臺灣博碩士論文加值系統

動圈揚聲器能量轉換效率低，只有5%的電能被轉換為聲能。揚聲器失效很多時候是由於音圈高溫。本文對揚聲器的電、機、聲特性和熱特性進行了闡述，分析了這些特性之間的相互影響。討論了渦流熱效應和強迫對流熱傳對音圈溫度的影響，並且採用有限元方法提出了耦合模型。

The efficiency of moving coil loudspeaker is very low. Roughly around 5% of electricity energy is transformed to acoustic energy and loudspeaker failure is mainly due to high temperature of voice coil. In this thesis, loudspeaker's electric, mechanical, acoustical and thermal behaviors have been studied, and the relationships between them have been discussed. The thesis focuses on the influence of Eddy current heating effect and convection cooling effect to the voice coil temperature. A conjugated FEM model is also raised.

1. Introduction 1
1.1. Motivation 1
1.2. Background and existing paper 1
1.3. Thesis organization 2
1.4. Structural details 3
1.5. Power compression 5
2. Electro-mechanical model 7
2.1. Gyrator 7
2.2. Voice coil part 9
2.3. Mechanical part 12
2.4. Mechanic-acoustic transducer 14
2.5. Acoustic part 15
2.6. Summary analysis 17
3. Thermal model 20
3.1. Heat source 20
3.2. Heat transfer mechanisms 22
3.3. Thermal lumped-element circuit model 23
3.4. Measurements of temperature and thermal parameters 28
3.5. Summary of linear thermal model 30
3.6. Nonlinear model 31
4. FEM Model 35
4.1. COMSOL Multiphysics 35
4.2. Model construction 35
4.3. Temperature dependent Electro-mechanical model 38
4.4. Initial and boundary conditions of thermal model 39
4.5. FEM Thermal model 40
4.6. FEM Electro-mechanical model 43
4.7. Conjugated model results 46
5. Conclusion and future work 47
References 48

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