本論文研究整合基於永磁同步發電機之浮動式離岸風場、基於雙饋式感應發電機之固定基座式離岸風場以及同步發電機組，透過線換相轉換器輔助二極體整流器、模組化多階轉換器以及高壓直流傳輸系統傳輸電力至電網，並針對其穩定度進行分析。為進一步提升系統之穩定性與性能，本論文使用模態控制理論對線換相轉換器輔助二極體整流器設計一組輔助阻尼控制器，即比例-積分-微分控制器，並引入鯨魚優化算法來更新此控制器之三個重要參數來進一步優化控制器的性能。最後本論文進行了穩態分析包含電力潮流、特徵值、根軌跡、頻域與時域模擬，包含動態分析及暫態分析。最後透過電網韌性分析，驗證了所提控制策略的有效性。

This thesis investigates the integration of a floating wind farm based on permanent magnet synchronous generators (PMSGs), a fixed-bottom wind farm based on doubly-fed induction generators (DFIGs), and synchronous generators. Power is transmitted to the power grid via a line-commutated converter assisted-diode rectifier (LCCA-DR), modular multilevel converters (MMCs), and a high-voltage direct current (HVDC) transmission system, with a comprehensive stability analysis conducted thereon. To further enhance system stability and performance, this thesis applies modal control theory to design an supplementary damping controller specifically, a proportional-integral-derivative (PID) controller for the LCCA-DR. Furthermore, the whale optimization algorithm (WOA) is introduced to update three critical parameters of this controller, thereby optimizing its performance. Finally, steady-state analyses, including power flow, eigenvalues, root locus, as well as frequency-domain and time-domain simulations incorporating dynamic and transient analyses, are carried out. The effectiveness of the proposed control strategy is ultimately validated through a grid resilience analysis.

[1] D. Moulas, M. Shafiee, and A. Mehmanparast, “Damage analysis of ship collisions with offshore wind turbine foundations,” Ocean Engineering, vol. 143, pp. 149-162, Oct. 2017.
[2] Global Wind Energy Council (GWEC), “Floating Offshore Wind - A Global Opportunity,” 2021.
[3] T. D. Pham, M. C. Dinh, H. M. Kim, and T. T. Nguyen, “Simplified floating wind turbine for real-time simulation of large-scale floating offshore wind farms,” Energies, vol. 14, no. 15, pp. 1-18, Jul. 2021.
[4] 李冠緯，整合浮動式離岸風場與再生能源場經模組化多階轉換器之多端高壓直流鏈饋入多機電力系統之穩定度分析，國立成功大學電機工程學系碩士論文，2025年7月。
[5] K. Wang, Z. Yuan, Q. Song, Q. Xin, B. Huang, W. Liu, and J. Feng, “Grid-forming offshore wind farm integration through LCC-assisted diode rectifier,” IEEE Trans. Power Delivery, vol. 40, no. 1, pp. 178-190, Feb. 2025.
[6] P. Meng, W. Xiang, Y. He, and J. Wen, “Communication-less reactive power control of grid-forming wind turbines connected to cascaded LCC-DR HVDC system,” IEEE Trans. Power Systems, vol. 39, no. 5, pp. 6740-6752, Sep. 2024.
[7] P. Meng, W. Xiang, Y. He, and J. Wen, “Coordination control of wind farm integrated cascaded hybrid HVDC system in weak grids,” IEEE Trans. Power Delivery, vol. 38, no. 3, pp. 1837-1847, Jun. 2023.
[8] P. Meng, W. Xiang, Y. Chi, Z. Wang, W. Lin, and J. Wen, “Resilient DC voltage control for islanded wind farms integration using cascaded hybrid HVDC system,” IEEE Trans. Power Systems, vol. 37, no. 2, pp. 1054-1065, Mar. 2022.
[9] Y. He, W. Xiang, B. Ni, X. Lu, and J. Wen, “Impact of strength and proximity of receiving AC systems on cascaded LCC-MMC hybrid HVDC system,” IEEE Trans. Power Delivery, vol. 37, no. 2, pp. 880-892, Apr. 2022.
[10] K. Wang, Q. Song, B. Zhao, Z. Yu, and R. Zeng, “Grid-forming control of offshore wind farms connected with diode-based HVDC links based on remote active power regulation,” IEEE Trans. Sustainable Energy, vol. 15, no. 2, pp. 1315-1327, Apr. 2024.
[11] R. Tu, W. Xiang, and J. Wen, “Optimal reactive power and voltage control in hybrid AC/DC collection and DR/MMC HVDC transmission system for offshore wind farms,” CSEE Journal of Power and Energy Systems, vol. 14, no. 15, pp. 1-11, Mar. 2026.
