研究報告指出為了降低由非線性負載所造成的諧波失真電流而廣泛使用被動濾波器，未經濾波處理的諧波電流流至電力系統將進一步造成電壓失真而影響敏感用戶。由於被動濾波器的諸多缺點，因此這篇論文的背景將著重在並聯式主動濾波器。
評估並聯式主動電力濾波器的電流控制器的效能與特性是這篇論文著重的關鍵。考慮主動式電力濾波器最重要的兩個部分分別為諧波偵測法則與內部電流控制器。諧波偵測法則是基於P-Q 理論下來完成，而電流控制器的技術研究則包括：遲滯型電流控制、適應性/可調式遲滯電流控制、預測型電流控制以及比例積分控制。上述電流調節器的研讀皆在同操作條件下加以分析其相對優、缺點。
模擬結果包括的用於兩種負載條件下9.3kW二極體整流器負載，而在應用並聯式主動電力濾波器之後可以明顯觀察到系統電流濾波回弦波波形。為驗證其有效性與結果而使用了MATLAB/SIMULINK 軟體來加以模擬四種不同的電流調節器。
在分析四種不同電流調節器的模擬結果之後，可以注意到遲滯電流控制提估了較好的效果。電流控制器的效果優劣依序是遲滯電流控制、預測型電流控制。其中，比例積分控制以及適應性/可調式遲滯電流控制則由於穩定性考量與使用電壓限制而從上述排序中允以忽略

Extensive use of passive filters has been reported in order to reduce current harmonic distortion levels produced by nonlinear loads. Due to numerous drawbacks associated with passive filters, several active filter topologies have been applied, however the background of this thesis will focus on “Shunt Active Power Filters”.
The assessment of the performance of the current controllers of the Shunt Active Power Filter (SAPF) is the key point for this thesis. The two most important parts to be concern with respect to the Active Power Filter (APF) is the harmonic detection method and the inner current controller. The harmonic detection method is based on the “P-Q Theory” while the current control techniques studied are: Hysteresis Current Control, Adaptive/Variable Hysteresis Current Control, Predictive Current Control and PI Current Control. Advantages and disadvantages for each current regulator will be highlighted based on same operating conditions.
Simulation results are obtained for a 9.3 KW diode rectifier load under two load conditions, where after the application of the SAPF it is clear how the source current becomes sinusoidal. MATLAB/SIMULINK software is used, to validate the results.
After analysis of simulation results, Hysteresis Current Control and Predictive Current Control provides better performance, while Adaptive/Variable Hysteresis Current Control and PI Current Control should be left for other system conditions.

Declaration iii
Acknowledgments iv
摘要 v
Abstract vi
Table of Contents vii
Table of Figures xi
Table of Tables xviii
Abbreviations xx
Chapter 1 Introduction 1
1.2 Thesis Structure 2
Chapter 2 Literature Review 3
2.1 Introduction 3
2.2 Nonlinear Loads 4
2.3 Types of Nonlinear Loads 5
2.4 Standard of Harmonic Distortion 6
2.5 Methods Available to Reduce THD 8
2.6 Passive Filters 10
2.6.1 Types of Passive Filters 10
2.6.2 Classification of Passive Power Filters 12
2.6.3 Advantages of Passive Filters [9] 15
2.6.4 Disadvantages of Passive Filters [9] 15
2.7 Active Filters 16
2.7.1 Classification of Active Filters 17
2.7.2 Shunt and Series Active Filters 20
2.7.3 Hybrid Active Filters 22
2.8 Types of PWM Converters for Active Filters 24
2.9 Introduction to PQ Theory 27
2.9.1 Clarke Transformation 28
2.9.2 Three Phase Instantaneous Active Power 29
2.9.3 PQ Theory 30
2.10 PQ Theory in Three Phase, Three Wire Systems 30
2.11 Instantaneous Power Components 31
2.12 Pulse Width Modulation (PWM) 34
Chapter 3 Principle of Operation 37
3.1 Introduction 37
3.2 General Description of Shunt Active Filters 38
3.3 Active Filter Controller 40
3.4 Three Phase, Three Wire Shunt Active Filters 40
3.5 PQ Algorithm for the Shunt Active Filter 42
3.6 Current Control Techniques for Shunt Active Filter 44
3.6.1 Hysteresis Current Control 45
3.6.2 Adaptive/Variable Hysteresis Current Control 48
3.6.3 Predictive Current Controller 52
3.6.4 PI Current Control 54
3.7 Stability Analysis of the Predictive Current Controller 55
3.8 Design Considerations of Shunt Active Filter 59
3.8.1 Inverter DC Voltage 59
3.8.2 Coupling Inductor 60
3.8.3 RC Low Pass Filter 61
3.8.4 DC Capacitor Design 61
3.9 DC Voltage Soft Startup 62
3.10 Control Algorithm Under Unbalance Conditions 64
3.10.1 Positive Voltage Sequence Detector 65
Chapter 4 Simulation Results 67
4.1 Introduction 67
4.2 Simulation of Current Controllers 74
4.2.1 Hysteresis Current Control of Shunt Active Power Filter 74
4.2.2 Adaptive/Variable Hysteresis Current Control 81
4.2.3 Predictive Current Control of Shunt Active Power Filter 88
4.2.4 PI Current Control of Shunt Active Power Filter 94
4.3 Transient Analysis of Current Controllers 101
4.3.1 Transient Analysis of Hysteresis Current Controller 101
4.3.2 Transient Analysis of Variable/Adaptive Hysteresis Current Control 104
4.3.3 Transient Analysis of Predictive Current Control 107
4.3.4 Transient Analysis of PI Current Control 109
4.4 Comparative Evaluation of Current Controllers 112
4.5 PI DC Voltage Regulator for DC Capacitor Using Soft Startup 114
4.6 Case Study for Unbalanced Source Voltages and Balanced Nonlinear Load 117
4.6.1 Hysteresis Current Control Under Unbalanced Source Conditions 119
4.6.2 Predictive Current Control Under Unbalanced Source Conditions 122
4.6.3 Summary of Results for Unbalanced Conditions 124
Chapter 5 Conclusions and Future Work 126
References 127
Appendix A 131

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