A Novel Fault-Tolerant Control Method for Modular Multilevel Converters
A Novel Fault-Tolerant Control Method for Modular Multilevel Converters
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DOI：
10.1109/ifeec47410.2019.9015155
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发表时间：
2019-11
期刊：
影响因子：
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通讯作者：
Lixia Yang;Lixin Jia;Longfei Luo;Yanbin Zhang;Linlin Zhao;Zhuxiang Zhang
中科院分区：
文献类型：
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作者：
Lixia Yang;Lixin Jia;Longfei Luo;Yanbin Zhang;Linlin Zhao;Zhuxiang Zhang
近年来，随着模块化多电平换流器（MMC）的迅速发展及其在高压直流输电系统、电动机拖动等领域的应用，其安全可靠运行越来越受到人们的关注。提出了一种MMC子模块故障下的半热备冗余方法。在该方法中，冗余SM与普通SM一样参与不受控制的预充电。在不受控制的预充电之后，在MMC正常操作下，冗余SM被控制在电压平衡状态。如果一个普通SM发生故障，故障SM将立即被旁路，同时冗余SM将被重新充电。当冗余SM充电至额定电压时，会迅速插入以更换故障SM，以维持MMC系统的稳定连续运行。该方法能快速减小环流振荡，保证MMC系统在SM故障时的正常运行。该方法实现简单，不需要改变MMC系统原有的调制策略和电容电压平衡控制。最后，在PSCAD/EMTDC中建立了一个21电平的双端MMC系统，验证了所提方法的有效性。
Recently, with the rapid development and the application of modular multilevel converter (MMC) in high voltage direct current (HVDC) transmission system, motor drive and other fields, more and more attention has been paid to it’s safe and reliable operation. This paper proposed a semi-hot reserved redundancy method under MMC sub-modules (SMs) failure. In this method, redundant SMs participate in uncontrolled precharge as ordinary SMs. After uncontrolled precharge, the redundant SMs are controlled in voltage balance state under MMC normal operation. If an ordinary SM failed, the faulty SM will be bypassed immediately and the redundant SM will be recharged at the same time. When the redundant SM is recharged to the rated voltage, it will be inserted quickly to replace the faulty SM to maintain the stable and continuous operation of the MMC system. The proposed method can quickly reduce the circulating current oscillation and guarantee the MMC system normal operation under SMs failure. The method is simple to achieve and there is no need to change the original modulation strategy and capacitor voltage balance control of the MMC system. Finally, a 21-level two-terminal MMC system is built in PSCAD/EMTDC to validate the effectiveness of the proposed methods.