[12] H. Xiao, X. Huang, Y. Huang, and Y. Liu, “Self-synchronizing control and frequency response of offshore wind farms connected to diode rectifier based HVDC system,” IEEE Trans. Sustainable Energy, vol. 13, no. 3, pp. 1681-1692, Apr. 2022.
[13] Z. Yu, Q. Song, P. Zhang, B. Zhao, W. Liu, and K. Wang, “Startup strategy based on coordinated energy balance method of series-connected hybrid diode rectifier for integrating offshore wind farm,” in Proc. IECON 2024 - 50th Annual Conference of the IEEE Industrial Electronics Society, Chicago, IL, USA, Nov. 03-06, 2024, pp. 1-6.
[14] U. Raj and R. Shankar, “WOA based LFC of interconnected power system incorporating UPFC,” in Proc. 2019 2nd International Conference on Power Energy, Environment and Intelligent Control, Greater Noida, India, Oct. 18-19, 2019, pp. 254-258.
[15] D. Hu, Z. Zhao, Z. Lin, and N. Chen, “Aerodynamic characterization of a floating offshore wind turbine under pitch motion,” in Proc. 2025 4th International Conference on Green Energy and Power Systems, Hangzhou, China, Apr. 11-13, 2025, pp. 659-662.
[16] 曾宇賢，設計基於基因演算法之阻尼控制器於儲能系統以改善混合再生能源發電系統的穩定度，國立成功大學電機工程學系碩士論文，2025年7月。
[17] P. S. Kundur and O. P. Malik, Power System Stability and Control, 2nd ed. New York, NY, USA: McGraw-Hill, 2022.
[18] P. M. Anderson and A. A. Fouad, Power System Control and Stability, Ames, IA, USA: Iowa State University Press, 1997.
[19] P. C. Krause, O. Wasynczuk, and S. D. Sudhoff, Analysis of Electric Machinery and Drive Systems, NJ, USA: Wiley-IEEE Press, 2002.
[20] 林裕涵，同步發電機採用以模組化多階轉換器為基礎之高壓直流鏈連接至電網之穩定度分析，國立成功大學電機工程學系碩士論文，2023年7月。
[21] 李庭佑，以模組化多階轉換器為基礎之多饋入式高壓直流輸電系統連接再生能源之穩定度改善分析，國立成功大學電機工程學系碩士論文，2024年7月。
[22] D. Jitkongchuen, C. Sirikayon, and A. Thummano, “An adaptive whale optimization algorithm with Mahalanobis distance for optimization problems,” in Proc. 2022 Joint International Conference on Digital Arts, Media and Technology with ECTI Northern Section Conference on Electrical, Electronics, Computer, and Telecommunications Engineering, Chiang Rai, Thailand, Jan. 26-28, 2022, pp. 285-289.
[23] L. Wang, X. L. Peng, T. Y. Li, and Y. C. Hsu, “Grid resilience enhancement and stability improvement of an autonomous DC microgrid using a supercapacitor-based energy storage system,” IEEE Trans. Industry Applications, vol. 60, no. 2, pp. 1975-1985, Mar.-Apr. 2024.
[24] K. R. Padiyar, HVDC Power Transmission Systems, 2nd ed. Hoboken, NJ, USA: John Wiley & Sons, Inc, 2021.
[25] C. Zhang, D. Yang, and H. Mu, “Voltage-power relationship for DRU-HVDC connected OWF system,” in Proc. IEEE 24th Workshop on Control and Modeling for Power Electronics, Ann Arbor, MI, USA, Jun. 25-28, 2023, pp. 1-7.
[26] Y. Tang, Z. Zhang, and Z. Xu, “DRU based low frequency AC transmission scheme for offshore wind farm integration,” IEEE Trans. Sustainable Energy, vol. 12, no. 3, pp. 1512-1524, Jul. 2021.
[27] Y. Wang, W. Xiang, H. Zhang, and J. Wen, “Stability-oriented AC filter capacity design for hybrid DR-MMC HVDC system with grid-forming offshore WTGs,” in Proc. 2025 10th International Conference on Power and Renewable Energy, Hangzhou, China, Sep. 19-22, 2025, pp. 1044-1048.
[28] J. Wang, W. Du, Q. Fu, B. Ren, B. Ren, Q. Li, and H. Wang, “Transient stability analysis of MMC-HVDC connected DFIG-based wind farms in the electromechanical timescale,” IEEE Trans. Sustainable Energy, vol. 17, no. 1, pp. 116-128, Jan. 2026.
