近幾年電動機已成為最主要的動力來源。因為直流無刷馬達的簡單控制性與高效能的特性，因此在現今的工業界中直流無刷馬達應用相當的廣泛，例如：電動機車、壓縮機與家電產品…等。

在直流無刷馬達速度控制中，直流無刷馬達的轉子角度與速度是不可或缺的重要資訊。編碼器被廣泛地被用來做為馬達的速度感測器，但是編碼器的存在會提高整個系統的成本、體積與可靠度的問題。為了改善上述的問題，直流無刷馬達的無感測速度控制有其必要性。

本論文提出一個以轉子磁通為狀態變數的狀態觀測器應用於直流無刷馬達的無感測速度控制。利用直流無刷馬達於靜止軸的數學模型下，建立一個以轉子磁通為狀態變數的狀態方程式。本論文所提出的磁通狀態觀測器可估測直流無刷馬達的轉子角度與轉速；再經由角度與轉速估測搭配六步方波驅動法與脈波寬度調變技術以進行速度控制。本論文利用Lyapunov’s演算法來證明磁通狀態觀測器的收斂性與穩定性。最後透過模擬與實驗的結果來驗證本論文的目標。

Electrical machines have already become the major source of motive power in the present age. The brushless dc motors possess some advantages such as higher power density, higher efficiency, and simpler controllability. Hence synchronous ac motors become rather popular for many applications, such as compressors, automotive, and household products etc.

For the speed drive of a BLDC motor, information on rotor position is indispensable. However, mounting a position sensor on the rotor causes several drawbacks from the viewpoints of reliability, cost, size, and cable wiring. In order to cope with these drawbacks, a number of sensorless control methods have been proposed so far. In the last two decades, several approaches on sensorless control for BLDC motor have been proposed and developed.

This thesis proposes a sensorless control method using a rotor flux state observer to estimate rotor position and speed estimator. In the proposed rotor flux state observer, the flux due to rotor magnet is chosen as the state variable, and the rotor position and speed could be estimated. The Lyapunov stability theorem is used to prove the rotor flux state observer system is stable. Finally, simulated and experimental results are presented and verify the proposed sensorless method is feasible.

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