Research On The Key Techniques Of Small Maglev Low Wind Speed Generator

The large-scale development of wind power is one of the most realistic strategies to solve the energy and power shortages in China. Wind rich and relatively rich areas in China account for just 26% of its territory. However, there needs to be a higher starting resistance of traditional wind generators. The wind speed for starting wind generators is 3.5m/s, and must be up to 4.2m/s for power generation. According to the existing wind power generation technology, the annual average wind speed needs to be no less than 5m/s for wind power plants. For most of less wind regions, it is difficult for wind generators to reach the power rating, due to the low annual average wind speed, small wind and variable wind directions, even though there is the auxiliary solar power generation. Therefore, it's important for extending the utilization area of wind energy to master the key technology of small low wind speed generators (e.g., blade, supporting and generator technologies). The key technology is also essential for development of low wind speed resources and raising its wind utilization efficiency.In the thesis, the magnetic suspension supporting technology is introduced to small low wind speed generators. The thesis focuses on how to improve the conversion efficiency of mechanical energy to electrical energy and how to reduce the mechanical consumption in the process of energy exchange. Meanwhile, the technologies of the blade design and the magnetic suspension supporting of the small maglev low wind speed generator are researched. The blade design technology is to make blade spin lightly; the magnetic suspension support technology is to reduce and even eliminate mechanical friction between bearings and shafts of wind generators. Therefore, the startup speed of the wind generator would be reduced.Based on the Bates theory, the thesis designs 500W small wind generators' blades and obtains the correlative design parameters. The force applied to rolling blades and wind wheel bearings is analyzed. Then, the three-dimensional model of small wind generator blades is built with Solidworks. The modal analysis of the model is done with finite element software - ANSYS. The natural frequency and vibration model of blades before five-order are calculated and analyzed.The small wind generator supporting technology is to reduce or eliminate friction between bearings and shafts, and thus the low wind speed startup of small wind generators is realized. Magnetic suspension supporting suspends rotors by using magnetic force. Compared with ordinary bearings, magnetic suspension supporting has lots of unique advantages, such as no mechanical contact, no friction, no wearing, no lubrication, and long lifetime. The thesis proposes magnetic bearings combining with mechanical bearings for supporting rotors. A magnetic permanent bearing is designed which axial superposed and magnetized in the axial direction. The structures of the small maglev low wind speed generator are designed, and the rings' bearing capacity is analyzed. The experiments show that magnetic bearings can satisfy the requirement of bearing capacity.