【講座題目】模塊化多電平變換器的建模與控制
【時 間】2023年11月22日 下午：14:00-15:20
【地 點】北京校區 主樓D260會議室
【主講人】李澤元，美國國家工程院院士、中國工程院外籍院士
【主講人簡介】
李澤元教授(Fred C. Lee)于1968年在臺灣國立成功大學獲得電氣工程學士學位，隨后于1972年和1974年分別在杜克大學獲得電氣工程碩士和博士學位。李澤元教授是弗吉尼亞理工大學的名譽特聘教授，也是弗吉尼亞理工大學電力電子研究中心(CPES)的創始人和名譽主任。作為CPES的學術帶頭人，李教授主持了一系列項目，涵蓋了研究、技術開發、教育推廣、產業合作和技術轉移。CPES致力于滿足行業需求，推動其研究和成果應用于產業。迄今為止，全球超過250家公司受益于該研究中心的產業合作項目。由于其在產業合作、技術轉移、教育和推廣等方面的貢獻，CPES被美國國家科學基金會(NSF)評為模范工程研究中心(ERC)。李教授的研究方向為高頻功率變換、磁性和電磁干擾、分布式電力系統、可再生能源、電能質量、以及高密度電子封裝、集成、建模和控制。李教授擁有107項美國專利，并發表了超過340篇期刊論文和790多篇經過評審的技術論文。在弗吉尼亞理工大學任職期間，李教授指導了90名博士和94名碩士學生完成學業。李教授是美國國家工程院院士、中國工程院外籍院士。根據Research.com網站上的D-Index排名，李教授是電子與電氣工程學科的世界頂尖學者之一。
Fred C. Lee received his B.S. degree in electrical engineering from the National Cheng Kung University in Taiwan in 1968, and his M.S. and Ph.D. degrees in electrical engineering from Duke University in 1972 and 1974, respectively.Dr. Lee is a University Distinguished Professor Emeritus and Founder and Director Emeritus of CPES, a preeminent academic center in power electronics research at Virginia Tech. As CPES Director, Dr. Lee led a program that encompasses research, technology development, educational outreach, industry collaboration, and technology transfer. CPES focuses its research on meeting industry needs and allows industry to benefit from the Center's research and outputs. To date, more than 250 companies worldwide have benefited from the industry partnership program. The center has been cited by NSF as a model ERC for its industry collaboration and technology transfer, education, and outreach programs.Dr. Lee's research interests include high-frequency power conversion, magnetics and EMI, distributed power systems, renewable energy, power quality, high-density electronics packaging and integration, and modeling and control.Dr. Lee holds 107 U.S. patents and has published over 340 journal articles and over 790 refereed technical papers. During his tenure at Virginia Tech, Dr. Lee has supervised to completion 90 Ph.D. and 94 Master's students.Dr. Lee is a member of the U.S. National Academy of Engineering, and a foreign member of the Chinese Academy of Engineering in the People’s Republic of China. According to Research.com D-Index ranking, Dr. Lee is among the world’s top scholars within the discipline of Electronics and Electrical Engineering.
【報告內容簡介】
模塊化多電平變換器（MMC）被認為是可再生能源與現有公用事業電網之間的關鍵接口技術，然而當前MMC控制復雜且不直觀。由于MMC系統狀態量遠大于控制量，為最小化其內部環流而拓展的控制模糊不清。若沒有對MMC進行合適的建模和控制，MMC在運行時會產生大量環流，導致大體積儲能電容器被過度使用。采用狀態平面分析技術，以圖形方式給出了MMC兩種類型的環流，一種與MMC輸入和輸出能量交換有關，另一種與MMC內上下橋臂能量交換有關。此外，兩個功率流本質上是正交的，這意味著各個功率路徑上的控制獨立。因此，采用坐標轉換，建立了解耦的等效電路模型，獨立控制管理各個功率流，明確了消除環流的方法。
Modular multilevel converter is deemed the key interface technology between renewable energy sources and the existing utility power grids. However, the interface control currently deployed is rather complicated and counterintuitive. Since the systems states are far greater than the means of control, the extend of control to minimize the circulating energy was rather ambiguous. Without proper modeling and control, this system is often operated with large circulating energy, resulting in excessive use of the bulky energy storage capacitors.
Employing state-plane analysis techniques, two types of circulating energies are delineated graphically, one related to the energy exchange between input and output, and the other related to the energy swapping between upper arm and lower arm. Furthermore, these two power flows are orthogonal in nature, implying that the means of control for each power flow path are independent. Consequently, a coordinate transformation is employed, leading to a decoupled equivalent circuit model. Each power flow path is governed by it’s own control law. Methods of eliminating circulating energy are clearly identified.