本文使用了雙向互連轉換器作為直流端與交流端功率傳輸的主要系統。與現有的純交流微電網不同，本文研究的範圍包含幾種不同的技術，並對其做一個技術的整合。在雙向互連轉換器啟用的狀況下，交流端的下垂控制和直流端的下垂控制使得功率在兩個系統間傳輸，並且透過雙向互連轉換器達到功率共享的效果。這個部分主要的挑戰在要管理兩種不同型態的功率，勢必需要依賴交流端、直流端以及雙向互連轉換器的互相配合。慣量模擬的技術也有在本研究中進行討論，分別應用在交流端、直流端以及雙向互連轉換器端，主要目的是改善在負載變動時電壓或頻率的偏差，使系統運作在穩定的狀態下。本研究也對穩定度做了分析，其中包含分析了不同參數對系統穩定度的影響，並從分析的結果選擇合適的參數。本文開發出合適的控制方案，並考慮了多種情境來控制整個系統。最後使用模擬軟體進行理論的驗證，並且再透過硬體的建置進行實驗，做進一步的驗證，以確保本研究使用的控制方法的可行性。

We will study operations and control of bidirectional interlinking converter (BIC)s in this paper. The BIC will be used as an energy buffer between DC and AC microgrids (MGs). When the BIC is enabled, the droop control at the DC side and that at the AC side will enable the power transfer between two sub-systems. Thus the proper power sharing can be achieved with the aid of the BIC. Since two different types of MGs are involved, cooperative control among AC MGs, DC MGs and BIC are considered. In addition to the droop control, the inertia emulation (IE) technology is also investigated in this study. The main purpose of IE is to improve the deviation of frequency or voltage when the system load changes. Thus, the entire power grid will be more stable. To ensure the stability of the closed-loop system, effects of various parameters of the system is investigated. To validate the effectiveness of the proposed BIC control scheme, both simulation studies and hardware experiments are performed. Both results can demonstrate that the proposed BIC control can achieve these desired control objectives.

Abstract ...........................................................I
摘要 ...............................................................II
致謝 ..............................................................III
Contents ..........................................................IV
List of Figures ...................................................VI
List of Tables ..................................................VIII
Nomenclature ......................................................IX
1 Introduction .....................................................1
1.1 Motivation .....................................................1
1.2 Literature Survey ..............................................2
1.3 Contribution ...................................................4
2 Hybrid AC/DC Microgrids ..........................................6
2.1 AC Side ........................................................6
2.1.1 Voltage Control ..............................................7
2.1.2 Power Control ................................................8
2.1.3 Current Control ..............................................8
2.1.4 Droop Control ................................................9
2.2 DC Side .......................................................11
2.2.1 I-V Droop ...................................................12
2.2.2 V-I Droop ...................................................13
2.3 BIC ...........................................................14
2.3.1 Grid-Supporting .............................................14
2.3.2 Dual Droop ..................................................15
2.4 E-Droop .......................................................16
2.4.1 PI Droop ....................................................17
2.4.2 Grid-Forming ................................................18
2.4.3 Mixed droop .................................................18
2.5 Summary .......................................................19
3 Control of BICs .................................................20
3.1 Droop Control .................................................20
3.2 Inertia Emulation .............................................22
3.2.1 Inertia Emulation of BIC ....................................23
3.2.2 Inertia Emulation of AC Side ................................25
3.3 Summary .......................................................27
4 Simulation Studies and Hardware Experiments .....................28
4.1 Simulation Platform ...........................................28
4.2 Hardware Platform .............................................30
4.3 Experiment Procedure ..........................................31
4.4 Simulation Results ............................................32
4.4.1 I-V Droop V-I Droop control methods comparison ..............32
4.4.2 Comparison of inertia emulation control methods .............35
4.5 Case 1 ........................................................36
4.5.1 Matlab simulation results of Case 1 .........................36
4.5.2 PLECS simulation results of Case 1 ..........................39
4.5.3 Hardware Experiments ........................................42
4.6 Case 2 ........................................................46
4.7 Summary .......................................................47
5 Conclusion and Future Work ......................................48
5.1 Conclusion ....................................................48
5.2 Future Work ...................................................49
5.2.1 Secondary control technology ................................49
5.2.2 Reactive power sharing technology ...........................49
Reference .........................................................50

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