本文以數位控制器實現可操作於三相電網輸入不平衡環境及輸出電容電壓自動平衡功能之三相四線四臂型Vienna整流器。現今低壓配電系統以三相四線制為主流，然而傳統PWM整流器多採用三臂之拓樸，若直接將中性線與輸出直流電容中性點作連接，便難以控制由負載不平衡時所產生的零序電流。為有效控制零序電流，本文採用四臂型Vienna整流器，除了擁有傳統Vienna整流器導通損耗低、可雙向操作、功率因數高、輸入諧波量低且系統可靠性高等優勢外，額外加入的一臂更可提升對於零序電流之控制力。然而與傳統三臂型Vienna整流器相同，由於輸出為兩組電容串聯組成，實際操作可能發生電容不均壓之問題，本文將介紹如何通過控制法解決輸出電容電壓不均之問題。在實際應用中，除了電容不均壓的問題外，還有可能遇上輸入三相電壓不平衡之情況，本文亦將討論此問題並提出解法。在調變技術上，本文選用了CBPWM中的均值零序注入調變，除了擁有與SVPWM相同，直流電壓利用率較高的優點外，還有易於實現數位化的優點。本文通過電路模擬軟體PSIM建構出一組額定功率8kW，輸出直流電壓800V，輸入交流電壓220V之Vienna整流器並進行模擬測試。實作電路除了進行適當的元件選用外，亦通過損耗分析以預測實際電路的轉換效率。數位控制核心選用德州儀器公司出產之TMS320F28379D，實現系統控制並且驗證硬體設計與控制法。

This thesis uses a digital controller to implement a three-phase four-wire four-legs type Vienna rectifier with the functions of operating in unbalanced grid voltage and auto balancing output capacitor voltage. The three-phase four-wire is the main topology of the low-voltage distribution network. However, the traditional PWM rectifier usually use three-legs topology, if it makes a connection between the neutral wire and neutral point of output capacitor, it is hard to control the zero-sequence current produced by unbalanced load. In order to control the zero-sequence current effectively, this thesis use four-legs type Vienna rectifier, which has the advantages of low conduction loss, bidirectional operation, high power factor, low input harmonics, and high system reliability. The additional legs can improve the control of zero-sequence current. The issue of output capacitor voltage unbalanced is the same with traditional three-legs type Vienna rectifier because the output terminal is composed of two capacitors connected in series. Besides, the input three-phase voltage might be unbalanced in reality, in this thesis would also introduce the solution of such matters. The average zero-sequence component injection of Carrier-based PWM is adopted as the modulation method, which has the high utilization of DC voltage as SVPWM, it also has the advantage of easy digitization. This thesis uses the circuit simulation software PSIM to construct a Vienna rectifier with rated power of 8kW, output DC voltage 800 V and AC voltage 220 V to verify the function. In addition to select proper components, also analysis the losses to predict the efficiency of implementation circuit. The digital controller is the TMS320F28379D from Texas Instruments to realize system control and verification.

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