本論文旨在探討一三相三線換流器，並以二極體式中性點電位箝位(Neutral Point Clamping, NPC)的三階層架構來研製，利用空間向量脈波寬度條變法(Space Vector Pulse Width Modulation, SVPWM)產生換流器的電壓調變訊號，基於SVPWM下加入電容中性點電位的平衡控制來解決輸入端電容電壓不平衡的問題，負載和換流器輸出之間搭配LCL濾波器來過濾開關產生的高次諧波量同時能減輕輸出端的諧波成分；在數位控制的環境下來實現雙迴路控制使電路能夠穩定地在三相平衡負載下操作。三階層換流器的特點在於電壓的諧波量比傳統兩階層的換流器還少，在同樣的輸入電壓條件下，三階層架構所承受的元件應力較二階層來的低，換言之，三階層能應付更高的輸入電壓條件。在篩選調變技術時，本文首選SVPWM，因為此條變法存在電壓利用率較高、對開關狀態的切換時間來得更容易控制、生成較低失真的電流波形的特點，所以本論文挑選此調變技術作為調變主軸。本論文在PSIM的電路模擬軟體環境下，實現一套800 V直流輸入電壓對220 V交流輸出電壓的8 kW額定功率三相換流器，並採用內部的C-block執行模擬驗證執行數位控制的真實控制情況。本論文採用由德州儀器公司所製造的 TMS320F28379D開發版來作為核心控制並實現及驗證系統的控制迴路。

This paper aims to investigate a three-phase three-wire inverter using the three-level topology with Diode Neutral Point Clamped. The Space Vector Pulse Width Modulation is employed to generate voltage modulation signals for the inverter. To solve the issue of unbalanced input capacitor voltage, a balancing control of the neutral point potential of the capacitors is based on SVPWM. An LCL filter is used between the load and the inverter output to filter high-order harmonics generated by the switches and mitigate output harmonic components. The system is implemented under digital control to achieve dual-loop control, enabling stably operate under three-phase balanced loads. The three-level inverter exhibits lower voltage harmonics compared to conventional two-level inverters, and it can withstand higher input voltage conditions due to reduced component stress. SVPWM is selected as the preferred modulation technique for its features in higher voltage utilization, easier control of switch state switching times, and generation of lower distortion current waveforms. In this thesis, an 8 kW rated power three-phase inverter is implemented with an 800 V DC input voltage and a 220 V AC output voltage in the PSIM circuit simulation software environment. The simulation verification is conducted with internal C-block for digital control, representing real control scenarios. The TMS320F28379D development board manufactured by Texas Instruments is used as the core controller to implement and validate the system's control loops.

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