近年雲端硬體設備日益增加。伺服中心安裝大量的伺服算運機組，這些伺服運算機組具備了功率因數校正功能，能使輸入電流為理想的正弦波。然而，電磁干擾排放的規範，每一個伺服運算機組需安裝交流濾波電容以符合法規。除此之外，為預防停電的問題，這些伺服設備通常會搭配不斷電系統（ＵＰＳ），其交流側電容也是非常大。大量的交流濾波電容與市電電感導致低的諧振頻率，面對於供電較差的環境或是諧波負載源，會導致用戶端電壓與市電電流的嚴重失真。
　　本篇論文將並聯型主動濾波器開發使用在伺服雲端設備的不斷電系統的潛能，發展出諧波隔阻的特性。所提出的諧波隔阻特性是模擬一個諧波電阻串聯於市電側電感，將並聯的電容作隔離。方法有五種：主動阻尼、諧波隔阻、加強型顯著諧波的諧波隔阻、同步框比例積分諧波控制搭配諧波隔阻和靜止框比例諧振控制搭配諧波隔阻。前面三個是前饋控制，後面兩個是回饋控制。這五種的控制方法能夠抑制用戶端與市電側的並聯與串聯諧振，改善電力品質。實驗室測試結果針對電壓電流的波形進行頻譜分析，評估這五種的濾波性能，是否能達到電力公司所要求的電力品質。

Cloud computing has gained significant momentum in recent years. Server farms, the back bone of the cloud computing, also grow in the same pace. These server farms are equipped with thousands of computer server racks. Although these computer servers are powered by PFC-front end, which draws almost perfect sinusoidal current, large amount of AC side filter capacitors are installed to meet the EMI emission requirement. The resulting resonance frequency between the line/system inductance and the filter capacitors becomes low, thus typical back ground harmonic distortion of the grid or neighboring harmonic-producing loads can cause significant voltage and current distortion. In this thesis, a harmonic isolation technique based on a shunt active power filter is explored. The proposed technique can suppress the shunt and the series resonance, and maintain the power quality of the facility. Laboratory test results are provided to validate the performance of the proposed technique.

中文摘要 I
Abstract II
致謝 III
Contents IV
List of Figures VII
List of Tables XV
Chapter 1 1
1. Introduction 1
1.1 Introduction 1
1.2 Thesis Organization 2
Chapter 2 3
2. Literature Survey 3
2.1 Introduction 3
2.2 Harmonic Resonance Phenomenon 3
2.3 Load Compensation Type of Active Power Filter 7
2.4 Voltage Detection Type of Active Power Filter 10
2.5 Grid Current Compensation of Active Filter 15
2.6 Summary 21
Chapter 3 22
3. Principles of Operation 22
3.1 Introduction 22
3.1.1 Controller description 22
3.1.2 Design of the harmonic isolation 23
3.2 Harmonic Isolation 25
3.3 DC-Bus Voltage Control 26
3.4 Harmonic Isolation with Dominant Harmonics Enhancement 27
3.5 Synchronous Reference Frame PI Control for Selected Harmonics 30
3.6 Stationary Reference Frame PR Control for Selected Harmonics 32
3.7 Summary 34
Chapter 4 35
4. Experimental Results 35
4.1 Introduction 35
4.2 Experimental Test Bench 35
4.3 Laboratory Test Results 37
4.3.1 Active Damping 37
4.3.1.1 Operating at No Load 38
4.3.1.1.1 Resonance Frequency = 368 Hz 38
4.3.1.1.2 Resonance Frequency = 720 Hz 39
4.3.1.1.3 Resonance Frequency = 1061 Hz 41
4.3.1.2 Operating at Rated Load 43
4.3.1.2.1 Resonance Frequency = 368 Hz 43
4.3.1.2.2 Resonance Frequency = 720 Hz 45
4.3.1.2.3 Resonance Frequency = 1061 Hz 47
4.3.1.3 Analysis of Experimental Results 50
4.3.2 Harmonic Isolation 51
4.3.2.1 Operating at No Load 52
4.3.2.1.1 Resonance Frequency = 368 Hz 52
4.3.2.1.2 Resonance Frequency = 720 Hz 53
4.3.2.1.3 Resonance Frequency = 1061 Hz 55
4.3.2.2 Operating at Rated Load 57
4.3.2.2.1 Resonance Frequency = 368 Hz 57
4.3.2.2.2 Resonance Frequency = 720 Hz 59
4.3.2.2.3 Resonance Frequency = 1061 Hz 61
4.3.2.3 Analysis of Experimental Results 64
4.3.3 Harmonic Isolation with Dominant Harmonics Enhancement 65
4.3.3.1 Operating at No Load 66
4.3.3.1.1 Resonance Frequency = 368 Hz 66
4.3.3.1.2 Resonance Frequency = 720 Hz 67
4.3.3.1.3 Resonance Frequency = 1061 Hz 69
4.3.3.2 Operating at Rated Load 71
4.3.3.2.1 Resonance Frequency = 368 Hz 71
4.3.3.2.2 Resonance Frequency = 720 Hz 73
4.3.3.2.3 Resonance frequency = 1061 Hz 75
4.3.3.3 Analysis of Experimental Results 78
4.3.4 Synchronous Reference Frame PI Control for Selected Harmonics 79
4.3.4.1 Operating at No Load 80
4.3.4.1.1 Resonance Frequency = 368 Hz 80
4.3.4.1.2 Resonance Frequency = 720 Hz 81
4.3.4.1.3 Resonance Frequency = 1061 Hz 83
4.3.4.2 Operating at Rated Load 85
4.3.4.2.1 Resonance Frequency = 368 Hz 85
4.3.4.2.2 Resonance Frequency = 720 Hz 87
4.3.4.2.3 Resonance Frequency = 1061 Hz 89
4.3.4.3 Analysis of Experiment Results 92
4.3.5 Stationary Reference Frame PR Control for Selected Harmonics 93
4.3.5.1 Operating at No Load 94
4.3.5.1.1 Resonance Frequency = 368 Hz 94
4.3.5.1.2 Resonance Frequency = 720 Hz 96
4.3.5.1.3 Resonance Frequency = 1061 Hz 97
4.3.5.2 Operating at Rated Load 99
4.3.5.2.1 Resonance Frequency = 368 Hz 99
4.3.5.2.2 Resonance Frequency = 720 Hz 103
4.3.5.2.3 Resonance Frequency = 1061 Hz 106
4.3.5.3 Analysis of Experiment Results 109
4.3.6 Summary 110
Chapter 5 111
5. Conclusion and Future Work 111
5.1 Conclusion 111
5.2 Future Work 111
REFERENCES 112

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