New Submodule Improving Fault-Tolerant Capability of Modular Multilevel Converters
New Submodule Improving Fault-Tolerant Capability of Modular Multilevel Converters
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DOI：
10.1109/tec.2020.2971910
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发表时间：
2020-06
影响因子：
4.9
通讯作者：
A. Ghazanfari;Y. Mohamed
中科院分区：
文献类型：
--
作者：
A. Ghazanfari;Y. Mohamed
本文提出了一种新的子模块（SM）电路，有利于容错能力的模块化多电平变换器（MMC）在各种内部和外部故障。建议的SM电路确保MMC的连续操作后，多个SM故障和对称和非对称电网故障，而不需要额外的硬件实现。建议SM电路可以简单地集成到传统的半桥为基础的MMC通过使用开关信号适配器块。开关信号适配器单元适时地将开关模式分配给每个臂中的SM，以获得最有效的电流路径和固有的电容器电压平衡特征。一个完全模块化的结构，增强的内部故障管理，外部故障处理能力，易于扩展的SM电路的主要特点。详细讨论和分析了采用该SM的MMC的配置、建模和选通信号模式。时域仿真研究，使用详细的非线性模型验证了所提出的配置和它的工作原理在MMC-HVDC系统在各种故障条件下的有效性。此外，硬件在环测试结果证实了所提出的SM电路的硬件实现的可行性。
This article presents a new submodule (SM) circuit that facilitates the fault-tolerant capability for modular multilevel converters (MMCs) under various internal and external faults. The proposed SM circuit ensures continued operation of the MMC subsequent to multiple SM failures and symmetrical and asymmetrical grid faults without the need for additional hardware implementation. The proposed SM circuit can be simply integrated into conventional half bridge-based MMCs by using the switching signal adapter block. The switching signal adapter unit duly assigns a switching pattern to the SMs in each arm to obtain the most efficient current path and inherent capacitor voltage balancing features. A fully modular structure, enhanced internal fault management, external fault-handling capability, and ease of expandability are the key features of the proposed SM circuit. The configuration, modeling, and gating signal pattern of an MMC that adopts the proposed SM are discussed and analyzed in detail. Time-domain simulation studies using detailed nonlinear models validate the effectiveness of the proposed configuration and its principle of operation in an MMC-HVDC system under various fault conditions. In addition, hardware-in-the-loop test results confirm the feasibility of hardware implementation of the proposed SM circuit.