A Hybrid Modular Multilevel Converter With Novel Three-Level Cells for DC Fault Blocking Capability
A Hybrid Modular Multilevel Converter With Novel Three-Level Cells for DC Fault Blocking Capability
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DOI：
10.1109/tpwrd.2015.2423258
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发表时间：
2015-04
影响因子：
4.4
通讯作者：
Rui Li;J. Fletcher;Lie Xu;D. Holliday;B. Williams
中科院分区：
文献类型：
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作者：
Rui Li;J. Fletcher;Lie Xu;D. Holliday;B. Williams
提出了一种新颖的混合模块化多电平变换器，其利用半桥和新颖的三电平单元的组合，其中三电平单元利用箝位电路，该箝位电路在直流侧故障下能够阻断故障电流，从而避免续流二极管中的过电流。这种直流故障阻断能力是通过仿真证明，并被证明是一样好的模块化多电平转换器，利用全桥单元，但具有额外的好处：较低的传导损耗，更少的二极管和半导体开关器件，和，更少的直通模式。所提出的变换器的半导体数量和导通损耗分别减少到基于全桥单元的模块化多电平变换器的66.5%和72%左右，从而降低了半导体成本并提高了效率。由于转换器的全直流故障阻断能力，在不将半导体暴露于显著故障电流和过电压的情况下实现直流故障穿越操作。
A novel hybrid, modular multilevel converter is presented that utilizes a combination of half-bridge and novel three-level cells where the three-level cells utilize a clamp circuit which, under dc side faults, is capable of blocking fault current thereby avoiding overcurrents in the freewheel diodes. This dc fault blocking capability is demonstrated through simulation and is shown to be as good as the modular multilevel converter which utilizes full-bridge cells but with the added benefits of: lower conduction losses; fewer diode and semiconductor switching devices, and; fewer shoot-through modes. The semiconductor count and conduction loss of the proposed converter are reduced to around 66.5% and 72% of that of modular multilevel converter based on the full-bridge cells respectively, yielding lower semiconductor cost and improved efficiency. Dc fault ride-through operation is realized without exposing the semiconductors to significant fault currents and overvoltages due to the full dc fault blocking capability of the converter.