垂直軸風力葉片效率提升與發電機匹配研究

Abstract

本研究主要探討改變垂直式升力型風力葉片裝置角來提升風力葉片效率，降低發電機頓轉扭矩提高葉片啟動性。透過垂直軸升力型理論計算不同裝置角產生之效率，選擇效率較佳之裝置角來調整，由凸輪概念設計可調裝置角機構並實際製作成品。改變發電機槽極的比例與磁鐵展開角降低頓轉扭矩，使用有限元素軟體模擬並討論槽極比例與展開角對頓轉扭矩之影響。說明如何透過抽載模擬分析將葉輪操作在最佳效率工作點提升風能利用率，比較發電機不同槽內匝數對匹配之影響。最後，比較不同發電機槽內匝數與電池系統對發電機切入轉速之影響。

The purpose of this thesis is to develop a device for adjusting the pitch angles of the wind blades and reduce cogging torque of a permanent magnet generator so that the efficiency of the vertical-axis wind turbine (VAWT) can be increased. We calculate the efficiencies of the VAWT for different pitch angles. The pitch angle that can produce the best efficiency of the VAWT is then used to design the pitch angle adjusting device which is a cam type mechanism. To start rotation at a lower wind speed, we utilize the advantages of resisting type wind blades for the wind turbine. At the central part of the VAWT, two C-shape resisting blades are used to generate torque at low wind speed while at the outer part, two vertical wind blades of airfoil shape are used to produce torque at mid-to-high wind speed. A wind direction tracking mechanism is developed to adjust the pitch angles of the wind blades according to wind direction. In reducing the cogging torque of a permanent magnet generator, the slot/pole ratio and magnet spread angle are calculate to choose the proper values for the design of the generator. The maximum power point tracking curve is also determined for the future design of the control module.