一般家用小型風力發電系統採用永磁式同步發電機，與感應機不同於不需增加額外的輔助電源，並可在轉速較大範圍變動下輸出功率。市面上前端轉換器的轉換方式以二極體組成之橋式整流連接直流/直流轉換器居多，除了功率因數不高之外，更產生嚴重電流諧波失真使功率因數降低，同時發電機的電流諧波會影響發電機轉矩徑向力不均，造成機械應力與噪音。
本論文內容要旨以主動式前端轉換器並採用預測型電流控制於小型風力發電系統，在輸入電壓與頻率變動範圍以分階段直流電壓輸出方式轉換，達到改善之目的。主動式前端轉換器具有完全控制之優點，此外，預測型電流控制的動態響應快速，在追蹤電流上獲得精準的追蹤特性，並配合同步旋轉框之回授控制，可對頻率與相位做最佳化追蹤。本文針對主動式前端轉換器控制原理以及分段電壓方式進行說明，並模擬響應結果，分析靜態與動態之特性。建立主動式前端轉換器電路實體架構，以300瓦特與3仟瓦特之小型風力發電機測試，驗證噪音、功率因數與諧波電流的改善。

Wind power systems in household applications adopt permanent-magnet synchronous generator, different from the induction generators powered by auxiliary power, for delivery of electric power under variable wind speeds. In the market, most front-end converters consisting of bridge rectifiers in series with a DC / DC converter exhibit poor power factor inherent with serious current harmonic distortion. In wind power systems, harmonic currents generate unbalanced load torque results in mechanical stress and vibrational noises.
The objective of the thesis is to establish active front-end converter by using predictive current control in small wind power systems; the range of output voltage is set in several levels based upon input voltage and frequency so that current harmonics are reduced. The advantages of the controller are complete control, predictive control in current and fast response in tracking of the current accurately. In the controller, rotating synchronous reference frame of feedback control in frequency and phase can provide symmetric tracking structure. First, simulations in circuit are employed for analyzing the static and dynamic characteristics. Finally, 300W and 3kW rated small wind turbines are experimentally established for verification in improvement of vibrational noises, power factor, and current harmonics.

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