Precharging and DC Fault Ride-Through of Hybrid MMC-Based HVDC Systems
Precharging and DC Fault Ride-Through of Hybrid MMC-Based HVDC Systems
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DOI：
10.1109/tpwrd.2014.2360042
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发表时间：
2015-06
影响因子：
4.4
通讯作者：
R. Zeng;Lie Xu;L. Yao;D. Morrow
中科院分区：
文献类型：
--
作者：
R. Zeng;Lie Xu;L. Yao;D. Morrow
与基于半桥的模块化多电平变换器（MMC）相比，基于全桥的系统具有阻断直流故障的优点，但以增加功率半导体和功率损耗为代价。针对负电压状态下全桥MMC中交流/直流电压和电流之间的关系，详细分析了电容电压变化与最大调制指数之间的联系。针对混合MMC的预充电过程和暂态直流故障穿越能力，研究了一种混合MMC，它由半桥和全桥电路组成，充分发挥了联合收割机的各自优点。仿真和实验结果验证了所提出的全桥MMC和混合MMC控制策略的可行性和有效性。
Compared to half-bridge-based modular multilevel converters (MMCs), full-bridge-based systems have the advantage of blocking the dc fault, but at the expense of increased power semiconductors and power losses. In view of the relationships among ac/dc voltages and currents in full-bridge-based MMC with the negative voltage state, this paper provides a detailed analysis on the link between capacitor voltage variation and the maximum modulation index. A hybrid MMC, consisting of mixed half-bridge and full-bridge circuits to combine their respective advantages is investigated in terms of its precharging process and transient dc fault ride-through capability. Simulation and experiment results demonstrate the feasibility and validity of the proposed strategy for a full-bridge-based MMC and the hybrid MMC.