本論文為針對無刷直流馬達無位置感測元件驅動器設計與實現，基於馬達線電壓與反電動勢零交越點之關係，建立換相訊號估測電路取代位置感測器以提供馬達轉子位置資訊。此外為強化馬達開迴路啟動之可靠性，本文提出藉由馬達啟動前之定位步驟，基於轉子磁通會影響定子線圈電感值，並間接影響定子線圈電流在定位期間暫態時之電流曲線變化，因此利用偵測電流變化以判斷馬達掛接負載輕重程度，並輔以模糊理論調整馬達啟動時之施力大小，藉以達成在每次馬達啟動之初，啟動之可靠性與避免啟動電流過大之問題。In this thesis, design and implement for sensorless brushless dc motor drive are discussed. Based on the relationship between line to line voltage and zero crossing points of back electromotive force in motors, hall signal estimation circuit is established to replace hall effect elements which provide the information of the rotor position. Furthermore, to enhance the reliability of open-loop start-up procedure, a duty adjustment strategy is proposed in this thesis. Based on the phenomenon of the inductance change in stator winding which is affected by the rotor flux linkage, the time which dc bus current rises to the setting value is recorded during the aligned procedure before motor starting up. The rising time to the setting current level is used to estimate the corresponding load that the motor connects. Finally, fuzzy theory is introduced to calculate the appropriate start-up duty value for achieving starting successfully within different loads.