[29] T. Wang and X. Zhang, “Dynamic mode switching control architecture for grid-following/forming converters in high renewable penetration MMC-HVDC systems,” in Proc. 2025 International Conference on New Power System Technology, Hefei, China, Sep. 24-25, 2025, pp. 1-6.
[30] 武光山，採用以超級電容器為基礎之儲能設備於含有市電併聯型混合再生能源系統之性能改善，國立成功大學電機工程學系博士論文，2017年7月。
[31] Y. Huang, D. Wang, H. Yuan, and X. Yuan, “Modeling of grid-connected DFIG-based wind turbines for DC-link voltage stability analysis,” IEEE Trans. Sustainable Energy, vol. 6, no. 4, pp. 1325-1336, Oct. 2015.
[32] T. Gu, P. Wang, D. Liu, A. Sun, D. Yang, and G. Yan, “Modeling and small-signal stability analysis of doubly fed induction generator integrated system,” Global Energy Interconnection, vol. 6, no. 4, pp. 438-449, Aug. 2023.
[33] K. B. Thapa and K. Jayasawal, “Pitch control scheme for rapid active power control of a PMSG-based wind power plant,” IEEE Trans. Industry Applications, vol. 56, no. 6, pp. 6756-6766, Nov.-Dec. 2020.
[34] A. Safaeinejad, M. Rahimi, D. Zhou, and F. Blaabjerg, “Pitch control scheme considering entire dynamics and full-load region in PMSG-based wind turbines,” IEEE Trans. Sustainable Energy, vol. 16, no. 2, pp. 955-969, Apr. 2025.
[35] F. Guo, T. Zheng, and Z. Wang, “Comparative study of direct power control with vector control for rotor side converter of DFIG,” in Proc. 9th IET International Conference on Advances in Power System Control, Operation and Management (APSCOM 2012), Hong Kong, Nov. 18-21, 2012, pp. 1-6.
[36] I. Erlich, J. Kretschmann, J. Fortmann S. M.-Engelhardt, and H. Wrede, “Modeling of wind turbines based on doubly fed induction generators for power system stability studies,” IEEE Trans. Power Systems, vol. 22, no. 3, pp. 909-919, Aug. 2007.
[37] W. Wang, Y. Li, J. Hu, and J. Guo, “Current control and DC capacitor dynamic interaction in a cross-timescale manner in DFIG-WT dominated power systems,” IEEE Trans. Sustainable Energy, vol. 17, no. 1, pp. 143-157, Jan. 2026.
[38] Y. Zhu, Y. Li, L. Xu, B. Li, T. Li, and N. Liu, “Enhancing DC fault ride-through capability of grid-forming wind turbines connected via diode-rectifier based MMC-HVDC,” CSEE Journal of Power and Energy Systems, vol. 14, no. 15, pp. 1-15, May 2026.
[39] 阮名莎，採用高壓直流輸電系統以增強含有再生能源系統之電力系統穩定度，國立成功大學電機工程學系博士論文，2013年7月。
[40] 楊智皓，多端饋入式混合高壓直流傳輸系統連接離岸式風場之穩定度分析，國立成功大學電機工程學系碩士論文，2014年7月。
[41] J. Xu, X. Zhao, H. Jing, J. Liang, and C. Zhao, “DC fault current clearance at the source side of HVDC grid using hybrid MMC,” IEEE Trans. Power Delivery, vol. 35, no. 1, pp. 140-149, Feb. 2020.
[42] A. L. F. Acevedo, H. Nosair, and A. Venkatraman, “Design and valuation of high-capacity HVDC macrogrid transmission for the continental US,” IEEE Trans. Power Systems, vol. 36, no. 4, pp. 2750-2760, Jul. 2021.
[43] C. Lin, J. Zhou, R. Zeng, B. Li, and Q. Jiang, “Coordinated control strategy research of multi-terminal cascaded hybrid HVDC system,” in Proc. International Symposium on Power Electronics and Control Engineering (ISPECE), Montréal, Canada, May 18-22, 2025, pp. 1-9.
[44] J. Zhang, W. Yang, L. Chen, and Y. Mi, “Research on power balance control of hybrid cascaded DC transmission system,” 2026 8th Asia Energy and Electrical Engineering Symposium (AEEES), Chengdu, China, Mar. 27-30, 2026, pp. 457-462.
[45] C. Guo and W. Zhao, “Interaction analysis among multiple series-parallel connected LCC/MMC in hybrid cascaded HVDC system,” IEEE Trans Power Delivery, vol. 40, no. 2, pp. 974-987, Apr. 2025.