本論文針對三階中性點箝位轉換器，提出一套脈衝寬度調變技術，能抑制三相負載中性點的高頻共模電壓，將其峰值減至一半；同時利用零序注入技術，當上下臂電容電位不平衡時，藉由迴授轉換器輸出電流資訊，判斷流入上下臂電容中點的電流，決定適當的瞬時零序注入電壓值，以達到電容中性點電壓平衡控制的效果。最後將此脈衝寬度調變技術應用於三相不斷電系統(UPS)，並以電腦模擬與實驗驗證其效能。

The thesis presents a pulse width modulation (PWM) technology for three-level neutral-point-clamped (NPC) converters, which can reduce half magnitude of common-mode voltage (CMV). Also, by feedback of the converter output current polarity, and utilizing zero-sequence-injection (ZSI) technique, the strategy can also possess neutral-point potential control ability. The proposed method is validated as uninterruptable power supplies (UPS) by simulation and experimental results.

摘要 I
Abstract II
致謝 III
Table of Contents IV
List of Figures VI
List of Tables XIV
CHAPTER 1 Introduction 1
1.1 Motivation 1
1.2 Contributions of the Thesis 3
1.3 Outline of the Contents 4
CHAPTER 2 Literature Review 5
2.1 Introduction 5
2.2 Active Zero State PWM for Two-Level Converters 18
2.3 Phase Disposition PWM for Three-Level NPC Converters 21
2.4 Neutral-Point Potential Control for NPC Converters in PDPWM 31
CHAPTER 3 Operation Principal 43
3.1 Introduction 43
3.2 Control Block Diagram 44
3.3 Zero Redundant State PWM for NPC Converters 51
3.4 Neutral-Point Potential Control for NPC Converters in ZRSPWM 61
CHAPTER 4 Simulation 72
4.1 Introduction 72
4.2 Common-Mode Voltage Reduction 85
4.3 Neutral-Point Potential Control in ZRSPWM 95
CHAPTER 5 Implementation and Experimental Results 97
5.1 Introduction 97
5.2 Hardware Implementation 99
5.3 Design of the Switching Ripple Filter 100
5.4 Dead-Time 104
5.5 Experimental Results 110
CHAPTER 6 Conclusions and Future Work 118
6.1 Conclusions 118
6.2 Future Work 118
Appendix: Operational Process of Test Bench 120
References 123

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