以風洞實驗分析垂直軸風力機的磁滯效應

各種升力型風力發電系統普遍存在著操作過程的磁滯現象。本文針對垂直軸升力型風力發電機進行風洞實驗，使用監測系統監測實驗中電壓、電流、風速、轉速等參數值，來探討風力發電機磁滯效應的特性變化，以及此磁滯現象對風力發電機的輸出功率有何種影響。實驗結果顯示風力發電機對應磁滯現象的外部負載阻抗範圍會隨著環境風速的增加而縮小，其負載阻抗平均值也隨之減少，對應磁滯現象的電壓與電流範圍都風速隨著風速的增加而加大，而且對應磁滯現象的邊界電壓值與風速幾乎呈現線性關係。利用所得電壓與電流分析輸出功率，發現對應磁滯現象驟升與驟降邊界的輸出功率在低風(<4.5m/s)與高風速(>8.5m/s)下都很小約低於2W，同時風力發電機的最大輸出功率皆出現在磁滯現象範圍內，而且最大輸出功率點非常靠近磁滯現象的轉速驟降臨界點，尤其風速越低越貼近，指出風力機在低風速環境下的輸出控制必須更加精準與反應快速，以避免風力機出現突然停機。

關鍵字

磁滯現象；風力發電機轉速；外部負載阻抗

並列摘要

Hysteresis phenomenon during the operation process of lift-type wind turbines has been observed and proposed. In this study, method of wind tunnel experiments was applied to investigate the character and the range variation of hysteresis phenomenon described by the relationship between the angular speed of wind turbine and the resistance of external electricity loading. Data of output voltage average resistance also decreases with the increase of wind speed. Ranges of output voltages and currents related to hysteresis phenomenon expanded with the increase of wind speed. Voltage values on the boundaries of hysteresis range are found to be almost linearly propotional to wind speed. Analysis form measured voltages and currents show that the voltage differences related to the hysteresis boundaries are less than 2W under conditions of low wind speed (<4.5m/s) and high wind speed (>8.5m/s). It is noted that the maximum power points always locate inside the range of hysteresis phenomenon and nearby the boundary point of angular speed sudden decreasing especially for lower wind speed. It indicates more precise control is needed to maintain the wind turbine operations under low wind speed condition.