期刊
2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)
卷 -, 期 -, 页码 3402-3406出版社
IEEE
DOI: 10.1109/ECCE47101.2021.9595047
关键词
modular multilevel converter (MMC); voltage ripple; voltage fluctuation; dc-dc; switching-cycle; balancing; communication; timing; silicon carbide (SiC); medium voltage; high voltage
类别
资金
- Advanced Research Projects Agency-Energy (ARPA-e) from the Department of Energy (DOE) [DEAR0000892]
Traditional control of modular multilevel converters can lead to large capacitor voltage ripples, but the use of switching-cycle control can eliminate this dependency and enable operation in DC-DC mode. To address the challenges of precise arm-current shaping in each switching cycle, a distributed control architecture and custom-built controller system were designed to enhance flexibility and scalability.
Modular multilevel converters (MMC) with conventional control are subjected to large capacitor voltage ripples, especially at low-line-frequencies. It is proved that with appropriate arm current shaping in the timescale of switching period, referred as the switching-cycle control (SCC), such line-frequency dependence can be eliminated and MMCs are enabled to work even in dc-dc mode. Yet the SCC demands precise arm-current shaping in each switching cycle, posing great challenges on digital implementation. In this paper, SCC features are carefully investigated and based on control functions and timing constraints, SCC is separated into multiple control layers. A distributed control architecture and accordingly a custom-build controller system are designed, granting the system with enhanced flexibility and scalability. Detailed timing chart is presented to visualize the temporal cooperation among distributed controller units. Digital delays in the distributed system are identified and minimized to optimize the control performance. The proposed distributed digital implementation is verified in dc-dc operations with a custom-build SiC-based MMC prototype under 6 kV dc-link voltage.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据