Research On Design Principle Of Speed Self-stabilized Transmission System For Wind Turbine

Nowadays,the utilization of energy tends to be diversified and clean.Grid-connected wind power is growing rapidly as a promising form of renewable energy.Most grid-connected wind turbines operate at variable speed and constant frequency(VSCF).The wind rotor is driven by random wind,and use an inverter to obtain power synchronized to the grid frequency at the end of the transmission system.Current mainstream wind turbines use synchronous or asynchronous generators for electricity,and connect to the grid using frequency converters and other electronic equipments.With the increasing of unit capacity,these operation model expose many problems.In view of the influence of frequency converters on wind power system,a speed self-stabilized transmission system for grid-connected wind turbines is proposed in this paper.A differential gear train is designed specially based on mechanism theory to output constant speed and achieve VSCF without frequency converters.First,based on the differential gear train with 'double-input,single-output'characteristic,this paper proposes the transmission scheme of speed self-stabilized wind power system.Through structural design and parameter selection,the system is able to output constant-frequency power to the grid under the condition of varying wind speed,without signal processing device and complex controller.Second,the rotational speed relationship and the power coupling characteristics of the basic components of the differential gear train are studied to determine the best arrangement of basic components.Then,the power flow and efficiency of the differential gear train is studied,and its structure design and parameter optimization are carried out,which provides technical scheme for the design and development of new grid-friendly wind turbines.Finally,a semi-physical experiment rig of speed self-stabilized transmission system for grid-connected wind turbine is bulit,and the principle and feasibility of the system is studied and verified through transmission experiments.Use wind speed model obtained by FAST software as input of the system and investigate the output characteristics of the transmission system under the conditions of the general wind and the load fluctuation of the grid.Through the comparison of the measured speed data and the ideal value,the validity of the transmission system of the speed self-stabilized transmission system for grid-connected wind turbine is verified.