水力發電是利用河流、湖泊及水庫等具有位能及動能的水流轉換成水輪機的動能，水輪機再將能量轉動發電機使機械能轉為電能。故水力發電是將水的位能或動能轉變為機械能，再轉變為電能的過程。
常見水力發電之水輪機中，主要可分為卡普蘭式水輪機(Kaplan turbine)以及佩爾托式水輪機(Pelton turbine)，其中卡普蘭式較適合低水位落差，且效率較為高。本研究之目的在於研製一小型水力發電系統，以最少的水量帶動水輪機葉片使發電機發電，以最環保之型態使用生活中一些可再利用之能源，運用於照明設備等各項電器用品，可安裝於高低水位落差的地形環境，例如:都市高樓排水系統等。
研究主要分兩個部分，分別為發電機構本體設計及葉片外型設計。發電機構本體設計部分則參考永磁式發電機的結構，設計一雙層磁石轉子以及中央線圈定子，使發電機在有限的空間下發電效率能提升，而能於最小流量下發電。葉片外型設計的部分則先透過速度三角形理論並配合田口方法，進行葉片之設計，接著利用數值模擬軟體以及實驗找出較高性能之葉片外型。
本研究使用田口實驗設計的L18直交表作實驗，依葉片數量、葉片角度及輪轂直徑作為控制因子，三水準，並定義發電電壓為品質特性，其理想機能採取望大作為指標，依實驗的結果找出能使發電機達到最大機電轉換效率的原始葉片設計，並比較在不同流量時各組葉片之發電量，觀察分別不同流量時適用之葉片組合。
透過數值模擬及配合田口實驗，依葉片數量、葉片角度及輪轂直徑作為控制因子，並使用L18直交表作為實驗的最佳分析組合結果可知：葉片數量多之葉片會有阻流之現象，故葉片數量6片適中，葉片角度適中的葉形具有較佳之發電效率，葉片角度較大之葉片的漏流現象較嚴重。本研究中經由田口分析機電轉換效率較佳之葉片，流量為4 m^3⁄hr，會有最大之發電功率1.44W左右，機電轉換效率為52.1%。

Turbines are widely used in hydropower generators and can be typically categorized into Pelton and Kaplan types. Kaplan turbines are usually used in low water head applications and are more efficient than the other type. In this thesis, a small hydraulic power generator of Kaplan type for driving LEDs is designed, implemented and tested. I hope the generator can be environmental friendly and reuse wastewater. The turbines are designed based on the theory of velocity triangle, and then the efficiency is examined by simulations and experiments. From the principle of the generator, a generator using permanent magnets with a small and simple structure and easy to carry is developed.
The results show that the optimized blade with special blade angle performs better whereas the leakage flow with a larger blade twist angle is more serious. The design of six blades is better than other blade numbers by the Taguchi Method. The test result shows that at the flow rate of 4 m3/hr, the rotation speed of the blades reaches 1200 rpm with the maximum power of 1.44 W, and the total efficiency of 52.1%.

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