切換式磁阻馬達構造簡單、成本低且效能高，廣泛應用於各種產品。切換式磁阻馬達運轉時通常採用轉軸感測元件偵測換相位置，但其成本高且可靠度低，不適用於惡劣環境，因此發展出多種無轉軸偵測元件之控制方法。而大部分的無轉軸偵測元件控制法僅適用於低速區或高速區，能兼顧高速區與低速區的方法又需採用較強大的微處理器，增加系統成本。故本文探討切換式磁阻馬達在不同轉速下，結合兩種無轉軸偵測元件控制技術，期望以低成本的控制技術取代轉軸角度偵測元件。當切換式磁阻馬達在低速運轉時，其反電動勢很小，導通電流可做脈寬調變控制，利用偵測導通相之截波電流斜率以估測轉子換相位置；當切換式磁阻馬達在高速運轉時，反電動勢增大，導通相電流為單脈波形式，利用偵測導通相之磁通鏈以估測轉子換相位置。控制系統以微處理器配合硬體將之實現，並由實驗結果驗證本文所採用方法之可行性。

Abstract
Because of simple structure, low cost and high performance, switched reluctance motor have been applied widely various products. Switched reluctance motor drive usually employs position sensors to determine the commutation position. However, position sensors increase the cost and reduce the reliability of the drive system in harsh environments. Therefore, various sensorless control techniques are developed. Most of the sensorless control techniques are suitable only for high or low speed range. Some techniques which are suitable both for high and low speed range have to employ powerful micro-processer and increase the cost. This thesis combines two sensorless control techniques for switched reluctance motor in various speed ranges, so as to replace position sensors. When switched reluctance motor is operated in low-speed, the drive system is controlled by pulse width modulation technique because of low back electromotive force. Thus, the commutation position can be determined by detecting the slope of chopping current waveform of the excited phase. When switched reluctance motor is operated in high-speed, the excited current is single pulse mode because of high electromotive force. Therefore, the commutation position can be determined by detecting the flux linkage of the excited phase. This control system is sucessfully built with a digital micro-processer, and the experimental results are used to verify the feasibility of the proposed methods.

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