基於反電勢無角度感測器控制之基礎問題與改善

Abstract

本論文針對非凸極型永磁馬達的無感測器控制，提出一系列延伸可用轉速域的方法。本文將分別就低速以及高速兩方面，分析造成系統可控制性降低的關鍵感測問題。為了徹底處理電壓源變頻器所引入的非線性，首先提出一種量測脈寬調變相電壓之高頻寬量測方法；經由這種量測方式得到的相電壓具有高解析度，可用於增進反電動勢無感測器控制於低速的估測準確度。為了更進一步的改善反電勢無感測器控制在低速時對負載響應強韌度不足的問題，再提出基於磁通電壓模型進行無感測器控制的方法。而在提升高速極限方面，首先推導出馬達反電勢估測的數位化模型，以此評估不同角度估測方法的動態範圍，再一併整合進所提出的高速數位化估測器中，達到增加系統於低採樣點數時的穩定性以及動態性能之效果。為了驗證上述演算法相較於主流估測方法之改善，文中也提出可供參考之相關實驗結果；且這些演算法具備了整合成全轉速域通用方法的潛力，將可用於延伸表面貼磁式永磁馬達的操作轉速域。更重要的是，所有提出的方法都能以合理的成本實現於實務應用中。

This research provides a series of approaches on extending the utilizable speed region for non-salient motor position sensorless drives. Key position sensing issues casuing the degradation on controllability have been analyzed at both low-speed and high-speed. To substantially conquer voltage-source inverter nonlinearities, a high-bandwidth PWM voltage measurement technique has been developed. It can be applied to increase the low-speed EMF estimation accuracy. Furthermore, in order to improve the insufficient stiffness of EMF-based drive at low-speed, a modified voltage-model flux-based position estimation is proposed. For high-speed sensorless operation, a novel discretized estimation is derived to enhance the stability and dynamic response for the controller with low-sampling point condition. Each algorithm has been compared with existing solutions to ensure the improvement on position sensorless drives. These algorithms are capable to integrate into a single scheme to extend operating region of surface permanent magent (PM) machine drives. More importantly, all proposed methods can be realized in practical way with reasonable cost.