本文主要的目的是實現無刷直流馬達(BLDCM)無轉軸偵測元件之驅動系統。無刷直流馬達具有高轉矩、高效率等良好特性，由於沒有整流子及碳刷，擁有可高速運轉且避免維修等優點。本文中發展無轉軸偵測元件驅動系統以取代霍爾元件與光編碼器等感測器，以增加系統的強健性與達到降低成本的優勢。 整個架構以數位訊號處理器(DSP)為中心，藉由電動機之反電動勢(Back EMF)偵測出轉子磁極所在位置，以提供換相訊號及完成轉速估測，再以此轉速估測值建立閉迴路之轉速控制系統。在訊號估測方面，使用鎖相迴路(PLL)將偵測到的反電動勢訊號相移90度，配合外部偵測電路及內部DSP程式的撰寫以獲得轉軸位置資訊，提供換相時所需之訊號，此法亦使無刷直流馬達可控制之轉速範圍加大了。而從靜止到啟動的問題，仍是無轉軸偵測元件驅動系統的一大主題，文中也將針對這一部份加以說明。此外，我們使用了模糊控制器(Fuzzy Controller)來控制馬達的轉速，使其能夠順利追踨轉速命令達到所要的控制效果，最後並以實驗數據及圖形加以驗證本論文方法之可行性。 The purpose of this thesis is to design a sensorless drive system of Brushless DC Motor. Due to no rectifier and brushes, it has the characteristic of higher torque and higher efficiency. The advantage of the motor is that it could run in the high speed and no need to maintain it. Such position sensor, like Hall-effect sensor, may be eliminated to improve reliability and reduce cost. This thesis developed a no shaft detecting drive system to replace optical shaft encoder and Hall-effect sensors. The kernel of whole system is developed by DSP (Digital Signal Processor). The sensorless control method uses the sensed back-EMF (Back-Electromotive Force) to estimate rotor position; it provided the motor with commutation signal, and we could create a velocity control system from it. A PLL (Phase-Lock Loop) technique is employed to estimate the position signal, 90o phase shifting the zero-crossing points detected from back-EMF. It made the system operate in wide speed range by the outside PLL detecting circuit and inner program controlling. Besides, from standstill to start-up is still an important issue in the sensorless control system of Brushless DC Motor. Furthermore, this thesis used fuzzy theory to control the speed of Brushless DC Motor; it shows a good performance to our control system. Finally, the proposed scheme has been successfully verified by analytical and experimental results.
