應用正負序估測器設計靜態同步補償器於電網不平衡之控制

Applications of Positive and Negative Sequence Observers for STATCOM Control Under Unbalanced Grid Faults

盧明佛(Lu, Ming Fo)

指導教授 ： 朱家齊

國立清華大學/電機資訊學院/電機工程學系/碩士(2015年)

摘要

此篇論文探討STATCOM於不平衡電網故障下的控制法。首先，為了估測出電網故障時的正負序電壓電流，此篇引用了狀態空間下正負序電壓電流觀測器。在控制器設計方面，則是使用傳統串級內外迴圈電流控制架構，內迴圈為響應速度較快的電流控制，外迴圈則是響應速度較慢的電壓控制，這些控制器的參數需要精確地設計，以符合內外迴圈控制器適當的頻寬關係，另外控制器的頻寬也需額外考量觀測器響應速度，使得整體控制系統穩定，STATCOM正常運作。除了傳統正序電壓電流控制法之外，本篇也利用負序電流注入且加以控制，當市電故障的情形下，STATCOM能避免電流過流造成儀器損壞，並繼續運作以達到給定的故障暫態響應。完成STATCOM補償器設計後，利用模擬分析工具SIMULINK做初步的驗證，隨後使用Matlab Embedded Coder自動生成代碼，快速生成硬體實驗用之語言程式代碼來執行測試，從控制演算法提出、模型模擬建立、模擬測試、嵌入式程式生成，都在同一工作環境下執行，可解決不同開發軟體間銜接的問題，使研究過程更有效率並有系統的執行。此外，為了模擬故障時電壓驟降情形，此篇也提出了驟降電壓的實際電路，使用較容易設計的並聯式阻抗分壓，讓共用耦合點(Point of Common Coupling, PCC)電壓驟降，達到與故障一樣情況。最後，模擬以及硬體實驗結果將達到預期的動態規格。

關鍵字

電壓無感測器 ； 不平衡故障 ； 正負序分離法 ； STATCOM ； Embedded Coder ； 驟降電路

並列摘要

This thesis studies STATCOM control when an unexpected unbalanced fault is experienced in the grid. In order to extract the corresponding positive sequences and negative sequences of voltage/current phasors, both voltage/current sequence observers will be considered first. Then the controller design is based on the conventional cascaded inner/outer loop current control configuration. These control parameters must be designed precisely to meet proper bandwidth relationship among observer, inner-loop current control, and outer-loop voltage control, so that it can conform the given transient performance. In order to verify the correctness of the proposed control, dynamical simulations in SIMULINK will be investigated. Then, Matlab Embedded Coder will utilized for generating DSP codes for hardware implementations. A three-phase balanced voltage dip circuit is implemented for hardware experiments of unbalanced faults. Both simulations and experimental work are conducted. Both results provide satisfactory dynamical performances of the proposed controller.

並列關鍵字

Sensorless Control ； Unbalanced Fault ； Sequence Separations ； STATCOM ； Embedded Coder ； Voltage Dips

參考文獻

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