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標題: | 表貼式永磁無刷直流馬達齒槽轉矩削弱與設計優化 The Study for Reducing Cogging Torque and Design Optimization in Surface Mounted Brushless DC Permanent Magnet Motor |
作者: | Wei-Shun Chen 陳維舜 |
指導教授: | 劉志文 |
關鍵字: | 無刷直流馬達,齒槽轉矩,有限元分析,轉矩脈動, BLDCM,Cogging torque,Finite Element Analysis,Torque ripple, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 無刷直流馬達時永磁式同步電機的一種,英文簡稱BLDCM。與有刷直流馬達的不同之處在於,無刷直流馬達可以不使用機械電刷裝置,以霍爾感測器去取代碳刷換向器,以釹鐵硼作為轉子的永磁體材料。其性能上相較比傳統直流馬達有很大優勢,比如:体积小、重量轻;中、低速轉矩性能好,啟動電流小;無級調速,調速範圍廣,超載能力強;效率高,馬達本身沒有勵磁損耗和碳刷損耗。所以說,無刷直流馬達是目前最理想的電機。雖然無刷直流馬達具有諸多優點,但仍存在一些影響其性能的問題,其中一種就是齒槽轉矩。由於電機本身的齒槽物理結構會不可避免的在馬達中產生一種轉矩,即是永磁電機繞組不通電時永磁體和定子鐵心之間相互作用產生的轉矩,這就是齒槽轉矩。齒槽轉矩會使馬達出現轉矩波動,導致振動和雜訊的產生,使馬達不能平穩運行,影響其的性能輸出。因此,本文核心為削弱齒槽轉矩。研究方法大致如下:
使用傅立葉分解推導和能量法得到的齒槽轉矩表達式為基礎,分析了馬達極數和槽數的配合、磁極的極弧係數、定子槽之槽口寬度等一些設計參數對馬達齒槽轉矩的影響。並且推導他們在馬達參數設計優化中的計算方法。同時,對通過優化磁極削弱齒槽矩的方法,如不等厚永磁體和磁極偏移的方法進行了研究。 最後先後運用極數和槽數的配合、極弧係數、槽口寬度、磁極偏移、偏心距以及磁極偏移的方法應用於一台電動車上使用的1200w無刷直流馬達。對齒槽轉矩以及其性能進行模擬實驗。通過對馬達空載時氣隙磁密跟反電動勢的分析,以及負載時輸出轉矩和馬達A相電流的研究,找到削弱本馬達齒槽轉矩的最優參數。 The brushless dc motor, or BLDCM, is one of the permanent magnet synchronous motors. The difference is that the brushless DC motor does not use mechanical brush device, it uses hall sensor to replace carbon brush and commutator rotor in NdFeB permanent magnet materials. It has prominent performance over the traditional DC motor. The advantages of BLDCM are as follows: small volume, light-weight; the low torque is good, and the starting current is small. Stepless speed adjustment, wide range of speed regulation, strong overload ability; High efficiency, no excitation loss and carbon brush loss in the motor itself. Therefore, brushless DC motor is the most ideal speed regulating motor nowadays. Although brushless dc motor has many advantages, it still has some problems affecting its performance. One of them is the cogging torque. Cogging torque of electrical motors is the torque due to the interaction between the permanent magnets of the rotor and the statorslots of a Permanent Magnet (PM) machine. It is also known as detent or 'no-current' torque. This torque is position dependent and its periodicity per revolution depends on the number of magnetic poles and the number of teeth on the stator. Cogging torque might cause vibration and noise, being the reason why the motor cannot run smoothly, will affect its performance output. Therefore, the main idea of this paper is to reduce the cogging torque from the BLDCM. The research methods are as follows: Through analytical methods, using Fourier decomposition derived expression of cogging torque and energy method, it finds a way to prove that how these parameter like pole number and slot number of the cater, permanent magnet pole arc and stator slot width can affect on cogging torque of the BLDCM. Moreover, it deduced the motor parameters optimization design method too. Meanwhile, the way to reduce cogging torque by optimizing the permanent magnet, such as unequal thickness of permanent magnets and magnetic pole shift method is mentioned. Finally, several methods analysised in this paper are used in a 1200W brushless DC motor being applied to an electric vehicle. The computed cogging torque values and machine performance were compared with the experiment values of the machine. Based on the analysis of air gap the magnetic density and back EMF of the motor without load, and the study of the output torque and phase A current with the load, the optimal parameters to reduce cogging torque of the motor are found. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/20578 |
DOI: | 10.6342/NTU201702797 |
全文授權: | 未授權 |
顯示於系所單位: | 電機工程學系 |
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