Study On Hydrodynamic Mechanical Variable Speed Equipment With Adjustable Guide Vanes In Wind Turine

With the rapid development of the society, the human is becoming more and more dependent on the energy. Because the traditional energy is constituted by the hydrocarbon and other mineral fuels,it has brought a series of issues,such as environmental destruction, the shortage of resources and so on,and it has obstructed the sustainable development of human society. All over the world, the wind energy has been an important component of the new energy resources.The wind energy is the green energy which is renewable and non-polluting, so it has got attention from the governments around the world. The world has come to an agreement on the development of the wind energy. However, the instability problem of the wind energy has been difficult to solve. The speed and torque will be changed with the wind in the spindle. This change delivered to the generator through the transmission system, results in the instability of voltage and frequency. It is a very important issue to change the wind into a stable available power in the field of wind power. There are two ways of solving the problem of frequency instability recently. One is the constant speed constant frequency generating system. But it has been gradually eliminated due to the inefficiency of using wind energy. The other is a variable speed constant frequency generating system. Due to the increasing capacity of the wind turbine, the electronic devices become increasingly complex and costly,and the reliability will be reduced.In this study, a hydrodynamic variable speed system with planetary gear drives and a hydrodynamic adjustable torque converter are proposed. It is a new variable speed constant frequency technology which can achieve variable speed input and constant speed output, so it get the frequency stability of the power. This paper provides a new approach for the efficient high-power transmission of the wind turbine, it is meaningful to the theory and engineering application. The adjustable guide vane of the torque converter is studied based on the new variable speed system. The main research work is as follow:(1) A new variable speed system is designed by studying the existing hydrodynamic variable speed system. The power flow of the system is calculated by the planetary theory and the node method. The mathematical models of wind turbine blade and the system are established to get the rule of the variation of the adjustable guide vane. The operating characteristics of the variable speed system is studied in the program clearly. The efficiency of the variable speed system is affected by the performance of the torque converter, and it lays the foundation for designing a new hydrodynamic adjustable torque converter.(2) The structure and the circulatory circle of the torque converter are set by analyzing the existing ones. The new hydrodynamic torque converter is devised, actually the program is used to design the pump, the CAD software is used to design turbine and stator.The structure of adjustable device of the stator is studied.The blades and the adjustable device are assembled to get the three-dimensional model of the adjustable torque converter.(3) The performance of torque converter with the variational guide vanes is analyzed by using the numerical simulation of the torque converter flow field. The flow field of the torque converter with different angles of the stator is simulated in different conditions in CFD software. Based on the numerical solution, the performances of the torque converter are predicted. The prediction can help to optimize the structure of the adjustable device and predict the performance of variable speed system. The regulation of the changing torque in the adjustable devices with the wind is studied to get ready for the control system. The methods of improving the hydrodynamic adjustable torque converter are proposed to satisfy the wind turbine.(4) As soon as the performances of the hydrodynamic adjustable torque converter is figured out, the mathematical model is established. The regulation of changing guide vanes is obtained with the mathematical model of the variable speed system. Based on the simulation of the torque converter and the variable speed system in simulation software, the output characteristics of the transmission system is analyzed.In summary, the paper designs a new variable speed system and a new hydrodynamic adjustable torque converter to achieve constant output speed in wind turbine. Through the simulation and mathematical modeling of the torque converter, the way of changing the guide vanes is got and the rated efficiency of the system is 94.8%. The system meets the needs of the wind turbine.The result of the research is very valuable to design the new hydrodynamic variable speed system and gets ready for developing the control system.