本論文提出三相三線LCL換流器模組系統之三部並聯架構，利用以正弦脈波寬度調變(SPWM)為基礎之解耦合分切合整直接數位控制來實現，並可依電網需求饋入實、虛功，以改善電網電流的品質。本研究之開關切換頻率為100kHz，為因應其較高的切換頻率及多樣的回授訊號，因此使用微控制器Renesas RX71M做為換流器控制核心，此微控制器擁有較短的類比/數位轉換時間與較多的轉換通道。
解耦合分切合整直接數位控制利用空間向量的觀念，將一個切換週期分切為數個區間，接著計算切換週期內開關狀態電壓平均值，進而推導出開關責任比率。此控制法不僅省略傳統abc至dq軸轉換處理，還可將電感值隨電流變化量納入考量，因此能夠有效簡化換流器的控制法，更降低了鐵芯的體積與成本。藉由此控制法搭配正弦脈波寬度調變，使得換流器三相電流可獨立控制，因此能有效抑制模組間的環流。此外，本研究採用主僕式同步控制架構，將三部換流器模組分類為主換流器與副換流器，並以同步的概念為基礎，由主換流器負責輸出並聯模組系統之初始同步訊號至其他副換流器，使得每部換流器模組輸出相同的功率，以達到均流之目的。最後本研究透過模擬與實作三部併網型三相三線LCL換流器並聯系統，驗證所提出的環流抑制與均流控制策略的可行性，並分析其損耗。
本研究的主要貢獻如下：第一、採用分切合整方法推導之解耦合直接數位控制法，可考慮電感值變化且降低控制方法的複雜程度。第二、提出基於正弦脈波寬度調變之開關責任比率計算方式，使每部換流器之三相電流皆可獨自追蹤其參考電流命令，來達到抑制環流的效果。第三、實作一套三部三相三線換流器並聯系統，且具有注入實、虛功至電網之功能。
關鍵字: 換流器並聯系統、解耦合直接數位控制、正弦脈波寬度調變、LCL濾波器、實虛功補償

This paper presents a three paralleled three-phase three-wire LCL inverters system with SPWM-based decoupled direct digital control with the division-summation (D-Σ) process. The system can inject active and reactive power into the grid by following the command of utility company to improve the quality of grid current. The switching frequency is 100 kHz in this research. For the high switching frequency and many kinds of feedback signals, micro-controller Renesas RX71M is chosen as the control center of the system because of the shorter A/D conversion time and more conversion channels.
Based on the concept of space vector, decoupled direct digital control with the D-Σ process divides one switching cycle into several time intervals, and then, calculates the average value of the switching-state voltage over one switching cycle and determines the duty ratio of switches. This control method not only omits the traditional abc-to-dq frame transformation processing, but also takes the filter inductance variation into consideration. Therefore, it can effectively simplify the control method and reduce the volume and cost of the core. The control method with SPWM can make each inverter track its phase sinusoidal current reference independently, thus eliminating circulating currents effectively. In addition, this research adopts a master-slave synchronization control architecture to classify the inverters as master-inverter and slave-inverter. The master-inverter sends a synchronization signal at the beginning to slave-inverters, so that all inverters output the same power to achieve equal current distribution. Finally, simulated and experimental results are used to verify the control method for a paralleled three-phase three-wire LCL inverters.
The major contributions of this research are as follows: First, adopting the D-Σ digital control can take the filter inductance variation into consideration and reduce the complexity of control method. Secondly, presenting a duty ratio calculation method based on SPWM, making each inverter track the current reference of each phase individually. Thirdly, implementing a three paralleled three-phase three-wire LCL inverter system, and proving the capability of injecting active and reactive power into the grid.

Keywords—paralleled inverter, D-Σ digital control, SPWM, LCL filter and active/reactive power compensation

目錄
摘要 i
Abstract ii
誌謝 iv
目錄 v
圖目錄 viii
表目錄 xii
第一章 緒論 1
1-1研究背景動機 1
1-2文獻回顧 2
1-2-1均流控制策略 2
1-2-2環流控制策略 4
1-3論文大綱 11
第二章 系統架構與控制策略 12
2-1單模組換流器系統架構 12
2-2解耦合分切合整直接數位控制 13
2-3多模組換流器並聯系統架構 20
第三章 換流器周邊電路 25
3-1輔助電源 25
3-2開關驅動電路 27
3-2-1緩衝器SN74LVC244 27
3-2-2開關驅動電源 28
3-2-3開關驅動電路 29
3-3電壓/電流回授電路 30
3-3-1直流鏈電壓回授 30
3-3-2電網電壓、濾波電容電壓回授電路 31
3-3-3電感電流回授電路 33
3-3-4直流鏈電流回授 35
3-4保護電路 36
3-4-1過壓/過流保護電路 37
3-4-2電壓箝位保護電路 38
3-4-3輔助電源偵測電路 38
3-4-4電網斷開電路 39
3-4-5緊急開關電路 40
第四章 系統韌體架構與控制流程 41
4-1系統韌體架構 41
4-2微控制器RX71M簡介 42
4-3換流器控制流程 48
4-3-1主換流器主程式 48
4-3-2主換流器類比/數位中斷副程式 50
4-3-3副換流器主程式 51
4-3-4副換流器類比/數位中斷副程式 53
第五章 系統模擬與實測驗證 54
5-1電氣規格 54
5-2實務考量 55
5-2-1 電感值變化 55
5-2-2 雙層隔離線 57
5-2-3 類比/數位轉換誤差 58
5-3 Matlab/Simulink模擬 60
5-4 模擬與實測波形比較 63
5-5 損耗分析 74
5-5-1電感損耗 74
5-5-2功率開關損耗 77
第六章 結論與未來研究方向 81
6-1 結論 81
6-2 未來研究方向 82
參考文獻 83

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