
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