基於無感測器無刷直流馬達之參數鑑別

Abstract

無刷直流馬達因具有高效率轉換、高可靠性及免維護性等優勢，加上近年來極力推動節能減碳的政策，因此被廣泛的應用在日常生活中、工業場合等。一般無刷直流馬達需要仰賴霍爾元件(Hall sensor)來偵測轉子位置使無刷直流馬達換相運轉，但由於霍爾元件在高溫場合容易失效，且近年來講求小空間、大效率與低成本等，故無感測器無刷直流馬達的控制方法慢慢成為主流。

本文是基於離線作業下(Off-line)的無感測器無刷直流馬達的參數鑑別，乃利用線電壓和法搭配積分在特定區域中估測出馬達的反電動勢常數及偵測無感測器無刷直流馬達的反電動勢零交越點(zero crossing point)；其用來判斷無感測器無刷直流馬達的正確換相時機點，再利用變頻器開關切換的情形來推導出其在導通時、截止時的馬達電壓與電流物理式，並用推導後的結果式來估測在高頻切換時的馬達電阻值、電感值，再應用頻率響應的概念於速度迴路下估測出轉動慣性矩與摩擦係數。

Brushless DC motors(BLDCM) were extensively used in recent years due to the effort from government of promoting energy conservation and reducing carbon footprint. Also, it has the advantage of high efficiency and high reliability. In general, BLDCM relies on the Hall Effect sensors to detect the rotor position. However, in some extremely working environments, the Hall sensors are not suitable to be applied. Furthermore, in some in dustrial applications, the pursuit of small size, high efficiency, and minimum cost are the major concerns. For these reasons, the sensorless drive for BLDCM becomes the main trend. This thesis proposed the parameter identification for the sensorless BLDCM. Line to line voltage addition and integration methods are used in this thesis to estimate the back-electromotive force (Back-EMF) constant and to detect the Back-EMF zero crossing points for commutation.Deduced formulas are used to solve the current equations during PWM ON and OFF period. Thus, the resistance and the inductance of the sensorless BLDCM cab be identified. And we used the concept of frequency response in the velocity feedback control looped to estimate the inertia moment and friction coefficient of the BLDCM.